Thesis PREET PRATIMA. DOCTOR OF PHILOSOPHY in HORTICULTURE (FRUIT SCIENCE)

Transcription

1 STUDIES ON WATER RELATIONS AND DEFICIT IRRIGATION IN KIWIFRUIT (Actinidia deliciosa Chev.). Thesis by PREET PRATIMA Submitted in partial fulfilment of the requirements for the degree of DOCTOR OF PHILOSOPHY in HORTICULTURE (FRUIT SCIENCE) 1985 COLLEGE OF HORTICULTURE Dr. Yashwant Singh Parmar University of Horticulture and Forestry, Nauni, Solan (H.P.), INDIA 2014

2 Dr N Sharma Professor Department of Fruit Science College of Horticulture Dr. Y. S. Parmar University of Horticulture and Forestry, Nauni-Solan (H.P.) CERTIFICATE-I This is to certify that the thesis entitled, Studies on water relations and deficit irrigation in kiwifruit ( Actinidia deliciosa Chev.), submitted in partial fulfillment of the requirements for the award of degree of Doctor of Philosophy in Horticulture (Fruit Science) to Dr. Yashwant Singh Parmar University of Horticulture and Forestry, Nauni, Solan (H.P.) is a bonafide record of research work carried out by Ms. Preet Pratima (H D) under my guidance and supervision. No part of this thesis has been submitted for any other degree or diploma. The assistance and help received during the course of investigation has been fully acknowledged. Place: Nauni- Solan Dated: (N. Sharma) Chairman Advisory Committee

3 CERTIFICATE-II This is to certify that the thesis entitled Studies on water relations and deficit irrigation in kiwifruit ( Actinidia deliciosa Chev.), submitted by Ms. Preet Pratima (H D) to Dr Y S Parmar University of Horticulture and Forestry, Nauni, Solan (HP), in partial fulfilment of the requirements for the award of degree of DOCTOR OF PHILOSOPHY in HORTICULTURE (Fruit Science) has been approved by the Advisory Committee after the thesis viva-voce examination in collaboration with the external examiner. Dr N Sharma Chairman, Advisory Committee Dr K K Pramanick External Examiner Members, Advisory Committee Dr D P Sharma Professor Department of Fruit Science Dr (Mrs.) Anju Thakur Professor Department of Basic Sciences Dr Rajesh Kaushal Associate Professor Department of Basic Sciences Dr Vishal S Rana Scientist Department of Fruit Science Dr A K Sharma Dean's Nominee Professor and Head Department of Fruit Science Dean College of Horticulture Dr Y S Parmar UH&F, Nauni, Solan (HP), India

4 CERTIFICATE-III This is to certify that all the mistakes and errors pointed out by the external examiner have been incorporated in the thesis entitled, Studies on water relations and deficit irrigation in kiwifruit (Actinidia deliciosa Chev.), submitted to Dr. Yashwant Singh Parmar University of Horticulture and Forestry, Nauni, Solan (H.P.) by Ms. Preet Pratima (H D) in partial fulfillment of the requirements for the award of degree of Doctor of Philosophy in Horticulture (Fruit Science). Major Advisor Dr. N. Sharma Professor, Deptt. of Fruit Science Professor and Head Department of Fruit Science Dr Y S Parmar UHF, Nauni, Solan (H.P.)

5 ACKNOWLEDGEMENT I would like to express my gratitude and profound personal regards to my esteemed teacher and Chairman of Advisory Committee, Dr. N. Sharma, Professor who has patiently supervised this research work and has enthusiastically provided expertise, positive suggestions, inspiration, encouragement and guidance throughout. I shall ever remain indebted to him for his benevolence and affection so generously vested upon me and also for his constructive criticism in transforming the manuscript into the present form. It is my privilege to express my profound thanks to Dr Anju Thakur, Dr D.P. Sharma, Dr Rajesh Kaushal and Dr Vishal S. Rana members of my advisory committee, for their inspiring guidance and valuable suggestions, expertise and feedback throughout the course of this investigation. With the immense pleasure, I thank Dr P. S. Chauhan, Professor & Head, Department of Fruit Science for providing me all the facilities and help to carry out the present research. I am also thankful to all members of faculty, laboratory, field and ministerial staff of the Department of Fruit Science, Nauni, Solan for the help rendered by them. I also thankful to Dr. Y.P. Sharma for his valuable source of technical advice for the use of HPLC and I also value to the help I received from Mrs. Sarla Tomar and Shweta Sharma working with HPLC. Thanks are also extended to Dr S. S. Sharma for his whole hearted help in anatomical studies. I have no words to express my feelings towards my respected parents, affectionate father, Shri R.M. Mandhotra, mother, Smt Champa Mandhotra who kept me away from all domestic worries at the cost of their comforts. The support and interest of my younger brother, Nishant Mandhotra is also appreciated. Most of all, I consider myself incredibly fortunate to have had the support of one unselfish, patient and outstanding person in particular, my beloved husband Samjeet Singh Thakur. Words are incapable of expressing my sincere feelings towards my friends Chaitanya, Kapil, Dilip, Niranjan, Vikas, Rimpika and all the seniors of my department for their valuable help during the entire course of study. Errors and omissions are mine. Place: Nauni, Solan Date: 18 th Feb, 2014 (Preet Pratima)

6 CONTENTS Chapter Title Pages 1. INTRODUCTION REVIEW OF LITERATURE MATERIALS AND METHODS EXPERIMENTAL RESULTS DISCUSSION SUMMARY AND CONCLUSION REFERENCES ABSTRACT 287 APPENDICES i-xxix

7 LIST OF TABLES Tables Title Pages Soil moisture level at different atmospheric tensions in kiwifruit vineyard The details of staining procedure for anatomical studies of kiwifruit shoot Effect of different irrigation levels on shoot growth (cm) of kiwifruit cultivars Effect of different irrigation levels on length of internodes (cm) of kiwifruit cultivars Effect of different irrigation levels on leaf area (cm 2 ) of kiwifruit cultivars Effect of different irrigation levels on leaf thickness (mm) of kiwifruit cultivars Effect of different irrigation levels on leaf yellowing (%) of kiwifruit cultivars Effect of different irrigation levels on bloom intensity (%) of kiwifruit cultivars Effect of different irrigation levels on fruit set (%) of kiwifruit cultivars Effect of different irrigation levels on fruit retention (%) of kiwifruit cultivars Effect of different irrigation levels on fruit yield (Kg/vine) of kiwifruit cultivars Effect of different irrigation levels on graded yield (% of total fruit yield) of kiwifruit cultivars during Effect of different irrigation levels on graded yield (% of total fruit yield) of kiwifruit cultivars during Effect of different irrigation levels on graded yield (%) of kiwifruit cultivars during (pooled) 104

8 Tables Title Pages Dates on which irrigation was given to kiwifruit vines under different levels of irrigations (2011) Dates on which irrigation was given to kiwifruit vines under different levels of irrigations (2012) Effect of different irrigation levels on canopy temperature ( o C) of kiwifruit cultivars Effect of different irrigation levels on stomatal pore length (µm) of kiwifruit cultivars Effect of different irrigation levels on stomatal pore width (µm) of kiwifruit cultivars Effect of different irrigation levels on stomatal density (per 0.04 mm 2 ) of kiwifruit cultivars Effect of different irrigation levels on leaf water potential (-bars) of kiwifruit cultivars Effect of different irrigation levels on stomatal resistance (S cm -1 ) of kiwifruit cultivars Effect of different irrigation levels on transpiration rate (m mol m -2 s -1 ) of kiwifruit cultivars Effect of different irrigation levels on photosynthetic rate (µmol m -2 s -1 ) of kiwifruit cultivars Effect of different irrigation levels on chlorophyll content (mg/g) of kiwifruit cultivars Effect of different irrigation levels on CSI (%) of kiwifruit cultivars Effect of different irrigation levels on proline content (µg/g fresh weight basis) of kiwifruit cultivars Effect of different irrigation levels on free amino acids (mg/g fresh weight basis) contents of kiwifruit cultivars Effect of different irrigation levels on RWC (%) of kiwifruit cultivars Effect of different irrigation levels on the number of primary xylem of kiwifruit cultivars

9 Tables Title Pages Effect of different irrigation levels on length of secondary xylem (µm) of kiwifruit cultivars Effect of different irrigation levels on cytokinin (ZR ρg/g fresh weight basis) content of kiwifruit cultivars Effect of different irrigation levels on ABA (ηg/g fresh weight basis) content of kiwifruit cultivars Effect of different irrigation levels on nitrogen content (%) of kiwifruit cultivars Effect of different irrigation levels on phosphorus content (%) of kiwifruit cultivars Effect of different irrigation levels on potassium content (%) of kiwifruit cultivars Effect of different irrigation levels on calcium content (%) of kiwifruit cultivars Effect of different irrigation levels on magnesium content (%) of kiwifruit cultivars Effect of different irrigation levels on fruit length (mm) of kiwifruit cultivars Effect of different irrigation levels on fruit diameter (mm) of kiwifruit cultivars Effect of different irrigation levels on fruit weight (g) of kiwifruit cultivars Effect of different irrigation levels on fruit firmness (Kg/cm2) of kiwifruit cultivars Effect of different irrigation levels on TSS (0B) of kiwifruit cultivars Effect of different irrigation levels on titratable acidity (%) of kiwifruit cultivars Effect of different irrigation levels on total sugars (%) of kiwifruit cultivars Effect of different irrigation levels on reducing sugars (%) of kiwifruit cultivars

10 Tables Title Pages Effect of different irrigation levels on non reducing sugars (%) of kiwifruit cultivars Effect of different irrigation levels on ascorbic acid (mg/100g) of kiwifruit cultivars Effect of irrigation levels and mulching on shoot growth (cm) of kiwifruit cv. Allison Effect of irrigation levels and mulching on length of internodes (cm) kiwifruit cv. Allison Effect of irrigation levels and mulching on leaf area (cm2) of kiwifruit cv. Allison Effect of irrigation levels and mulching on leaf thickness (mm) of kiwifruit cv. Allison Effect of irrigation and mulching treatments on leaf yellowing (%) of kiwifruit cv. Allison Effect of irrigation levels and mulching on bloom intensity (%) of kiwifruit cv. Allison Effect of irrigation levels and mulching on fruit set (%) of kiwifruit cv. Allison Effect of irrigation levels and mulching on fruit retention (%) of kiwifruit cv. Allison Effect of irrigation levels and mulching on total fruit yield (Kg/vine) of kiwifruit cv. Allison Effect of irrigation levels and mulching on yield of A grade fruit (% of total yield) of kiwifruit cv. Allison Effect of irrigation levels and mulching on yield of B grade fruit (% of total yield) of kiwifruit cv. Allison Effect of irrigation levels and mulching on yield of C grade fruit (% of total yield) of kiwifruit cv. Allison Effect of irrigation levels and mulching on yield of D grade fruit (% of total yield) of kiwifruit cv. Allison Dates on which irrigation was given to kiwifruit vines under various water deficit treatments (2011)

11 Tables Title Pages Dates on which irrigation was given to kiwifruit vines under various water deficit treatments (2012) Effect of irrigation levels and mulching on canopy temperature (oc) of kiwifruit cv. Allison Effect of irrigation levels and mulching on stomatal pore length (µm) of kiwifruit cv. Allison Effect of irrigation levels and mulching on stomatal pore width (µm) of kiwifruit cv. Allison Effect of irrigation and mulching treatments on stomatal density (No/ 0.04 mm2) of kiwifruit cv. Allison Effect of irrigation and mulching on leaf water potential (-bars) of kiwifruit cv. Allison Effect of irrigation and mulching treatments on stomatal resistance (S cm-1) of kiwifruit cv. Allison Effect of irrigation and mulching treatments on transpiration rate (m mol m-2s-1) of kiwifruit cv. Allison Effect of irrigation and mulching treatments on photosynthetic rate (µ mol m-2s-1) of kiwifruit cv. Allison Effect of irrigation and mulching treatments on leaf chlorophyll content (mg/g) of kiwifruit cv. Allison Effect of deficit irrigation and mulching on CSI (%) of kiwifruit cv. Allison Effect of irrigation and mulching treatments on proline content (µg/g fresh weight basis) of kiwifruit cv. Allison Effect of irrigation and mulching treatments on free amino acids (mg/g fresh weight basis) of kiwifruit cv. Allison Effect of irrigation and mulching treatments on RWC (%) of kiwifruit cv. Allison Effect of irrigation and mulching treatments on number of primary xylem of kiwifruit cv. Allison Effect of irrigation and mulching treatments on length of secondary xylem (µm) of kiwifruit cv. Allison

12 Tables Title Pages Effect of irrigation levels and mulching treatments on cytokinin (ZR ρg/g fresh weight basis) content of kiwifruit cv. Allison Effect of irrigation levels and mulching treatments on ABA (ηg/g fresh weight basis) content of kiwifruit cv. Allison Effect of irrigation and mulching treatments on leaf nitrogen content (%) of kiwifruit cv. Allison Effect of irrigation and mulching treatments on leaf phosphorus content (%) of kiwifruit cv. Allison Effect of irrigation and mulching treatments on potassium content (%) of kiwifruit cv. Allison Effect of irrigation and mulching treatments on leaf calcium content (%) of kiwifruit cv. Allison Effect of irrigation and mulching treatments on magnesium content (%) of kiwifruit cv. Allison Effect of irrigation and mulching treatments on fruit length (mm) of kiwifruit cv. Allison Effect of irrigation and mulching treatments on fruit diameter (mm) of kiwifruit cv. Allison Effect of irrigation and mulching treatments on fruit weight (g) of kiwifruit cv. Allison Effect of irrigation and mulching treatments on fruit firmness (Kg/cm2) of kiwifruit cv. Allison Effect of irrigation and mulching treatments on fruit TSS (0B) in kiwifruit cv. Allison Effect of irrigation and mulching treatments on fruit titratable acidity (%) of kiwifruit cv. Allison Effect of irrigation and mulching treatments on total sugars contents (%) of kiwifruit cv. Allison Effect of irrigation and mulching treatments on reducing sugars (%) contents of kiwifruit cv. Allison Effect of irrigation and mulching treatments on nonreducing sugar content (%) of kiwifruit cv. Allison Effect of irrigation and mulching treatments on ascorbic acid content (mg/100g) of kiwifruit cv. Allison

13 LIST OF FIGURES Figure Title Pages/Between pages Per cent reduction in shoot growth of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent reduction in length of internodes of different kiwifruit cultivars at irrigation at 60 per cent FC over 80 per cent FC Per cent reduction in leaf area of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent increase in leaf thickness (mm) of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent increase in leaf yellowing of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent reduction in bloom intensity (%) of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent reduction in fruit set (%) of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent reduction in fruit retention of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent reduction in total fruit yield of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent reduction in A grade fruit yield of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent reduction in B grade fruit yield of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent increase in C grade fruit yield of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent increase in D grade fruit yield of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC

14 Figure Title Pages/Between pages Average soil moisture content (%) of five cultiv ars of kiwifruit under two irrigation levels at 30 cm soil depth (a) and at 60 cm soil depth (b) during the year a b c d Average soil moisture content (%) of five cultivars of kiwifruit under two irrigation levels at 30 cm soil depth (a) and at 60 cm soil depth (b) during the year 2012 Periodic soil moisture content at 30 cm soil depth during 2011 as affected by irrigation treatments (80 %FC) in kiwifruit cultivars Periodic soil moisture content at 30 cm soil depth during 2011 as affected by irrigation treatments (60% FC) in kiwifruit cultivars Periodic soil moisture content at 60 cm soil depth during 2011 as affected by irrigation treatments (80% FC) in kiwifruit cultivars Periodic soil moisture content at 60 cm soil depth during 2011 as affected by irrigation treatments (60% FC) in kiwifruit cultivars a b c d a b Periodic soil moisture content at 30 cm soil depth during 2012 as affected by irrigation treatments (80 %FC) in kiwifruit cultivar Periodic soil moisture content at 30 cm soil depth during 2012 as affected by irrigation treatments (60 %FC) in kiwifruit cultivars Periodic soil moisture content at 60 cm soil depth during 2012 as affected by irrigation treatments (80 %FC) in kiwifruit cultivar Periodic soil moisture content at 60 cm soil depth during 2012 as affected by irrigation treatments (60 %FC) in kiwifruit cultivars Average soil moisture content during 2011at 30 cm soil depth as affected by irrigation treatments in kiwifruit cultivars Average soil moisture content during 2011at 60 cm soil depth as affected by irrigation treatments in kiwifruit cultivars

15 Figure Title Pages/Between pages a Average soil moisture content during 2012 at 30 cm soil depth as affected by irrigation treatments in kiwifruit cultivars b Average soil moisture content during 2012 at 60 cm soil depth as affected by irrigation treatments in kiwifruit cultivars Depletion of soil moisture content (%) due to deficit irrigation in comparison to standard irrigation regime under different Kiwifruit cultivars Per cent increase in canopy temperature of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent reduction in stomatal pore length of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent reduction in stomatal pore width of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent increase in stomatal density of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent reduction in leaf water potential of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent increase in stomatal resistance of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent reduction in transpiration rate of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent reduction in photosynthetic rate of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent Per cent reduction in chlorophyll content of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC

16 Figure Title Pages/Between pages Per cent increase in chlorophyll stability index of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent increase in proline content of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent increase in free amino acid content of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent reduction in relative water content of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent reduction in number of primary xylem of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent reduction in length of secondary xylem of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent reduction in cytokinin content of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent increase in ABA content of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent reduction in nitrogen content of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent reduction in phosphorus content of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent reduction in potassium content of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent reduction in calcium content of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent reduction in magnesium content of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC

17 Figure Title Pages/Between pages Per cent reduction in fruit length of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent reduction in fruit diameter of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent reduction in fruit weight of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent increase in firmness of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent reduction in TSS content of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent reduction in titratable acidity of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent increase in total sugars of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC a b c Per cent increase in reducing sugars of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent increase in non reducing sugars of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Per cent reduction in ascorbic acid content of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Periodic soil moisture contents at 30 cm depth (2011) under the vines of kiwifruit cultivar Allison as affected by irrigation treatments Periodic soil moisture contents at 60 cm depth (2011) under the vines of kiwifruit cultivar Allison as affected by irrigation treatments Periodic soil moisture contents at 30 cm depth (2012) under the vines of kiwifruit cultivar Allison as affected by irrigation treatments

18 Figure Title Pages/Between pages d Periodic soil moisture contents at 60 cm depth (2012) under the vines of kiwifruit cultivar Allison as affected by irrigation treatments Average soil moisture content (%) of kiwifruit cv. Allison under different irrigation levels and in situ moisture conservation treatments at 30 cm and 60 cm soil depths during the year 2011 Average soil moisture content (%) of kiwifruit cv. Allison under different irrigation levels and in situ moisture conservation treatments at 30 cm and 60 cm soil depths during the year 2012 Effect of in situ moisture conservation and deficit irrigation treatments on soil moisture content (%) 30 and 60 cm depth in kiwifruit cv. Allison during 2011 Effect of in situ moisture conservation and deficit irrigation treatments on soil moisture content (%) 30 and 60 cm depth in kiwifruit cv. Allison during 2012 Average soil moisture content (%) un der different irrigation levels and in situ moisture conservation treatments in kiwifruit cv. Allison at 30 cm and 60 cm soil depths during the year 2011 and

19 LIST OF PLATES Plate Title Between Pages 1 Field observations (A-D) and use of mulches (E-F) a Stomatal pore size and density of kiwifruit cv. Allison b Stomatal pore size and density of kiwifruit cv. Hayward c Stomatal pore size and density of kiwifruit cv. Abbott d Stomatal pore size and density of kiwifruit cv. Monty e Stomatal pore size and density of kiwifruit cv. Bruno a 3 b 3 c 3d 3 e 4 5 Xylem vessel development in shoot section of kiwifruit cv. Allison Xylem vessel development in shoot section of kiwifruit cv. Hayward Xylem vessel development in shoot section of kiwifruit cv. Abbott Xylem vessel development in shoot section of kiwifruit cv. Monty Xylem vessel development in shoot section of kiwifruit cv. Bruno Effect of irrigation levels on fruit size of different kiwifruit cultivars Stomatal structure of kiwifruit cultivar Allison under different treatments Xylem vessel development in kiwifruit cv. Allison Effect of different irrigation levels on size of kiwifruit cv. Allison

20 ABBREVIATIONS ABA BPM CSI DI FC GM MPa PRD RBD RDI RH RWC TSS ZR η ρ Ψ Abscisic acid Black Polyethylene mulch Chlorophyll Stability Index Deficit Irrigation Field Capacity Grass mulch Mega Pascal Partial Rootzone Drying Randomized Block Design Regulated Deficit Irrigation Relative humidity Relative Water Content Total Soluble Solids Zeatin Riboside nano pico Water potential µ micro

21 Chapter-1 INTRODUCTION The kiwifruit or Chinese gooseberry ( Actinidia deliciosa Chev.) is a deciduous fruit vine, native to Yangtze valley of south and central China (Ferguson, 1984). It is a dioecious vine, bearing pistillate and staminate flowers separately and requires chilling hours below 7 o C and mild summer with temperature not exceeding 35 o C. In India, therefore it can be grown successfully in areas situated at elevation of m above mean sea level where, the winters are cold and summers are warm and humid, and receive well distributed annual rainfall of about 150 cm. A deep friable well-drained sandy loam to clay soil coupled with assured irrigation is one of the ideal conditions for growing kiwifruit. The fruit has an excellent table and keeping quality and acclaimed for its nutritive and medicinal values. Kiwifruit is a rich source of vitamin C, vitamin K, and vitamin E and provides dietary fibre and minerals like P, K and Ca. Approximately, 84 per cent of the world kiwifruit production is contributed by China, Italy, New Zealand and Chile. In India, the area under this fruit is negligible, however, it can be successfully adapted in the mid hills of Himachal Pradesh, Uttarakhand, J & K, Sikkim, Meghalaya, Arunachal Pradesh, Assam, Nagaland, Manipur, Mizoram, Tripura, Nilgiri Hills and Kerala. In Himachal Pradesh, it occupied an area of 128 ha with annual production of 118 metric tons during the year 2009 (Anonymous, 2009). Arunachal Pradesh is now the highest producer of kiwifruit with MT annual productions, due to sufficient water availability. In fact no other fruit has gained so much popularity in such a short period in the history of commercial production. At present seven cultivars of kiwifruit that include female cultivars namely, Allison, Monty, Hayward, Abbott and Bruno and male cultivars Tomuri and Matua have been introduced in India. However, economic returns from kiwifruit depend strongly on fruit size, which are in turn directly affected by availability of water (Judd and McAneney, 1987). The water requirement of

22 kiwifruit plants is high due to their vigorous vegetative growth, larger leaf size, vine habit and high humidity in their natural habitat. Kiwifruit vines are prone to water stress mainly because of their very large leaves and very high rate of water conductivity and transpiration rate. Kiwifruit has poor stomatal control (Buwalda and Smith, 1990), however, Chartzoulakis et al. (1993) reported that A. deliciosa seedlings showed poor control of transpiration even though there was a reduction in stomatal conductance (g s ) and suggested that this species has poor epidermal control of water loss through leaky stomata or an insufficient cutinisation of the epidermis. Symptoms of drought stress are decreased shoot growth, drooping leaves, browning of the leaves around the edges, and complete defoliation with re-growth of new shoots when the stress is continuous. Lack of water can also reduce the amount of blooms, reduce fruit size and cause early fruit drop. It can also cause fruit to ripen too early, which causes uneven ripening and produces fruit with poor flavour. In situations of severe water stress, vine leaves will turn yellow. Kiwi vines probably die more often from some type of water stress than any other problems. It is known that a significant reduction in harvest weight will occur if the irrigation supply is limited over the summer. This effect is particularly severe if vines are drought stressed early in the growing season when fruit are in their most rapid phase of expansion. If the water is limiting during the early fruit growth, any reduction in fruit size is irreversible. In Himachal Pradesh, however, kiwifruit cultivation has extended to those areas where, demand for water exceeds that of local resources. The problem of water limitation may prove to be a more critical constraint to temperate fruit productivity in future due to global environmental change. However, some plants may adapt to changing environment more easily than others. Plant responses to water scarcity are complex, involving adaptive changes and/or deleterious effects. Plant strategies to cope with drought normally involve a mixture of stress avoidance and tolerance strategies that vary with genotype. Systematic studies on different anatomical and physiological parameters such as stomatal size and density, xylem vessel development, leaf water potential, stomatal conductance, transpiration and chlorophyll stability index might provide useful information about water relation and water stress resistance in kiwifruit. 2

23 Stressed plants also accumulate abscisic acid (Sharma and Sharma, 2008a) and compatible solutes such as proline and free amino acid (Morgan, 1984), which play an important role in adaptive responses to water stress. In kiwifruit, the potential of cultivar(s) to adapt under water scarcity conditions is not much known and therefore, evaluation of cultivar(s) best suited for water stress conditions is required. Regulated deficit irrigation (RDI) is an irrigation management technique that utilizes water stress as a tool to increase fruit quality. In RDI the water input is removed or reduced for specific periods during the crop cycle, improving control of vegetative vigour, to optimize fruit size, fruitfulness and fruit quality (Chalmers et al., 1986; Alegre et al., 1999; Dry et al., 2001). The improvement in fruit taste and quality along with postharvest shelf life has also been reported under RDI (Fereres and Goldham er, 1990; Crisosto et al., 1994). The primary objective of RDI is to increase fruit quality through the application of controlled water stress. Water stress is controlled under RDI by the application of short irrigations at specific soil moisture levels (Goodwin, 2009). Regulated deficit irrigation has been used successfully with several crops, reducing water use in crops, such as olive trees (Wahbi et al., 2005), peaches (Boland et al., 1993), pears (Marsal et al., 2002) and grapevines (Battilani, 2000). The efficiency of deficit irrigation (whatever the sub -type) in modulating water use efficiency, growth and grape berry composition depends on the varietal characteristics such as vigour and drought avoiding traits, the type of soil and the prevailing weather (Chaves et al., 2010). The use of different mulching materials is known to be beneficial for in situ moisture conservation during the drought period (Guleria, 1986). Mulches also regulate soil temperature, prevent soil erosion, surface run-off of water and control the weeds. Organic mulch helps prevent winter injury to crowns, promotes growth of the extensive fibrous kiwifruit root system, and helps control unwanted suckers. Hay and straw mulch materials are easily available and comparatively cheaper than other mulch materials. Organic mulch decomposes easily and adds manures to the field. However, the black plastic mulch of gauges with desired dimension has been in use commercially in different 3

24 countries. Using black plastic mulch is advantageous as higher yields of better quality fruits are obtained (Sharma, 2002). The plastic mulch can be recycled again but not hay or straw. The aim of in situ moisture conservation and deficit irrigation is to maintain water stress within a desirable range so that the physiological reactions of the vine can be harnessed to the benefit of the kiwifruit grower. Keeping in view the above points into consideration, the present investigation on water relations and deficit irrigations in kiwifruit was carried out with the following objectives: 1) Screening of water deficit tolerant cultivar (s) of kiwifruit for mid-hill conditions of HP. 2) To study the effect of in situ moisture conservation and deficit irrigation on growth, water relations and yield of kiwifruit. 4

25 Chapter-2 REVIEW OF LITERATURE Kiwifruit is quite sensitive to water stress throughout the growing season. Water deficit has been considered as the most important factor limiting fruit growth, yield and fruit quality in kiwifruit. It is known that a significant reduction in harvest weight will occur if the irrigation supply is limited over the summer. In Himachal Pradesh, however, kiwifruit cultivation has extended to those areas where demand for water exceeds that of local resources. It has therefore become necessary to use the available water judiciously and screen out most suitable cultivar(s) for such growing areas. Water stress may be controlled under regulated deficit irrigation (RDI) by the application of short irrigations at specific soil moisture levels (Goodwin, 2009). Moreover, RDI can be used for improving water use efficiency. The term regulated deficit irrigation was coined by a team of researchers led by David Chalmers based at Tatura, Victoria to describe the application of water deficit strategies based on orchard evapotranspiration relative to water loss from an evaporimeter. Besides, the use of different mulching materials has also been found beneficial for in situ moisture conservation during the drought period (Guleria, 1986). Mulch es also regulate soil temperature, prevent soil erosion, surface run-off of water and control the weeds. Further, organic mulch decomposes easily and adds manures to the field. However, the black plastic mulch of gauges with desired dimension has been in use commercially in different countries. Using black plastic mulch increased yields of better quality fruits (Sharma, 2002). 2.1 FRUIT CROP RESPONSE TO WATER STRESS In kiwifruit, although not much work has been done in relation to water stress resistance however, there are reports on this aspect in other fruit crops. The information related to the effect of water deficit on different parameters pertaining to the present studies has been reviewed as under:

26 2.1.1 VEGETATIVE GROWTH In kiwifruit, economic return is directly related to the vine size, which is strongly affected by availability of water (Judd and Mc Aneney, 1987). Apart from high soil moisture requirement, other optimal environmental conditions for growth of Actinidia deliciosa are low atmospheric vapour pressure deficit, high rainfall, long growing season, and the absence of strong winds (Ferguson, 1984). Fruit trees under continuous readily available soil moisture conditions during the growing period make more total growth than the trees under limited supply of moisture (Goode and Ingram, 1971). Soil moisture affects almost every aspect of plant growth and development by modifying morphological and biochemical characteristics (Hsiao, 1973). However, the vegetative growth is the most sensitive plant parameter to water stress Shoot growth In most woody crops, plant growth performance is limited by availability of soil water and photosynthetic carbon products (Flore and Lakso, 1989). Reynolds and Naylor (1994) observed that in grape cultivars Pinot noir and Riesling, the lateral shoot length decreased linearly with increased water stress duration; lag phase or veraison vines had the longest laterals and post bloom vines had the shortest. However, as water stress progressed, many main leaves abscised, followed by an apparent resumption in lateral shoot growth; hence, this linear trend was reversed later in the sampling period, in this study. However, shoot growth of container-grown wine grapes was reduced under partial root zone drying (Loveys et al., 2000). Sharma and Joolka (2001) observed that soil moisture levels influenced the shoot growth significantly in wild peach and bitter almond. In Clemenules mandarin, DI reduced canopy volume relative growth rate of plants grafted on Carrizo citrange rootstock more than that of Cleopatra mandarin rootstock, with reductions of 33 and 18% respectively (Romero et al., 2006). Sharma and Sharma (2009) compare d the performance pear cultivar Flemish Beauty on different rootstocks under -0.5 and -5.0 bar soil moisture regimes and observed significant reduction in plant height under water stress condition. However, 6

27 plants on rootstocks Kainth and BA 29 showed more resistance to water stress in comparison to Quince A and Quince C. In an experiment on characterization of eleven olive cultivars for drought tolerance, internodes length of shoot was affected significantly by water stress treatment, wherein, the maximum length of internodes as observed in cv. Gordal Sevilana (3.07cm) under well irrigated condition got reduced to 2.59 cm in response to water stress and the minimum value of intermodal length recorded in cv. Moraiolo (2.12 cm) was reduced to 1.74 cm after water stress treatment (Kumar, 2010). In another experiment under in vitro conditions for drought tolerance of two cultivars of pomegranate viz. Manfalouty and Nab El- Gamal, the internode length of these cultivars was decreased by 41.3 and 53.3 %, respectively and thus the Manfalouty cultivar was found slightly more tolerant to drought than Nab El- Gamal cultivar (El- Agamy et al., 2010). Yadollahi et al. (2010) reported that drought stress reduced shoot growth in almond cultivars Talkh, Shahrood 18 and Shahrood 12; however, in Butte, Shahrood 21 and Sefid cultivars shoot growth between control and stress plants was statistically at par Leaf area In avocado, moderate water stress significantly reduced the total plant leaf area by 57 and 69% for the cultivars Fuerte and Hass, respectively (Chartzoulakis et al., 2002). Gomez et al. (2003) reported that in grape cultivars Garnacha Tinta, Tempranillo, Chardonnay and Airen, water stress significantly reduced on an average the total leaf area of the vine by 57%, leaf area of lateral shoots by 19%, shoot by 12%, and individual leaf size by 13% and dry matter production by 55%. Chaves et al. (2007) observed that the total leaf area per vine at veraison presented higher values in cultivars Moscatel and Castelao under full irrigated than in non-irrigated and PRD vines. However, the deficit irrigated plants had intermediate values of total leaf area. In a study on two almond cultivars, drought stress decreased the leaf area of cv. Tuono significantly as compared to the cv. Princesse, and therefore cv. Tuono had more potential to tolerant drought stress than cv. Princesse (Gikloo and Elhami, 2012). 7

28 Leaf thickness Leaf morpho-anatomy and related biochemistry (epicuticular wax composition, lipid composition, mesophyll thickness etc.) play a role in explaining plant adaptation to water stress (Syvertsen et al., 1995; Boyer et al. 1997; Cameron et al., 2006). The reduction in the thickness of the mesophyll in the stressed plants due to reduction in cell size may be considered as drought adaptation mechanism (Cutler et al., 1977; Steudle et al., 1977). In avocado, cross-section of Fuerte and Hass leaves showed that in both the cultivars the palisade and total thickness of water-stressed leaves were lower than in controls. In both the cultivars, water stress resulted in a significant decrease of the thickness of almost all histological compartments of the mesophyll, as well as of the entire lamina thickness. In stressed plants of Fuerte the chlorenchyma cells were denser than those in a well irrigated one. As a consequence, the amount of intercellular spaces of water stressed leaves was lower than in control leaves ( Chartzoulakis et al., 2002). Kumar (2010) in a study on characterization of olive cultivars for drought tolerance observed that the leaf thickness was higher in cultivars Manzanilla and Moraiolo (0.62 mm) and lower in the cultivars Canino, Leccino, Cornicobra and Coratina, in response to water stress Leaf yellowing Detailed studies on drought tolerance of fifteen different Turkish grape cultivars, Kozak Beyazi, Siyah Razaki, Cavas, Amasya, Muskule, Hafizali, Sultani Cekirdeksiz, Tarsus Beyazi, Yapincak, Balbal, Erenkoy Beyazi, Pembe Gemre, Okuzgozu, Iskenderiye Misketi and Buca Razakisi revealed that the injury due to water deficit appeared first as yellowing and wilting of the leaves and was followed by death of the shoots (Eris and Soylu, 1990). However, yellowing of the leaves was much less distinct in Cavus and Tarsus Beyazi cultivars than in the others. Drooping leaves were the first sign in cv. Cavus, at the beginning of injury. Under water stress conditions, trees of olive cultivars 8

29 Leccino and Cipperesino usually exhibited leaf yellowing symptoms, which were however; more pronounced in the later (Singh and Sharma, 2010). In an experiment on drought stress on six modern Hevea clones (RRII 105, RRII 208, RRII 414, RRII 429, RRII 430 and RRIM 600) grown in polybag plants in polyhouse and field conditions, the clone RRII 429 showed relatively higher leaf scorching than the other clones upon drought imposition. Clones RRII 429 and RRII 208 showed higher percentage of drying and leaf fall and RRII 430 had least under polyhouse as well as under filed conditions (Ravichandran et al., 2011). Results under the field conditions showed that the clone RRII 430 was more tolerant to drought stress than other clones FLOWERING AND FRUITING Bloom intensity Irrigation when applied during the summer had a beneficial effect on fruit number; however, no difference in flowering pattern was detected in response to different irrigation treatments in kiwifruit cv. Hayward (Magliulo et al., 1991). Miller et al. (1998) recorded similar number of flowers (approx. 400 per vine) on all vines of Hayward cultivar of kiwifruit when subjected to different water stress treatments. Furthermore, there were no visible signs of carry-over effects of stress treatments imposed the previous season on different parameters of leaves, flowers or fruits. Deficit irrigation also affected flower quality in loquat cv. Algerie (Hueso and Cuevas, 2002). In this respect, control trees produced heavier flowers than deficit irrigated trees. Goldhamer and Viveros (2000) found that the degree of water deficit before harvest, obtained by progressively increasing the elapsed times of withholding irrigation, was positively related to flower density and fruit set, whereas stress intensity after harvest was correlated to a decrease in both parameters in almond. Lamp et al. (2001) also reported that in almond, stresses occurring during flower development reduce next season s crop yield because of a reduced flower quality. In olive, the examination of sex ratio of flowers revealed that cultivars Frontoio, Manzanillo and Pendolino had more than 80 per cent perfect flowers, 9

30 while Kalamata and Picual had less than 30 per cent when subjected to water stress ( Shubiao et al., 2002). Pollen viability was highest in cultivar Frontoio, intermediate in Kalamata and Picual and lowest in Manzanillo and Pendolino cultivars. Drought stress in olive trees reduced net assimilation of the leaf and the return bloom which could also limit yield in future years (Alegre, 2002). Most damage on water stress olive trees occurred to flowering, however and when drought stress continued until September, fruits were small in size and late in ripeness (Vrhovnik, 2004) Fruit set and fruit retention In macadamia cultivars Kau, Pahala and Own Choice, study on four irrigation treatments viz. saturated irrigation, normal irrigation (60% of soil water holding capacity), water deficiency (20% of soil water holding capacity) and unirrigated control revealed that fruit setting of cv. Kau under normal irrigation was higher (by 0.47 and 2.96 %) than for the third and fourth treatments. However, cultivar Pahala had 1.11 and 2.59 per cent and cultivar Own Choice 0.28 and 0.83 per cent more setting under normal irrigation over these treatments, respectively (Fu et al., 2002). In irrigation study, three cultivars of apple, Red Chief, Well Spur and Starkrimson grafted on EMLA-7 rootstocks subjected to different levels of irrigation (100, 80, 60 and 40% ET), Red Chief cultivar was found to be statistically superior to other cultivars in terms of fruit set and least fruit drop when irrigated at 80 per cent evapotranspiration (Chauhan et al., 2005). Soil moisture had a negative correlation with fruit drop in olive cultivars Leccino and Cippressino (Singh and Sharma, 2010) Fruit yield In kiwifruit cv. Hayward, the yield per surface unit depends on the number of buds, bud-break proportion, number of fruits per fruitful shoot, and means fruit mass (Buwalda and Smith, 1988). Chandler and Ferree (1990) observed that among two strawberry cultivars Surecrop and Raritan, the cultivar Surecrop showed higher gas exchange rates and minimal losses in yield when subjected to water deficiency. However, cultivar Raritan gave higher fruit yield than Surecrop under favourable conditions 10

31 than Surecrop. Thus Surecrop was found to be more resistant to drought than the cultivar Raritan. Reynolds and Naylor (1994) reported that the fruit yield of glasshouse-grown grapes cultivars Pinot Noir and Riesling was affected by water stress duration and soil water-holding capacity. Although both cultivars displayed similar responses to water stress duration, Pinot noir appeared to be less affected than Riesling to reduced water-holding capacity. Medrano et al. (2003) in a ten year study on the physiology of two Spanish grapevine cultivars Tempranillo and Manto Negro grown under field conditions observed that the cultivar Tempranillo performed better under moderate irrigation regime as it gave higher yield than the cultivar Manto Negro. In mandarin, DI treatment significantly decreased the production on Carrizo rootstocks in 2002 (34% reduction in fruit mass) and 2003 (85% reduction in fruit number), whereas DI reduced yield of trees on Cleopatra in the year 2003 only by decreasing 54 per cent of the fruit number (Romero et al., 2006). The decrease in yield was greater for trees raised on Carrizo (81%) than that on Cleopatra (56% reduction). The studies on the effect of different irrigation levels (full irrigation, deficit irrigation, partial rootzone drying and no irrigation) in two grapevine varieties Moscatel and Castelao revealed that the higher berry yield was obtained in cultivar Moscatel than Castelao when subjected to water stress conditions (Chaves et al., 2007). Klamkowski and Treder (2008) studied the response to drought stress on three strawberry cultivars Elsanta, Elkat and Salut and observed that under drought stress conditions the losses in yield in response to drought treatment were 38 per cent for Elkat, 29 per cent for Salut and 26 per cent for Elsanta cultivar and concluded that the cultivar Elsanta was the most drought tolerant, as reflected by higher yield parameter under drought stress than the remaining two cultivars. In olive cultivars Leccino and Cippressino, soil moisture had a positive correlation with fruit yield (Singh and Sharma, 2010) SOIL MOISTURE Layne et al. (1994) studied the effect of ground cover (temporary cover and permanent sod) and irrigation treatments in three cultivars of peach namely, 11

32 Garnet Beauty, Harbrite and Canadian Haromny in an orchard established on Fox sand in 1980 and observed that the soil water content in the top 130 cm was similar in non-irrigated and trickle-irrigated plots except during the growing season (May to September). Total soil water was lowest in non -irrigated plots that had permanent sod strips in the row middles and fell below the permanent wilting point for 11 months or more in summer but not at depths below 130cm. Total soil water availability under grapevine (Vitis vinifera) canopies of cultivars Tempranillo (widely grown in Spain) and Manto Negro (a Majorcan variety with a longer growth period showing higher yield stability under drought) was and l m -2 in the non- irrigated plants in the year 1997 and 1999, respectively, while the irrigated plants had 397 and l m -2 of total soil water content in the year 1997 and 1999, respectively (Escalona et al., 2003). In a study on olive cultivars Frantoio and Leccino, the experimental trees received different deficit irrigation treatments viz. a seasonal water amount equivalent to 33, 66 and 100% of Etc from the beginning of pit hardening to early fruit veraison and non-irrigated control and it was noted that the volumetric soil water content in the top 140 cm layer of soil of rain-fed controls during the irrigation season of four experimental years was more in cv. Frantoio than in Leccino and the cv. Frantoio achieved the highest crop production per unit of water consumption in response to different deficit irrigation treatments (D andria et al., 2009). Zegbe and Behboudian (2008) observed that the volumetric soil water content alternatively increased or decreased during the growing season as irrigation was shifted from the wetted side to the drying side of the tree row of Pacific Rose TM apple. The severe water stress substantially reduced the soil water in Monastrell Red wine grapevines grafted onto 1103 Paulsen rootstocks (Romero et al., 2010) CANOPY TEMPERATURE Lakso (1990) suggested that the large round leaves of kiwifruit do not exchange heat efficiently with the bulk air unless there is significant air movement and are likely to have significant temperature increases under reduced stomatal conductance (g s ). Grisafi et al. (2004) found that among three different 12

33 olive cultivars viz; Biacolilla, Cerauola and Nocellara del Belice, the cultivar Biancolilla had the best tolerance to high temperature and drought ANATOMICAL AND PHYSIOLOGICAL CHARACTERISTICS ANDWATER RELATIONS Water constitutes major proportion of the fresh weight the most plants. In plants, water performs a number of functions which show different sensitivities to water stress. The water moves from the soil, into the roots and up to the leaves in response to gradients in water potential (ψ), which is a measure of free energy per unit volume of water. When most of the water passing through the plant is used in transpiration (particularly in sunny weather), the flow rate is linearly proportional to the gradient in ψ between soil and leaf, ψ (Buwalda and Smith, 1990). However, most studies of water relations of kiwifruit vines have tended to focus on the impact of water stress on vine production and to identify criteria for defining irrigation requirements (Judd and McAneney, 1987) Stomatal studies Studies have shown that water deficit leads to an increase in stomatal density (Yang and Wang, 2001; Zhang et al., 2006), and a decrease in stomatal size (Spence et al., 1986) indicating this may enhance the adaptation of plant to drought (Spence et al., 1986; Martinez et al., 2007) Stomatal size Eris and Soylu (1990) in comparative study of fifteen Turkish grape cultivars, Kozak Beyazi, Siyah Razaki, Cavas, Amasya, Muskule, Hafizali, Sultani Cekirdeksiz, Tarsus Beyazi, Yapincak, Balbal, Erenkoy Beyazi, Pembe Gemre, Okuzgozu, Iskenderiye Misketi and Buca Razakisithe, for their adaptation to drought conditions observed that the stomatal length and width of these cultivars were different. The cultivar Muskule recorded the maximum stomata length and width while, the cultivar Erenkoy Beyazi had the minimum values of stoma length and width. Gucci et al. (2002) observed that the olive cultivars Frantoio and Leccino when subjected to water stress treatments (withholding irrigation for four weeks), resulted in stomatal size reduction, 13

34 however, the stomata of Frantoio were larger and more open than those of Leccino. Different effects of abiotic factors on stomatal size may depend on plant species/ varieties (Liu et al., 2006). Sanjeev (2006) observed that the plants of Flemish Beauty cultivar of pear grafted on Quince C and Quince A rootstocks had higher stomatal pore width in comparison to those on other rootstocks and were more affected by water stress in comparison to those grafted on BA 29 and Kainth seedling rootstocks. In a study on the response of eleven different olive cultivars viz. Moraiolo, Cornicobra, Pendolino, Coratina, Canino, Frontoio, Hojiblanca, Manzanilla, Gordal Sevilana, Cipressino and Leccino to water stress, the maximum stomatal length was observed in cv. Gordal Sevilana (15.57 µm) and the minimum (14.15µm) in cultivar Manzanilla (Kumar, 2010). The width of stomata was higher in Gordal Sevilana trees (11.06 µm) and the lower stomatal width was noticed in cultivars Canino, Manzanilla and Cipressino Stomatal density In an experiment on the fifteen Turkish grape cultivars, Kozak Beyazi, Siyah Razaki, Cavas, Amasya, Muskule, Hafizali, Sultani Cekirdeksiz, Tarsus Beyazi, Yapincak, Balbal, Erenkoy Beyazi, Pembe Gemre, Okuzgozu, Iskenderiye Misketi and Buca Razakisi, for their adaptation to drought conditions, the maximum number of stomata per unit area was observed in Pembe Gemre and the minimum in Balbal cultivar (Eris and Soylu, 1990). The cultivar Balbal was found to be more drought tolerant than other cultivars. Bosabalidis and Kofidis (2002) noted a 49.9 and 55.2% increase, respectively in stomatal density of abaxial surface of leaves for two varieties of olive, Mastoidis and Koroneiki under water deficit. Bacelar et al. (2006) reported that under the low water conditions, the olive cultivars Cobrancosa and Madural leaves showed a higher stomatal density than the cultivar Verdeal Transmontanas. Olive plants grown under drought conditions (by withholding water during one month until the soil almost reached the wilting point) showed a significant increase in the number of stomata (Guerfel et al., 2009). Among eleven different olive cultivars viz., Moraiolo, 14

35 Cornicobra, Pendolino, Coratina, Canino, Frontoio, Hojiblanca, Manzanilla, Gordal Sevilana, Cipressino and Leccino, the maximum stomatal density was observed in cv. Leccino (31.34/0.04mm 2 ) followed by Hojiblanca (30.17/0.04mm 2 ) and the minimum stomatal density(25.09 /0.04mm 2 ) was found in Gordal Sevilana (Kumar, 2010). Ennajeh et al. (2010) observed that in olive cv. Chemlali the stomatal density in leaves increased by 25% in comparison to 7% for Meski leaves during drought treatment, which could also enhance the external supply of CO 2. Boughalleb and Hajlaoui (2011) o bserved the olive cultivar Zalamati showed a significant increase in stomatal density than the cultivar Chemlali under water stress conditions Leaf water potential Leaf water potential ( ψ), determined by means of a pressure chamber (Scholander et al., 1965), corresponds with soil moisture and leaf gas exchange (Williams and Araujo, 2002) and may be a useful biological measure of grape vine water status that would enable varietal comparison in response to water stress independent of growing region. Leaf water potentials decreased with higher transpiration rates in citrus (Camacho et al., 1974). Gucci et al. (1993) observed that leaf ψ w of potted kiwifruit cv. Hayward vines decreased rapidly as water was withheld. By the 4 th day of stress, predawn ψ w was and MPa during the 1 st and 2 nd drought cycle, respectively. Levels of maximum stress were reached one day later when ψ w dropped to and M Pa, respectively. At maximum levels of stress, differences between ψ w of irrigated and stressed vines were less pronounced when measured at midday ( MPa) than at predawn ( MPa). Recovery of predawn ψ w was achieved within 10 h from re-watering. Gucci et al. (1997) reported that A. deliciosa does not demonstrate low midday leaf water potential values under water deficit as effective stomatal closure allows water conservation. Chartzoulakis et al. (2002) reported that the water stress affected avocado cultivars to a different degree, the cultivar Hass seems more affected by water stress, since at the same RWC, turgor potential was lower than that of Fuerte. A 15

36 reduction of only 10% of RWC from saturation (99%) to 89% resulted in a decrease of approximately 0.9 MPa for avocado cultivars Fuerte and 1.2 MPa for Hass in Ψ. The turgor (P) component accounted for the major part of this reduction (77% for Fuerte and 90% for Hass ), while Ψ π (osmotic potential) declined by only 64% for both cultivars. Predawn water potential (C) in waterstressed plants remained in both cultivars at control levels (-0.6 up to -0.7 MPa) for the first 5 days after withholding water and then declined to MPa in Fuerte and MPa in Hass on day 12. Among three almond cultivars Ferragnes, Francoli and Glorieta, the cultivar Francoli showed maximum reduction (-4.28 MPa) in leaf water potential under water stress conditions, which was attributed to some tolerance mechanisms (De Herralde et al., 2003). However, the cultivar Glorieta was most sensitive to water stress since, it was unable to recover water potential level up to that of control level after a week on re-watering. Thakur (2004) performed an experiment on the use of easy and less expensive methodology to rapidly screen fruit crops for drought tolerance and reported that the xylem water potential lowered down significantly (i.e times) in leaves of stressed plants of olive in comparison to water potential in leaves of unstressed plants. The lesser decline in water potential indicated that the variety was capable of maintaining higher internal water status and performed better at the advent of water stress. Satisha et al. (2007) reported that grape rootstocks Dogridge and Salt Creek performed better at 50 per cent moisture stress through maintenance of leaf turgidity as indicated by higher RWC and water potential attributing to better osmotic adjustment. Chaves et al. (2007) observed that the full irrigated grape vines of cultivars Castelao and Moscatel maintained high predawn leaf water potential throughout the growing season. The minimum values of ψ pd was measured in middle August in 2002 (the driest year), attaining MPa for Moscatel and MPa Castelao. While non-irrigated vines showed a progressive decline in ψ pd from July onwards and the two deficit irrigation treatments (PRD and DI) had ψ pd values intermediate between FI and NI. In Castelao, ψ pd of PRD vines was significantly higher than in DI. The ψ pd of Castelao NI vines at middle August 16

37 reached lower values ( MPa) than those of NI in Moscatel ( MPa). Nadal and Vernet (2010) studied the effect of deficit irrigation on four -year old Vitis vinifera cv. Syrah grafted on 41 B and 140 Ruggeri rootstocks and observed that under deficit irrigation, 41 B grew less and had a lower leaf water potential. They showed that the leaf water potential could be used as an indicator of the efficacy of irrigation. Boughalleb and Hajlaoui (2011) observed that the leaf water potential and leaf relative water content (LWC) of the two olive cultivars decreased with increasing water stress. The cultivar Zalmati showed higher values of leaf relative water content and lower values of Ψ LW than Chemlali, in response to water deficit, particularly during severe drought stress. Medeiros et al. (2012) observed the response of two genotypes 13-CPA and 14- CPA of Barbados cherry to drought stress and observed that the severe water deficit ( irrigation at 25 % of FC) treatment resulted in reduction of pre-dawn and midday leaf water potentials only in genotype 14-CPA Stomatal resistance Reynolds and Naylor (1994) observed that the vines of Pinot noir and Riesling grapes showed reduced leaf stomatal conductance with increased water stress duration, but soil water increased. Stomatal resistance provides sensitive comparison or indicates the degree of stress in plants under adverse conditions (Gunes et al., 1996). Dichio et al. (2006) reported that the stomatal conductance and net photosynthetic rate declined with the increasing drought conductance and net photosynthetic rate declined with the increasing drought stress in olive trees. Sharma and Sharma (2008c) observed that in Flemish Beauty pear raised on different rootstocks exhibited the decreased stomatal conductance with drought stress treatment however, pear plants raised on Kainth rootstocks had highest stomatal conductance followed by plants on BA 29 rootstocks while, the lowest stomatal conductance was observed in plants raised on Quince C rootstocks. This decrease in stomatal conductance caused a reduction of intercellular CO 2 and photosynthetic rate. The investigation on the physiological and morphological responses of two almond cultivars, Princesse and Tuono to drought stress 17

38 revealed that the stomatal resistance was higher in cv. Tuono than the cv. Princesse under drought stress conditions (Gikloo and Elhami, 2012) Transpiration rate Water stress caused a decrease in transpiration, an increase in foliage temperature and closure of stomata in peach (Tan and Buttery, 1982). Xiloyannis et al. (1988) observed that the plants of kiwifruit cv. Hayward showed a sudden drop in transpiration at soil water levels of approximately 50 per cent of available water. Buwalda and Smith (1990) observed that A. deliciosa var. deliciosa Hayward had higher transpiration rate with poor stomatal control. Chartzoulakis et al. (1997) reported that A. deliciosa did not demonstrate low midday leaf water potential values under water deficit as effective stomatal closure allowed water conservation. Reynolds and Naylor (1994) reported that the stomatal conductance and transpiration of Pinot noir and Riesling grapevines decreased linearly with the increasing level of water stress duration on two of four sampling dates. However, control vines had the highest transpiration rates on one of four dates for Pinot noir and on two of four dates for Riesling. Ghaderi et al. (2007) observed that the water stress in two cultivars of grape, Rashe and Khoshnave resulted in the depletion of soil water content, which consequently decreased the transpiration rate from 6.58 to 0.45 and 6.95 to 0.38 (mmol m -2 s -1 ) in Rashe and Khoshnav grape, respectively and concluded that the cultivar Rashe had higher resistance to water stress than cultivar Khoshnav. Ennajeh et al. (2010) observed that under water deficit conditions, olive cv. Chemlali maintained lower transpiration rate compared to Meski Photosynthetic rate The onset of stress may initially cause a loss of cell turgor in citrus (Kriedemann and Downton, 1980), which in turn reduced gas exchange and leaf elongation, since both are turgor dependent processes (Bradford and Hsiao, 1982). Schultz (1996) in a comparative study on two different grapevine cultivars from different geographic origin, Grenache of Mediterranean origin 18

39 and Syrah of mesic origin showed that the cultivar difference played role in adaptive responses to water deficit. Photosynthesis was more sensitive to water stress in Greenache than in Syrah. Chlorophyll fluorescence measurements also showed higher sensitivity of the former cultivar to water stress than the latter. In drought stressed grapevines, fully expanded sun-exposed leaves usually show large variation in photosynthesis both on a seasonal and a diurnal basis (Escalona et al., 1999, Flexas et al., 1999). Iacono and Peterlunger (2000) observed that rootstock -scion interaction may affect drought tolerance in Vitis vinifera cultivars. Under well-watered conditions, Rhine Riesling (RR) when used as a rootstock negatively affected net photosynthesis (Pn) of both H26 and H8, whereas, Muller Thurgau (MT) reduced Pn of only H8. Rhine Riesling as a scion did not suffer due to any rootstock influence on Pn. The changes in Pn for H8 when grafted on MT and RR were mainly due to reduction in carboxylation efficiency. Graft combinations (H26/RR, MT/H26 and MT/H8) showed different behavior under water stress conditions. The highest levels of photosynthetic rate were observed in MT/H8 while, the reduced photosynthetic performance was recorded in majority of grafted vines. Chartzoulakis et al. (2002) reported that the avocado cultivar Hass had higher photosynthetic rates (Pn) than Fuerte at the same leaf water potential. The higher stomatal conductance (gs) exhibited by Hass at the same leaf water potential could explain the apparent contradiction. The photosynthesis is inhibited by reducing the diffusion of CO 2 to the chloroplast, both by stomatal closure and changes in mesophyll structure, which decreases the conductance to CO 2 diffusion within the leaf. The exposure of three almond cultivars Ferragnes, Francoli and Glorieta to water stress conditions resulted in the reduction in photosynthetic rate (De Herralde et al., 2003). In Ferragnes and Francoli cultivars, the recovery process was up to the control level; however, Glorieta cultivar recovered its 50 per cent of net photosynthetic rate and 65 per cent of stomatal conductance, with respect to fully irrigated control. Ennajeh et al. (2010) studied the comparative impacts of water stress on the leaf anatomy of drought- resistant and drought-sensitive olive cultivars and observed that under 19

40 water deficit conditions, Chemlali maintained higher rates of photosynthetic assimilation compared to Meski Chlorophyll content Among six grape rootstocks, Dogridge, Salt Creek, 1613-C, 1616-C, 1103-P and SO4, the chlorophyll content was highest in 1103-P and lowest in SO4 under water stress treatment(0.3 bar) in comparison to water stress at 0.5 and 0.7 bar (Kadam et al., 2005). The chlorophyll content get decreased under low water conditions in different olive cultivars viz., Cobrancosa, Madural and Verdeal Transmontana from 7.40, 5.94 and 6.91 to 5.87, 5.79 and 5.46 mg dm -2, respectively (Bacelor et al., 2006). The decrease of chlorophyll content is a typical symptom of oxidative stress and may be the result of chlorophyll degradation or be due to chlorophyll synthesis deficiency together with changes of thylakoid membrane structure (Sm irnoff, 1993). The severe water stress reduced the chlorophyll content in Monastrell red wine grapevines grafted onto 1103 Paulsen rootstock (Romero et al., 2010). Boughalleb and Hajlaoui (2011) observed that the olive cultivar Zalamati showed higher chlorophyll content than Chemlali under severe water stress conditions. Ghaderi and Siosemardeh (2011) noted significant reduction in chlorophyll content of leaf under severe drought stress (25% of FC) compared to control (75% of FC) and mild drought stre ss (50% of FC) in strawberry. The cultivar Kurdistan showed higher chlorophyll content under all conditions. Shaheen et al. (2011) in a comparative study on five olive cultivars Picual, Koroneiki, Manzanillo, Coratina and Eggizi Shami recorded the highest significant value of chlorophyll in cv. Koroneiki (83.4 and 81.8%, respectively in 2009 and 2010), while Manzanillo recorded the lowest values of 72.8 and 73.3%, respectively in both the seasons and concluded that Koroneiki cultivar as highly drought tolerant. Miraghaee et al. (2012) reported that kiwifruit cv. Hayward grown in Sahneh region had higher values of leaf chlorophyll and chlorophyll b than those kiwifruit vines grown in Ramsar region of Iran. This variation was attributed to different climate, wherein plants had to encounter a drought stress under low humidity of Sahneh region. In almond, the higher chlorophyll content 20

41 was observed in cultivar Tuono than the cultivar Princesse under drought stress conditions (Gikloo and Elhami, 2012) Chlorophyll stability index (csi) In a study in grape (Patil et al., 2005), fifty four cultivars were screened for their drought tolerance based on chlorophyll stability index (CSI), in which CSI was found variable from to per cent and cultivars like Athens, Buckland s Sweet Water, Foster Seedlings, Jose Beli, Oval White, President and Queen Gold were found significantly more tolerant to drought over the other cultivars. Thakur (2004) observed that the high chlorophyll stability index ( CSI) corresponds to low drought tolerance in strawberries. Based on this Blackmore, cultivars Catskill and Howard showing the lowest values (approximately 10%) were categorized as relatively highly drought tolerant; Teoga and Shastha as moderate ones and Torrey (CSI value 21.5%) as the most sensitive to drought. In grape, fifty four cultivars were screened, based on CSI for their drought tolerance and CSI was found variable from to per cent. Based on these observations, cultivars Athens, Buckland s Sweet Water, Foster Seedlings, Jose Beli, Oval White, President and Queen Gold were rated significantly more tolerant to drought over the other cultivars (Patil et al., 2005). Kadam et al. (2005) observed that among six grape rootstocks namely, Dogridge, Salt Creek, 1613-C, 1616-C, 1103-P and SO4, the chlorophyll stability index was lowest in 1103-P and highest in SO4. However, CSI in leaves of various rootstocks invariably decreased significantly with increasing water stress. Sanjeev (2006) observed that plants of pear cv. Flemish Beauty showed maximum chlorophyll stability index grafted on Kainth rootstocks, followed by those on BA 29 rootstocks. The CSI was however, observed the lowest in plants grafted on Quince C rootstocks Proline content Proline, though constitute only less than 5 per cent of total pool of free amino acids in plants, yet under the various forms of stresses, the concentration can increase up to 80 per cent of the amino acid pool (Stewart and Bewley, 21

42 1980). Hanson and Hitz (1982) r eported that proline content increases remarkably in response to stress in mesophytes. The accumulation of free proline under water stress significantly increased the amount of bound water and hence could be a useful index for selecting drought tolerant varieties (Kapuya et al., 1985). An important role in drought resistance has been attributed to proline accumulation (Sivaramakrishnan et al., 1988; Venekamp 1989), however, it is still not clear whether accumulation of proline can provide any biochemical adaptation for plants during water deficit (Navari -Izzo et al.,1990; Sundaresan and Sudhakaran, 1995). Ramteke and Karibasappa (2005) in a study on twenty genotypes of grapes observed that under water stress, the proline accumulation was significantly higher V. longii, Arka Shweta, Concord, de Grasset, Thompson Seedless, Muscat, SO 4, Dog Rigde, Amtsir, Ramsey and Red Globe in comprasion to the remaining genotypes. Sharma and Sharma (2008 a) observed that the pear plants of cultivar Flemish Beauty raised on BA 29 and Kainth rootstocks showed higher per cent increase in leaf proline content at bar soil moisture tension than those on Pyrus serotina, Quince A and Quince C rootstocks. Ber (Ziziphus mauritiana) showed varietal variation in proline concentration under water stress (Kala and Godara, 2011), wherein the maximum proline was recorded in Gola followed by Umran and Kaithli cultivars following withholding irrigation for different period. Miraghaee et al. (2012) reported that kiwifruit cv. Hayward grown in Sahneh region had higher values of leaf proline than those kiwifruit vines grown in Ramsar region of Iran. Ghaderi and Siosemardeh (2011) observed that in strawberry cultivars Kurdis tan and Selva, the proline content increased significantly under severe drought stress (25% of FC). Interaction between drought treatments and genotype showed that proline levels were higher in Kurdistan than in Selva at severe drought stress (25% of FC). A positive correlation between magnitude of free proline accumulation and drought tolerance has been suggested as an index for determining drought tolerance potential of cultivars. In different olive cultivars, the proline accumulation were increased gradually with increasing level of drought stress, however, the highest proline accumulation was obtained with cultivar Egazi 22

43 Shami when subjected under severe stress conditions in comparison to normal irrigated plants (Shaheen et al., 2011). A study on in vitro screening of almond genotypes for drought tolerance however, revealed that the proline accumulation in the leaves is a general response to drought stress and its concentration probably is not related to drought tolerance of the plant (Karimi et al., 2012) Free amino acids Free amino acid (FAA) are known as important constituents of osmoregulation in leaves of many species (Morgan, 1984) and their rise during slowly developing stress is correlated with increasing drought tolerance of the plant. Sircelj et al. (1999) observed that the free amino acid content increased in leaves of drought stressed plants of two apple cultivars Elstar and Jonagold Wilmuta. The most pronounced difference between control and stressed leaves with respect to Orn, Arg and Pro content was found in cv. Elster, whereas, Pro and Arg contents were more variable in cv. Jonagold Wilmuta. Zhang and Archbold (1993) compared the response of two different species of strawberry i.e. Fragaria chiloensis (FC) BSP14 and F. virginiana (FV) NCC85-13V selection to water deficit stress and observed no changes in leaf amino acids concentration for FV throughout the experiment, while the leaf amino acid concentration of stressed FC plants was 2.1, 2.7 and 2.8-fold higher than that of the controls at the end of wilting cycles 1, 2 and 3, respectively. These two species differ in drought resistance; FC was found as drought resistant while FV was susceptible to drought. Sanjeev (2006) observed that the level of free amino acids was more in Flemish Beauty pear plants raised on Kainth and BA 29 rootstocks at soil moisture tension level of bar, in comparison to those on Quince A and Quince C rootstocks. Kala and Godara (2011) observed that the minimum free amino acid in leaves increased with increased period of moisture stress in ber cultivars Gola, Umran and Kaithli, but the increase was more pronounced in Gola followed by Umran Relative water content Schultz (1996) in an experiment on water relations and photosynthetic responses of two grapevine cultivars of different geographical origin during water 23

44 stress observed that the cultivar Grenache was more sensitive to water deficit than Syrah. As at low relative water content, turgor loss occurred in Syrah, which allow this cultivar to maintain stomatal opening at lower water potential and to better exploit the soil water reserves. Thakur (2004) rated the Cornicobra olive as relatively most tolerant to drought as a minimum decline in RWC of per cent from 8 to 48 hour of water stress was observed in this cultivar, this followed by Aglandeau, Frontoio, Pendulino (intermediate) and the cv. Coratina, was the most sensitive because of maximum decline in RWC was registered in this cultivar following imposition of water stress. The varietal differences in relation to relative water content were clear and significant. Bacelar et al. (2006) observed that in olive cultivars Cobrancosa, Madural and Verdeal Transmontana, the RWC under well watered conditions was 92.7 per cent, 90.6 per cent and 93.6 per cent which get reduced to 82.2, 81.6 and 80.8 per cent, respectively under low water conditions. Two-year-old plants of olive ( Olea europaea L.) varieties Koroneiki, Meski grown in pots in greenhouse, when subjected to three drought treatments viz., mild, moderate and severe drought stress, the relative water content of all the varieties decreased with increasing levels of drought stress, however, Koroneiki showed lower values of RWC than the Meski, particularly during severe drought stress (Boussadia et al., 2008). Ghaderi and Siosemardeh (2011) studied the response of two strawberry cultivars namely, Kurdistan and Selva to drought stress and observed that plants subjected to water deficits had significantly lower RWC than the controls (75% of FC) averaging 7% in mild drought stress (50% of FC) and 31.5% of FC in severe drought stress (25% of FC). The RWC was higher in Kurdistan than in Selva. Rostami and Rahemi (2013) conducted an experiment for the screening of drought tolerance in caprifig varieties Daneh Sephid, Pouz Donbali, Shah Anjir and Khormaei and observed that among these four male genotypes Shah Anjir, and Khormaei were able to preserve the highest relative water content during the drought period. 24

45 Xylem development Plants can respond to water stress at morphological, anatomical and cellular levels by modifications that allow them to avoid the stress or increase tolerance ( Bray, 1997). The reduction in xylem vessel density and diameter of individual xylem vessels offer more resistance to water movement through conductive tissues to the terminal parts of plants (Frakulli and Voyiatzis, 1999). Vessel size varies with variety and the larger size often resulted in higher sensitiveness to embolism under drought conditions (Chouzouri and Schultz, 2005) Number of primary xylem vessels Colin et al. (2005) observed in a study on five Mexican peach cultivars, (Jalatzingo, Misantla, Sombrerete, Tulancingo and Temascaltepec) observed that the cultivars from drier environments (Tulancingo and Sombrerete) had larger size and smaller frequency of xylem vessels as well as low xylem and phloem percentage in shoots. The cultivars from areas of little drought stress (Jalatzingo) showed the opposite characteristics. Plants of pear cultivar on Kainth and BA 29 showed less reduction xylem vessel diameter compared to trees on the other rootstocks under water stress conditions (Sharma and Sharma, 2008b). Kumar (2010) in a study on eleven different cultivars of olive viz.; Moraiolo, Cornicobra, Pendolino, Coratina, Canino, Frontoio, Hojiblanca, Manzanilla, Gordal Sevilana, Cipressino and Leccino observed significantly higher number of primary xylem vessels in cv. Gordal Sevilana (154.0) and significantly lowest in cv. Canino (139.4) and Cipressino (139.7) Length of secondary xylem vessels In pear, development of secondary xylem vessels under drought stress was decreased by rootstocks ( Sharma and Sharma, 2008b). However, plants on Kainth and BA 29 rootstocks showed less reduction in width of secondary xylem at higher soil moisture tensions compared to those raised on Quince C and Quince A rootstocks. Among eleven different cultivars of olive viz.; Moraiolo, Cornicobra, Pendolino, Coratina, Canino, Frontoio, Hojiblanca, Manzanilla, Gordal Sevilana, Cipressino and Leccino, the width of secondary xylem was 25

46 recorded maximum in Gordal Sevilana (59.1 µm) which got reduced to 57.4 µm in the next year in response to water stress treatment. However, the minimum width of secondary xylem was noticed in Cipressino (53.5 µm) which got reduced to 52.4 µm in the next year after imposition of drought stress (Kumar, 2010) Endogenous hormones There are two mechanisms that appear to operate for stomatal closure in response to water stress: active control, which might operate through increasing abscisic acid and reducing cytokinin and the second one, is inactive control, called hydro-passive and performs in the absence of hormones (Levitt, 1980) Cytokinin content Cytokinins (CKs) antagonize many physiological processes induced by water stress, mainly those mediated by ABA. Well known is the reversal of ABA-induced stomatal closure. Further, water stress usually accelerates leaf senescence, and in contrast, cytokinins delay leaf senescence (Soejima et al., 1992; Catsky et al., 1996; Naqvi, 1999). Cytokinins promote cell division and, acting both in synergy and antagonism with other plant hormones, thereby influence a wide range of events during plant growth. The major portion of CKs are produced in meristematic regions in the root system and transported via xylem to the shoot. These CKs, along with the locally synthesized CKs, control development and senescence of the whole plant. Cytokinins promote leaf expansion, accumulation of chlorophyll and conversion of etioplasts into chloroplasts, and delay leaf senescence (Pospisilova et al., 2000). The xylem exudate and/or leaves of stressed plants usually exhibit reduced CK content and activity. The response is usually rapid and CK activity returns to a normal level after a release of stress (Naqvi 1994, 1995). Stoll et al. (2000) observed a reduction in zeatin and zeatin-riboside concentrations in roots, shoot tips and buds by 60, 50 and 70%, respectively under the partial root zone (PRD) drying treatment in grapevine cultivars Sultana grown in pots and Cabernet Sauvignon grown in field in comparison to fully irrigated control. Satisha et al. (2006) applied three levels of moisture stress to 26

47 the five grape rootstocks namely, Dogridge, 1613 C, Salt Creek, St. George and Vitis champinii clone (VC Clone) and observed that the cytokinin contents were comparatively lower in the rootstocks Dogridge and Salt Creek and higher in 1613 C and St. George at 50 per cent stress. Pear cv. Flemish Beauty raised on Kainth (Pyrus pashia) and BA 29 rootstocks showed less reduction in cytokinin in comparison to those raised on Pyrus serotina seedlings, Quince A and Quince C rootstocks when subjected to different levels of water stress (Sharma and Sharma, 2008a). Beis and Patakas (2010) observed that the cytokinin content in leaves of grape cv. Mavrodafni was lower when compared with the cultivar Savatiano under deficit irrigation (DI) regimes Abscisic acid As soil water availability falls following the cessation of irrigation, abscisic acid is synthesized in the drying roots and transported to the leaves in the transpiration stream (Loveys et al., 1999). Vines of Vitis vinifera cv. Muller Thurgau raised onto three hybrid rootstocks (H1, H8, H26) along with ownrooted plants of V. vinifera and own-rooted hybrids were tested in pots during 7 and 14 days of water stress (i.e. daily water supply reduced to 66% of well - watered plants) and it was observed that with the increase in water deficit there was a corresponding increase in the concentrations of abscisic acid (ABA), that was 15.4, 22.6 and 38.6 mg g -1 of dry weight for well watered conditions, 7 and 14 days stressed plants, respectively (Iacono et al.,1998). The rootstocks of V. vinifera on hybrid showed similar ABA contents in leaves as V. vinifera on its own roots, however, own rooted hybrids showed lower value of ABA content in leaves. Abscisic acid plays important roles in stomatal regulation (Gibson et al.,1991; Chen et al., 2003; Sirichandra et al., 2009), gene expression (Alamillo and Bartels, 2001; Wheeler et al., 2009) and metabolic changes (Agarwal et al., 2005). Grapevine cv. Sultana grown in pots and cv. Cabernet Sauvignon grown in field showed a 10-fold increase in ABA concentration in the drying roots, but ABA concentration in leaves of grapevines under PRD only increased by 60% compared with the fully irrigated control (Stoll et al., 2000). Satisha et al. (2006) applied different levels of water stress to five grape rootstocks and observed 27

48 higher ABA content in Dogridge and Salt Creek and lower ABA content in 1613 C and St. George at 50 per cent of water stress. ABA can enhance stress tolerance (Seki et al., 2007; Parent et al., 2009) as a result of its endogenous concentration (Nagel et al., 1994; Wang et al., 2007). Soar et al. (2006), observed that the higher sensitivity of stomata in grape genotype Grenache was due to the higher concentration of ABA in the xylem sap as compared with the genotype Syrah. They provided evidence of a midday increment of the expression of key genes involved in the ABA biosynthetic pathway, significantly higher in the leaves of Grenache than in Syrah in response to atmospheric moisture stress. ABA improves tolerance in kiwifruit, reducing membrane permeability and enhancing the activities of antioxidant enzymes, e.g., peroxidase (POD), catalase (CAT), superoxide dismutase (SOD), ascorbate peroxidase (APX), and glutathione reductase (GR) (Wang et al., 2010). Sanjeev (2006) observed that pear trees of cultivar Flemish Beauty raised on different rootstocks when irrigated at 10 bar accumulated significantly more ABA content in leaves and the plants on Quince C rootstocks had higher concentrations of ABA while, the plants on Kainth rootstocks showed lower ABA content at the same level of moisture tension Leaf nutrient status Deficit irrigation reduces the transport of mineral ions through soil to the roots and through the plants. The demand for minerals by shoots and roots get changed as a result of drought stress. Drought stress modifies the uptake of mineral ions by the roots and the deficiencies or accumulation of ions resulted in disruption of metabolism in plants. During drought, the growth rate may be reduced to the extent, so that plant mineral content may be relatively stable (Pitman, 1981). Nitrate contributes to osmotic adjustment (Talouizite and Champigny, 1988), particularly under low light when carbohydrates and organic acids are in short supply (Blom- Zandstra and Lampe, 1985). During drought, the phosphate ion is likely to be unavailable to plants as it is tightly absorbed onto clay particles, thus only a small proportion of total soil phosphate is available in soil solution. The diffusion coefficient is 10 4 to 10 7 times lower than that of potassium, nitrate and ammonium. Potassium plays a key role in stomatal 28

49 opening. A reduced supply of potassium therefore reduces stomatal conductance to CO 2 much more than the internal conductance (Terry and Ulrich, 1973) because it get lost from the guard cells at low water potentials (Ehret and Boyer, 1979) Nitrogen Sanjeev (2006) observed that under increased water stress, leaf N contents were higher in Flemish Beauty pear plants raised on Kainth seedling rootstocks as compared to those on clonal rootstocks. Shaheen et al. (2011) observed a significant reduction in leaf N per cent due to increasing drought stress in two seasons, 2009 and 2010 in olive transplants of cultivars Picual, Koroneiki, Manzanillo, Coratina and Eggizi Shami. However, leaf N levels varied among the cultivars, wherein, the lowest nitrogen percentage was obtained in Eggizi Shami at irrigation with 25% from FC, while the highest was obtained with Koroneiki cultivar at the same moisture level Phosphorus In Flemish Beauty pear, water stress invariably decreased the leaf P content, however, rootstocks affected the leaf P levels significantly and it was found to be higher in plants raised on Kainth seedlings than those on Quince A and Quince C rootstocks (Sanjeev, 2006). In olive cultivars Picual, Koroneiki, Manzanillo, Coratina and Eggizi Shami, the P content in leaves was gradually decreased with decreasing water depletion from 100 to 25% from FC in two seasons (2009 and 2010), however, its content was significantly higher in Koroneiki cultivar when exposed to moderate drought stress (75% of FC) compared to other at the same moisture level (Shaheen et al., 2011) Potassium In Flemish Beauty pear, the concentration of leaf K decreased markedly with the onset of water stress, however, plants of Pyrus pashia and BA 29 rootstocks showed less reduction in the concentration of leaf K in comparison to those on Pyrus serotina, Quince A and Quince C rootstocks (Sharma and 29

50 Sharma, 2008a). The potassium content in leaves of olive cultivars Picual, Koroneiki, Manzanillo, Coratina and Eggizi Shami decreased gradually by decreasing water depletion from 100 to 25% from FC, however, among these cultivars, the K content was significantly higher in Koroneiki cultivar and lower in cultivar Eggizi Shami at moderate drought stress (75%) (Shaheen et al., 2011). In grapevine, the blade K concentration at veraison varied according to cultivar response to water deficit; the deficit irrigated vines had lower K in cv. Malbec, Petite Syrah, Viognier and Sangiovese; higher K in cv. Cabernet Sauvignon and Cabernet Franc, or similar potassium content in Grenache, Merlot and Lemberger as well- watered vines (Shellie and Brown, 2012) Calcium Romero et al. (2006) reported that trees on Cleopatra rootstock had significantly higher leaf Ca concentration than trees on Carrizo after three years of DI treatments. Sanjeev (2006) observed that the plants of Flemish Beauty pear plants when subjected to increased water stress showed decrease in the concentration of leaf Ca contents, however, those raised on Kainth rootstocks showed less reduction in leaf Ca level as compared to plants raised on other rootstocks. Leaf Ca content decreased with increasing drought stress in olive plants of cultivars Picual, Koroneiki, Manzanillo, Coratina and Eggizi Shami, however, Picual recorded the highest value (2.3%) of leaf calcium content while those of Eggizi Shami recorded the lowest value (1.6%) when their plants exposed to drought stress conditions (Shaheen et al., 2011) Magnesium Romero et al. (2006) reported that trees on Cleopatra rootstock had significantly higher leaf Mg and B concentration than trees on Carrizo rootstock after three years of DI treatments. Sanjeev (2006) observed that leaf Ca contents in Flemish Beauty pear plants decreased with the increase in the soil water stress, however, the plants raised on BA 29 rootstocks had higher leaf Mg when compared to those on Pyrus serotina, Quince A and Quince C rootstocks at the respective water stress levels (irrigated at -0.5 bar, -5.0 & bars). 30

51 2.1.6 PHYSICO-CHEMICAL CHARACTERISTICS OF FRUITS Drought stress has been shown to cause alteration in the chemical composition and physical properties of the cell wall (Peleman et al., 1989). Water stress affect the fruit shape as different parts of the fruit are metabolically more active at different stages of fruit development. There is more differential accumulation of soluble solids in fruit as a result of water stress condition (Mac Rae and Redgwell, 1990). Water stress in the second phase of kiwifruit growth, accelerated ripening processes resulted in earlier maturity in stressed fruit than the controls. The sucrose concentrations were higher in water stressed fruit at harvest, and the seed changed colour from white to brown approximately six weeks earlier than in control fruit (Pratt and Reid, 1974) Fruit size and weight In kiwifruit, there is a close link between fruit growth and vine water status (Judd et al., 1989), with even mild water shortage negatively affecting fruit growth (Prendergast et al., 1987). However, studies on varietal performance in kiwifruit with respect to fruit development under water deficit are lacking. Pereira and Couto (1997) studied the stem and fruit growth of Guava (Psidium guajava L.) cultivars Pirassununga Branca, Pirassununga Vermelha, Industrial de Montes Claros, Brune Branca, Tetraploide de Limeira and IAC-4 cultivars under soil water stress conditions and observed the heaviest fruit weight in Industrial de Montes Claros (78.5g) while, the lowest fruit weight was recorded in Tetraploide de Limeira (26.3 g) among these cultivars. The Berry weight of grapevine cultivar Moscatel (syn. Muscat of Alexandria - a white variety) was more affected under water stress conditions than that of a red variety, Castelao (Chaves et al., 2007). In olive cultivars Frantoio and Leccino, the deficit irrigation treatment resulted in more reduction in fruit diameter, fresh and dry weight of cultivar Leccino than Frantoio (D andria et al., 2009). Nadal and Vernet (2010) observed the deficit irrigation had a significant effect on two year old Grape cultivar Syrah grafted on 41 B and 140 Ruggeri rootstocks. However, there was more decrease 31

52 in berry fruit weight of vines raised on 41 B rootstocks in comparison to those on 140 Ruggeri rootstocks Fruit firmness Miller et al. (1998) observed no effects of water stress on flesh firmness in kiwifruit cv. Hayward. The mean firmness of the fruit was 1.2 kg F when assessments were made after cool storage. In a similar experiment conducted by Reid et al. ( 1996), Hayward kiwifruit harvested from vines exposed to a less severe drought stress were unaffected in size, however, higher fruit firmness was retained for 30 days longer in comparison to control (fruit harvested from fully irrigated vines). Tavarini et al. (2011) studied the effect of water stress on peach fruit cv. Suncrest raised on different rootstocks GF 677, Montclar and Penta and observed that the irrigation stress decreased the flesh firmness of fruits on GF 677 and Montclar more than those on Penta rootstock Total soluble solids Medrano et al. (2003) in their ten year study on the physiology of two Spanish grapevine cultivars Tempranillo and Manto Negro observed that the TSS content was significantly higher than in cultivar Tempranillo in response to moderate irrigation treatment. Romero et al. (2006) reported that the DI significantly decreased TSS contents if fruits from trees of mandarin raised on Carrizo, whereas TSS was increased in fruit from DI trees on Cleopatra. Chaves et al. (2007) observed that the grape cultivar Moscatel showed more increase in berry TSS content in comparison to Castelao when subjected to drought stress conditions Titratable acidity Santos et al. (2003) studied the effect of partial root zone drying on growth and fruit quality of field grown grapevines ( Vitis vinifera) varieties Moscatel and Castelao and observed that the watering had no significant effects on sugar accumulation in the berries but led to a favourable increase in titratable acidity, mainly in cv. Castelao. 32

53 Chaves et al. (2007) observed that among two grapevine varieties Moscatel and Castelao, the reduction in berry titratable acidity was significantly lower in Moscatel than Castelao in response to drought stress conditions. Nadal and Vernet (2010) observed that under deficit irrigation treatment, twoyear old Grape cultivar grafted on Syrah 41 B grew less vigorously and produced berries with higher acidity than those raised on 140 Ruggeri. The studies on the effect of water stress and different rootstocks namely GF 677, Montclar and Penta on the quality indices and nutritional characteristics of peach cv. Suncrest revealed that the irrigation stress resulted higher titratable acid contents in fruit from trees on GF 677 and Penta rootstocks than those on Montclar rootstocks (Tavarini et al., 2011) Sugar content The effects of water availability on soluble sugar content are dependent on the cultivar. The soluble sugar content of Grenache cultivar of grape decreased with water stress while, the Syrah cultivar showed no variation in sugar content at the same level of water stress (Schultz, 1996). Nadal and Vernet (2010) observed a decrease in sugar content in berries of grape vine of Syrah cultivar raised on 41 B rootstocks in comparison to those on 140 Ruggeri rootstocks. Navarro et al. (2010) observed that the in Clemenules mandarin grafted on Cleopatra and Carrizo rootstocks, the water deficit in early stages of fruit development resulted in more glucose, fructose and sucrose content for osmotic adjustment, and the reducing sugars in comparison to fruits on Carrizo rootstocks Ascorbic acid Ascorbic acid plays an important role in protecting the photosynthetic apparatus against the destructive effects of light and reactive oxygen species (ROS), however information on the influenced of water stress on fruit ascorbic acid metabolism is lacking. Sircelj et al. (1999) observed that ascorbic acid contents of leaves from the drought stress on in apple (Malus domestica Borkh.) cvs. Elstar and Jonagold Wilmuta raised on M9 rootstocks were variable. The ascorbic acid were increased in the leaves of stressed Jonagold Wilmuta cultivar, 33

54 on the contrary, ascorbic acid contents got decreased in the stressed cultivar Elstar compared to control of the respective cultivar. 2.2 EFFECT OF DEFICIT IRRIGATION AND IN SITU MOISTURE CONSERVATION ON FRUIT CROPS EFFECT OF DEFICIT IRRIGATION The information pertaining to the effect of deficit irrigation and in situ moisture conservation on different parameters in kiwifruit is few and inconclusive. The relevant available information in kiwifruit and other fruit crops pertaining to the present studies has been reviewed as under: VEGETATIVE GROWTH In kiwifruit, economic return is directly related to the vine size, which is strongly affected by availability of water (Judd and McAneney, 1987). Fruit trees under continuous readily available soil moisture conditions during the growing period make more total growth than the trees under limited supply of moisture (Goode and Ingram, 1971). Soil moisture affects almost every aspect of plant growth and development by modifying morphological and biochemical characteristics; however, the vegetative growth is the most sensitive plant parameter to water stress (Hsiao, 1973) Shoot growth Proebsting et al. (1981) stated that growth of fruit and vegetative parts was reduced by severe stress conditions in bearing sweet cherry and prune trees. Irving and Drost (1987) observed 37 per cent reduction in shoot growth of apple plants under water stress as compare to fully irrigated plant. Li et al. (1989) in a study on peach cv. Merrill Sundance raised on Rubira rootstocks observed that water stress imposed during the first and second phase of fruit development resulted in a significant reduction of shoot extension growth during the respective stress period. The total extension growth increment of all the new shoots on the previous season s shoot was reduced by about 25% in 1987 and of terminal shoots from 11 to 40% in However, there were no obvious differences in shoot growth during the second phase between the treatments 2 nd PWS (water stress during the second phase of fruit development) and 1 st + 2 nd PWS (water 34

55 stress during the first two phases of fruit development), nor between the control trees and the re-watered trees (treatment 1 st PWS). Chartzouolakis et al. (1993) in a trial on kiwifruit cultivar Hayward, imposed water stress by irrigating the plants with 100%, 85%, 65% and 40% of water need to reach field capacity in the soil and observed maximum shoot length in vines irrigated at 100 per cent field capacity, whereas it was 79 per cent less when irrigation was given at 65 per cent of field capacity. Further, the severe water stress imposed by irrigation at 40 per cent of field capacity reduced the plant height by per cent. However, the trunk radius was not affected when different amount of water was applied by different irrigation system in kiwifruit vines (Chartzoulakis et al., 1991). Ciordia et al. (1993) found that vegetative development of kiwifruit cultivar Hayward was decreased under dry soil moisture conditions. In this cultivar, drought condition even for a short period during the growing season induced dehydration of herbaceous parts, as a result of which vine growth was reduced (Monastra et al.,1994). Monastra et al. (1997) also reported reduction in vegetative growth of kiwifruit vines under water stress conditions. Poni et al. (1993) observed that in potted Pinot Noir grapevines shoot elongation was significantly reduced during the season only by pre-veraison water stress and this reduction was apparent all through the rest of the season. In Braeburn apples, holding up of irrigation during the early growing season caused great reduction in vegetative growth but late water stress did not exhibit any effect on vegetative growth (Kolili et al., 1996). Teng et al. (1999) observed that water stress conditions, particularly during the early growing season, caused a great reduction in vegetative growth of pear. Boland et al. (2000) reported that RDI reduced vegetative growth by up to 70% as measured by weight of summer pruning in peach Golden Queen. The water stress conditions resulted in 17.0 per cent and per cent reduction in the shoot length and intermodal length, respectively in grape cv. Tas-A-Ganesh grafted on Dogridge rootstock (Ramteke et al., 2001). The physiological reaction of a grape vine to water stress might affect growth and development of the shoots, leaves and fruit depending on the timing 35

56 and level of water stress during the season (Goodwin, 2002). Shellie (2006) observed that in grape cv. Merlot, annual trunk growth of vines under deficit irrigation was 20% and 40% less in the years 2003 and 2004, respectively than the vines under 100% ET c.. In grapevines, the water deficit though reduced the mass of root system slightly but reduced the mass of shoots markedly (Pire et al., 2007). Zegbe and Behboudian (2008) observed that the shoot growth was reduced by 17% in Pacific Rose TM apple trees when subjected to partial root zone drying as compared with commercially irrigated control Leaf area The leaf growth has been reported to be quite sensitive to water stress (Hsiao, 1973; Begg and Turner, 1976). In grapes, the leaf area was reduced when the soil moisture was less than 70 per cent of field capacity as compared to those above 70 per cent of field capacity (Magriso, 1979). However, the expansion growth of leaves in peach trees is only slightly sensitive to water stress (Li et al., 1989). A rapid increase in leaf area was obtained in Hayward kiwifruit vines when irrigated daily using drip system after bud burst in comparison to nonirrigated vines (Xiloyannins et al., 1990). Chartzoulakis et al. (1993) recorded 72 and 77 per cent reduction in leaf area of young kiwifruit vines of cv. Hayward under 60 and 40 per cent of field capacity, respectively in comparison to the vines irrigated at 100 per cent field capacity. Poni et al. (1993) observed that in potted Pinot Noir grapevines, the total leaf area on vines stressed before veraison did not statistically differ from well watered plants. Cuevas et al. (2000) observed that leaf area get decreased in severely stressed grape vines. Mills et al. (1994) observed that in Braeburn apple raised on MM.106 rootstock, the leaf areas (m 2 ± SE) for 10 irrigated and 11 non-irrigated trees were 9.1 ± 2.4 and 8.6 ± 2.3, respectively. In peach cultivar Golden Queen, the deficit irrigation reduced leaf size to cm 2 from cm 2 at full irrigation (Boland et al., 2000). Romero et al. (2010) observed that in red wine grapevine cultivar Monastrell grafted onto 1103 Paulsen rootstock, the total leaf area per vine at 36

57 veraison was significantly higher in the control than in RDI-1 and RDI-2. These differences were mainly due to differences in the main shoot leaf area, since lateral leaf area between treatments was similar. From June to early August, the leaf area of the main shoots was reduced by 14% and 19% in RDI-1 and RDI-2, respectively, compared with only 2% in control vines. The lateral leaf area was reduced between 3% and 5% in the RDI treatments. During post veraison, the main leaf area was reduced by 38% and 51% in RDI-1 and RDI-2, respectively, compared to only 19% in control vines. The lateral leaf area was reduced by 26% in RDI-1 and 38% in RDI-2 compared with only 13% in control. After veraison, the reduction in leaf area during ripening was due to intense leaf abscission and leaf senescence in RDI vines Leaf thickness and leaf yellowing In an experiment on anatomical adaptations in vegetative structures of apricot tree cv. Amor El Euch grown under water stress, the adaptation of Amor El Euch cultivar to water stress was attributed to thickening of leaves (Laajimi et al., 2011). In Himachal Pradesh, olive trees exhibited leaf yellowing symptoms under water stress conditions (Singh and Sharma, 2010) FLOWERING AND FRUITING Bloom intensity The moderate postharvest water deficits lead to an increase in bloom density in the next year in peaches and pears (Mitchell et al., 1984; Larson et al., 1988; Li et al., 1989). Positive effects of deficit irrigation on bloom density have also been reported in subtropical fruits (Nakajima et al., 1993; Sanchez-Blanco et al.,1989) including different citrus crops (Raese et al., 1982; Mitchell et al., 1984; Chalmers et al., 1985). However, others have documented either no effects or lower bloom density when deficit irrigation was implemented in Braburn apple (Mills et al.,1994), Anjou pear (Brun et al., 1985) and Hosui Asian pears (Caspari et al., 1994). Brun et al. (1985) also reported no effect or lower bloom density in Anjou pears trees when deficit irrigation was given. In loquat cutivar Algerie, the deficit irrigation did not affect the number of flowers per panicle, but a higher proportion of secondary shoots formed the flowers under 37

58 RDI, thus resulting in greater bloom density. In Braeburn apple, there was lower bloom density when deficit irrigation was implemented (Mills et al., 1994). However, the levels of return bloom showed no significant difference in the number of flower clusters recorded between treatments of irrigated and not irrigated at S1(167 DAFB) and S2 (180 DAFB) stages of harvesting. In three-year-old Kyoho grapes, severe water stress given by cutting off the irrigation for 16 days induced early bud break, enhanced flowering and increased cluster size, fruit set and fruit growth (Ndung et al., 1996). However, mild water stress (10 days) was found to be less effective. Regulated deficit irrigation has been shown to change flowering behavior the following year of its application, both in Prunus (Girona et al., 1997; Goldhamer and Viveros, 2000; Johnson et al., 1992; Lampinen et al., 1995; Li et al., 1989) and in Pyrus (Caspari et al., 1994; Marsal et al., 2002). Girona et al. (2003) observed that flower density and fruit set were significantly reduced by the postharvest deficit treatments (RDI-SII-P and RDI-P) given to peach cultivar Sudanell. Water stress usually triggers flower formation and induced flowering in citrus and therefore increased the number of fruits per tree (Davenport 1990; Goldschmidt and Samach, 2004). Cuevas et al. (2007) reported that deficit irrigation treatments in grapes promoted earlier flowering when compared with control vines and the more deficit conditions allowed desirable intensity of bloom. Further, dry weight of flowers remained negatively affected by water stress, although no impact was translated on initial fruit set Fruit set and fruit retention Kiwifruit cultivar Hayward showed variation in the percentage of reproductive buds and in the number of fruits per fruitful shoot (Testolin, 1990), which could be due to competition or inhibition among the buds as hypothesized by Grant and Ryugo (1982). However, irrigation regimes did not significantly affect the fruit set in kiwifruit cv. Allison (Rana, 1998). In citrus, water stress applied during flowering, fruit set and initial period of fruit growth reduced the number of fruits because of increased fruit drop (Kriedemann and Barrs, 1981; 38

59 Doorenbos and Kassam, 1986; Ginestar and Castel, 1996). The percentage of fruit fall has also been correlated with the severity of water stress in lemon trees (Barbera and Carimi, 1988; Gonzalez- Altozano, 1998). Talaie et al. (2000) observed that the water stress applied at first stage of fruit growth (WS1) resulted in reduction in fruit set in peach cultivars, White Mashhad, Red and White Mashhad, Red Haven and J. H. Hale. However, no significant differences were found for flowering density among these cultivars. In Anna apple, fruit set was significantly reduced with deficit irrigation while, the excessive irrigation and normal irrigation had no significant effects fruit set (El- Sabagh and Aggag, 2003). Korkutal et al. (2011) observed that the berry set ratio, phonologic stages and berry development were negatively affected by early water stress conditions in grape cultivar Merlot grafted on SO4 rootstocks. Rapoport et al. (2011) observed that the water deficit during inflorescence development in olive cv. Picual reduced many different flowering parameters including inflorescence number, flower number, imperfect flower number and percentage and ovule development, whereas prior to abscission of bloom it produced mild or no effects. However, when water deficit occurred during flowering and initial fruit set, the petals of many flowers dried closed and abscised as a unit, exposing a senescent stigma which was no longer receptive to pollination. In this study, fruit production closely followed flowering parameters as lower fruit number was recorded either when flower number was reduced or fertilization inhibited Fruit yield The variations in the percentage of reproductive buds and in the number of fruits per fruitful shoot in kiwifruit vine could be due to competition or inhibition among the buds, as suggested by Grant and Ryugo (1982). Under optimum water conditions, a kiwifruit plant produces a large amount of carbohydrates, thereby enhancing root and canopy development, substantial and high-quality fruit, and photosynthesis storage (Sale, 1985). Total yield of quality fruits is an important factor in commercial fruit growing. The increase in yield as a result of irrigation has been reported in kiwifruit by various workers (Prendergast et al., 1987 ; Judd et al., 1989). 39

60 Howatson (1989) recorded better yield in kiwifruit when irrigated 1.5 times of the calculated plant water requirement. Xiloyannis et al. (1990) obtained 10 kg more fruits per vine which received m 3 /ha water more during the irrigation season. The higher yield was not due to larger fruit size but due to a higher number of fruits per vine which probably resulted from better fruit set or greater vegetative growth resulting in production of more buds. Similar increase in yield with frequent irrigation was reported by Blanchet (1990) and Mc Aneney et al. (1992) in kiwifruit. Magliulo et al. (1991) obtained higher yield in kiwifruit when vines were irrigated at 12 per cent ET than at 50 per cent ET. Cordia et al. (1993) recorded maximum yield (9.44 Kg/vine) when irrigation was given at 100 per cent Etc and minimum (4.72 kg/vine) in non -irrigated kiwifruit vine of cv. Hayward. The water stress reduces berry size and yield (Matthews et al., 1987; Matthews and Anderson 1988, 1989; Hamman and Dami, 2000; Salon et al., 2005) in kiwifruit. Water stress reduced fruit yield and/ or biomass production in peach (Tan and Buttery, 1982) and strawberry (Kirnak et al., 2001). Regulated deficit irrigation was shown to conserve water in vineyards without adversely affecting yield (Stikic et al., 2003; Kang and Zhang, 2004; Fuentes, 2006). Chaves et al. (2007) also reported that the reductions in the amount and timing of supplementary irrigation under deficit irrigation may save water without reducing the amount or quality of the harvested yield in grapes. Shellie (2006) however, observed that the yield of grape cv. Merlot was reduced up to 48% under deficit irrigation. The reduction in yield was associated with smaller berries, lower cluster weight, and fewer clusters per vine. Bryla et al. (2009) studied the effects of irrigation method and level of water application on yield and fruit quality in highbush blueberry ( Vaccinium corymbosum L.) cv. Elliott and observed significantly higher berry yield in plants irrigated at 100% ETc than those irrigated at 50% Etc, however the yield was similar in plants irrigated at 100% and 150% Etc SOIL MOISTURE Kiwifruit plant has a small range of soil-water absorption (Valenzuela, 1988). Xiloyannis et al. (1990) have recommended maintaining soil water content of less than 50% whereas, Ferreyra et al. (1988) have suggested less than 40

61 20% of total soil-water retention. Miranda and Gurovich (1988) have determined that it is possible to utilize up to 75% of the available soil water without having a deleterious impact on plant development and fruit production. Kiwifruit requires very frequent irrigation to sustain an adequate plant water status because of its low stomatal regulation (Beutel, 1985; Kulczewski, 1988). Water requirements in this species are affected by climate and soil characteristics as well as by plant morphology and physiology. Kiwifruit is also considered a water profligate species (Buwalda and Smith, 1990). Its roots clearly have the potential to transport much higher rates of water than normally occurs when the entire root zone is supplied with water (Green et al.,1995). Green and Clothier (1995) observed that water absorption was enhanced 10-fold upon re-watering in the roots of kiwifruit vines that had been previously water deprived. Gucci et al. (1996) observed that during a drought cycle in Hayward cultivar of kiwifruit, soil moisture content would typically decrease from 25-34% (soil capacity) to 11% (wilting point) in 5-9 days for vines grown in containers and from 22 to 16 % in 16 days for those growing in the field. Miller et al. (1998) reported that following withholding of irrigation, there was a steady decline in soil moisture levels around the roots of kiwifruit cultivar Hayward vines and after 6 days, the volumetric water content of soil in the non-irrigated tubs had been reduced by 60%, and applications of 1.5 1itre of water per vine every second day was then necessary to maintain a moderate water stress. Over the 21 days experimental period, soil moisture levels of 15-20% were maintained around the roots of the stressed vines. Boselli et al. (1998) reported that in Cabernet Sauvignon Grapevine there were large differences in soil moisture content from the 20 th DAFB, between the two years. During 1993, the moisture content gradually decreased, falling from approximately 25 per cent at flowering to 14 per cent at ripening. By contrast during 1994, the soil moisture content remained constant, peaking at 53 days from full bloom when rainfall occurred and was always greater than 20 per cent. 41

62 Soil depth and soil water holding capacity have been reported as interacting factors in the success of regulated deficit irrigation (Behboudian and Mills, 1997). In an experiment on trees of apricot cv. Bulida on Pollizo prune rootstocks, growing under field conditions in 35 liter pots, Ruiz-Sanchez et al. (2000) applied six different irrigation treatments viz. T O (fully irrigated control), T 1 and T 2 - drip irrigated daily to field capacity and 50% FC respectively, T 3 - drip irrigated at 25% of control treatment and T 4 and T 5 irrigated at every 3 and 6 days of FC, respectively and observed that during the pre-conditioning period, a substantial depletion in soil water occurred in treatments T 3 (irrigated at 25% of control) and T 5 (irrigated every 6 days). The values of soil water content were slightly higher in pots from the T 2 treatment (irrigated at 50% of control) than those of the T 4 treatment (irrigated every 3 days). Centeno et al. (2010) studied the relationship between soil and plant water status in wine grapes cv. Tempranillo under various water deficit regimes involving irrigation replenishing 45% (T 1 ) and 30% (T 2 ) of the reference evapotranspiration and the non-irrigated treatment (T 3 ) and placed the soil moisture sensors at 3 different depths i.e. 0.3 m (Ψ 0.3 ), 0.6 m (Ψ 0.6 ) and 1.2 m (Ψ 1.2 ) and observed that sensors placed at 0.3 m depth quickly responded to irrigation by increasing Ψ 0.3 levels and those placed at the 0.6 m depth Ψ 0.6 progressively decreased showing significant differences with T 1 and rest of treatments, while no significant differences were found in the treatment of Ψ 1.2. More recently, Romero et al.(2012), in an experiment on grape vines cv. Monastrell (syn. Mourvedre) grafted on 1103 Paulsen rootstock, the same irrigation volume was applied to the entire (DI) or part of the root zone (PRD) under five deficit irrigation treatments: DI-1, PRD-1, DI-2, PRD-2 and control [plants irrigated at 60% Etc (crop evapotranspiration) for the whole season (308mm year -1 )]; and wherein, DI-1 and PRD-1 received the same irrigation as controls before fruit set, 30% Etc from fruit set to harvest and 45% Etc postharvest (192 mm year -1 ) and DI-2 and PRD-2 were same except 15% Etc was applied from fruit set to harvest (142mm year -1 ) it was observed that the PRD-1 vines extracted more water from deeper soil layers during soil drying. 42

63 CANOPY TEMPERATURE The sensitivity of kiwifruit to leaf temperature and the consequent reduction in photosynthesis has important implications for their field management (Chartzoulakis et al., 1993). However, irrigation water could cool the canopy and thus avoid leaf heating and potentially leaf damage, including necrosis. Further, some limitation to photosynthetic rate (Pn) occurr ed at leaf temperatures above 25 o C in A. deliciosa. Gucci et al. (1997) estimated that under moderate water stress, kiwifruit vines may have leaf temperatures of C higher than well-watered vines and this difference could be 5 to 6 0 C under severe water stress. Ruiz-Sanchez et al. (2000) imposed the water stress upon young apricot cv. Bulida plants and observed that the canopy temperature of the plants which was around 31 ºC in control, increased to around 35 ºC under T-3 (irrigated at 25 % of control treatment ) and T-5 (irrigated at every 6 days of FC ). The remaining stress treatments (T-1, drip irrigated daily; T-2 irrigated daily at 50% of T-0; T-4 irrigated to field capacity every 3 days) also increased canopy temperature significantly with the mean values 3 o C above the air temperature, in this study. Further, canopy minus air temperature (Tc -Ta) values showed that the well irrigated plants (T-1 treatment) kept their leaves 3ºC lower than air temperature, indicating the cooling effect of adequate transpiration levels ANATOMICAL AND PHYSIOLOGICAL CHARACTERISTICS AND WATER RELATIONS Stomatal studies Stomatal size Stomatal size was defined as the length in micrometres between the junctions of the guard cells at each end of the stoma, and may indicate the maximum potential opening of the stomatal pore, but not the aperture of opening that actually occurs (Malone et al., 1993; Maherali et al., 2002). In A. deliciosa, stomatal closure was observed significantly more with the decreases in midday leaf water potential (Chartzoulakis et al., 1997 ; Gucci et al.,1993). 43

64 Stomatal density In low bush blueberries ( Vaccinium angustifolium Ait.), the stomatal density declined under drought treatment in both vegetative (sprout) and crop years compared to irrigated plants (Glass et al., 2005). The stomatal density of kiwifruit leaves ranges from 100 to 160 mm -2 according to leaf expansion (Nuzzo et al., 1990). However, stomatal density in Actinidia is lower than in Vitis, where it is largely over 200 stomata mm -2 (During, 1980). Stomatal densities and sizes are frequently used to estimate stomatal resistance (Ti cha, 1982). Stomatal density as well as length and width of stomatal pore decreased with the increasing moisture tension and these responses might have been mediated through abscisic acid produced within the leaf that transported to stomata (Addicott, 1983) Leaf water potential The leaf water potential before sunrise a useful indicator of available water in the soil for grapevine, almond and plum trees (Dettori, 1985; Natali et al., 1985). Leaves of kiwifruit become severely wilted when the leaf water potential falls below -0.9 MPa, but stomata do not close fully even where the leaf water potential is as low as -2.9 MPa (Dick, 1987). Xiloyannis et al. (1988) observed that leaf water potential varied among three different fruit crops namely peach, olive and kiwifruit with a drop in soil water content. In peach cultivars Armking and Red Top trees, a drop in soil water content from 100 to 30% of available water provoked a drop in leaf water potential of approximately 0.3 MPa and in olive cv. Leccino trees, the rapid drop in leaf water potential occurred when water content in the soil was around 20% of available water, however, in kiwifruit cv. Hayward plants, drop in leaf water potential occurred at soil water content levels of approximately 45-50% of available water. Zhang and Archbold (1993) reported that the water stress conditions resulted in reduction in leaf water potential which increased the solute concentration in leaves of Fragaria chiloensis BSP14. Mills et al. (1994) reported that the non-irrigated Braeburn apple trees developed reduced water potential and stomatal conductance and the fruit from these trees showed earlier 44

65 sugar accumulation during the season. Such fruit also had reduced Ca 2+ concentration than that of irrigated. Okamoto et al. (2004) observed that in Chardonnay cultivar of grapevine, both the early and late water stress treatments resulted in significant reduction in leaf water potential. In grape cv. Merlot, the pre and post-veraison leaf water potential responded to differential irrigation and ranged seasonally from to (Shellie, 2006) Stomatal resistance Smart (1974) demonstrated large decreases in transpiration rate, hence higher stomatal resistance, and leaf water potential of water-stressed field-grown Shiraz grapevines. Stomatal resistance is known to increase significantly when vines experience severe water stress (Smart and Coombe, 1983). Grimes and Williams (1990) however, observed yield reductions in drought -stressed Thompson Seedless vines with increased stomatal resistance. Stomatal closure in plants is an adaptation mechanism to water deficit, which causes water saving and protect plants against drought stress (Moriana et al., 2002). Saei et al. (2006) observed that drought stress had a significant effect on stomatal behavior of leaves of olive cv. Zard and caused an increase in stomatal resistance and closed them. Sena et al. (2007) observed variation in stomatal resistance of perennial tropical crops under dry and rainy season. During the dry season, there was a decrease in values of stomatal resistance in the following order: coffee> cashew> guava> rubber, with the values from 2.5 to 30.0 s cm -1. During the rainy season, the stomatal resistance values however, varied from 1.5 to 30 s cm -1. During the rainy season, the rubber tree continued to present lower stomatal resistance and consequently higher transpiration. Stomata also sense the water status of distant tissues such as roots via the long distance transport of ABA in the xylem. It is therefore believed now that stomatal activity is regulated by both hydraulic and chemical ABA signals (Christmann et al., 2007; Schachtman and Goodger, 2008). 45

66 Transpiration rate The studies conducted on Cabernet Sauvignon Grapevine by Boselli et al. (1998) revealed that the transpiration per unit of surface area (mmol H 2 O m -2 s - 1 ) was always higher in leaves than in berries. The leaf transpiration varied from 5.62 mmol H 2 O m -2 s -1 to 2.92 mmol H 2 O m -2 s -1 in 1993 in the period between the 8 th and 86 th day after full bloom (DAFB), and from 6.49 mmol H 2 O m -2 s -1 to 4.37 mmol H 2 O m -2 s -1 in 1994 between the 12 th and 94 th DAFB. Escalona et al. (2000) observed in grapevine cv. Tempranillo, the transpiration rates were very low in water stressed plants (around 15 g h -1 m -2 ) in comparison to the irrigated ones (around 250 g h -1 m -2 ) for the same hours. The drought tolerant characteristics of some strawberry cultivars such as osmotic adjustment, small leaf area and low transpiration rate are benefit for cultivar selection that has tolerance to drought (Grant et al., 2010) Photosynthetic rate Correia et al. (1990) suggested that the midday decline in photosynthesis in grapevine resulted from a direct inhibitory effect of high light at the chloroplast level. In kiwifruit, water stress reduced photosynthesis without reducing internal CO 2 suggesting that stress was acting by directly inhibiting biochemical processes (Chartzoulakis et al., 1993). Peng and Zhang (1995) observed adverse effect of relative humidity at less than 60 or more than 80 per cent soil on photosynthesis in kiwifruit vines. A decline in the photosynthetic rate under water stress conditions could be attributed either to a decrease in stomatal conductance or non-stomatal limitations (Jones, 1992; Cornic and Massacci, 1996). Patakas et al. (2005) observed that in grape cv. Malagouzia the photosynthetic rate was significantly lower in stressed treatments than in well- watered treatment. Bertamini et al. (2006) observed significant reduction in photosynthetic rate in grapevine cultivar Riesling when the vines were subjected to water deficit. Song et al. (2007) suggested that the moderate water stress leads to decrease in photosynthetic rate by affecting stomatal conductance in litchi. 46

67 Chlorophyll content Ramteke et al. (2001) observed, the chlorophyll content was decreased significantly by per cent under water stress condition in grape cv. Tas-A- Ganesh grafted on Dogridge rootstock. Likewise, the chlorophyll content significantly decreased when the vines of another grape cv. Riesling were imposed to water stress treatment (Bertamini et al., 2006). Hussein (2008) observed reduction in chlorophyll content in olive cultivar Manzanillo under lower irrigation regime compared to those under the higher irrigation regime. The severe water stress reduced the chlorophyll content in Monastrell grapevines grafted onto 1103 Paulsen rootstocks (Romero et al., 2010) Proline content Proline is accumulated in many plant species under various stress conditions (Delauney and Verma, 1993), but it has not been always linked to osmotic adjustment and can exert a possible toxic role in the inhibition of malate dehydrogenase and nitrate reductase activities (Nikoloupoulos and Manetas, 1991). Proline accumulation in ber increased a 35 fold in leaves during drought conditions (Clifford et al., 1998). The proline content was higher water stressed vines in comparison to non-stressed vines of grape cv. Tas-A-Ganesh grafted on Dogridge rootstocks (Ramteke et al., 2001). An increased proline level is another common response of plants to osmotic stress (Karabal et al., 2003). Sofo et al. (2004) observed increase in proline content in olive trees when subjected to drought stress conditions, indicating a possible role of proline in drought tolerance. In grapevine cv. Riesling, a significant two- fold increase in proline content was recorded when these vines were subjected to water stress treatment (Bertamini et al., 2006). In pears, the proline content increased with the soil water stress (Sharma and Sharma, 2008a; Wang et al., 2008). Accumulation of proline permits osmotic adjustment, which is considered to be involved both in dehydration avoidance and in tolerance mechanisms (Blum, 2005; Trovato et al., 2008). 47

68 Free amino acids Drought stress resulted in accumulation of free amino acids derived from protein hydrolysis or from an inhibition of protein synthesis in maize plants (Navari- Izzo et al., 1990). In Actinidia deliciosa vines, an increase in proline as well as in other amino acids were noticed following water deficit, however their contribution to osmotic potential was negligible. In an experiment on two-yearold kiwifruit cv. Hayward vines obtained by micropropagation and from cutting to three days of water stress, it was found that the Actinidia deliciosa may primarily respond to water deficit by altering the rates of amino acid metabolism by making the quantitative and qualitative changes in free amino acids (Milone et al., 1999). Bertamini et al. (2006) observed that the grapevine cv. Riesling when subjected to water deficit resulted in the increase in the accumulation of free amino acids Relative water content Leaf relative water content reflects the water content in plant tissue and is often used as a parameter to assess the severity of water stress. Gucci et al. (1993) observed that leaf RWC of irrigated kiwifruit cv. Hayward vines typically ranged from 97.7% to 99.5% and from 95% to 97.5% at predawn and midday, respectively and RWC of stressed kiwifruit vines ranged from 96.5% to 98.5% and from 90% to 93.5% at predawn and midday, respectively. Miller et al. (1998) performed a two year experiment in New Zealand to determine the responses of kiwifruit ( Actinidia deliciosa cv. Hayward) to water stress conditions in which plants were subjected to a stress regime composed of three different treatments: Control (water received according to culture demands), water stress in early summer and water stress in late summer and observed that there was little effect on water content of leaves on stressed vines. Water content gradually declined over the season from 73% just after bud break, to 68% at harvest. Bertamini et al. (2006) observed that the water deficit significantly decreased the relative water content in grapevine cv. Riesling. Wang et al. (2008) observed the relative leaf water content in pear cv. Cuiguan decreased with the 48

69 soil water stress. The plant growth indices and leaf relative water content were significantly reduced under drought stress in different almond genotypes (Karimi et al., 2012) Xylem development Xylem vessels serve as a major conduit for the delivery of inorganic ions and certain organic compounds to plant tissues. In kiwifruit vines, xylem fluid is extremely dilute (i.e.,>95% water) and consists primarily of amino acids, organic acids and inorganic ions (Andersen and Brodbeck, 1989a-b; Andersen et al., 1989, 1992) Development of primary xylem vessels Lovisolo et al. (2000) observed that when Vitis vinifera cv. Freisa vines were subjected to water stress for 40 days there was decrease in size of xylem vessels and this reduction was linked with limited hydraulic regulation and transpiration flow. They further noted that in grapevine the regulation of xylem development may contribute to drought resistance. Sharma and Sharma (2009) observed that the xylem vessel density and diameter of xylem vessels were not significantly influenced by drought stress treatment in Flemish Beauty pear. In mango cv. Chokanan, the water stress resulted in development of compact cells due to thickening of epidermis, cortex, sclerenchyma, increase in phloem and xylem thickness, sclerenchyma area, pith area and diameter (Zaharah and Razi, 2009) Development of secondary xylem vessels The hydraulic system of kiwifruit is typical of other lianoid species, with low axial xylem resistance, high whole plant hydraulic conductance and high rates of transpiration in comparison with tree species such as olive (McAneney and Judd 1983, Dichio et al., 1999). Low axial resistance is achieved by semiring porous wood with xylem vessels averaging mm in length and up to 0.5 mm in diameter, connected by simple perforation plates (Condon, 1992). 49

70 Endogenous hormones Cytokinin content Dry et al. (2001) observed that the shoot growth inhibition in PRD grapevines paralleled with a marked decrease in the concentration of CK in shoots and roots. In apple cv. Red Fuji grafted on Malus micromalus, the cytokinin content declined more in the later stage of drought stress than the early drought stage (Li et al., 2003). Gao et al., (2004) observed that the supply of zeatin decreased under drought stress in pear Abscisic acid In a study on drought tolerance in Fuji apples, Yoon (1995) proposed that the reduction in available water results in the production of chemical signals such as abscisic acid that in turn may regulate the stomatal behaviour. Atkinson et al. (1998) observed that water stress induced increases in ABA level was closely related with changes in leaf turgor potential in Malus pumila. Peterlunger et al. (2000) observed that the ABA concentration increased two fold under water stress in the leaves and roots of Vitis vinefera cv. Muller Thurgau, whereas, the xylem sap ABA underwent even a much bigger increase of about eight time. Stomata closing of strawberry plants when exposed to drought can be mediated by rapid increase in abscisic acid (ABA) synthesis in the root and ABA delivery from the roots in the transpiration stream (Blanke and Cooke, 2004). Calcium protein kinases and phosphatases, and membrane trafficking components have been shown to play a role in ABA signaling of guard cell movement, as well as ABA- independent regulation of ion channels by osmotic stress (Luan, 2002). Li et al. (2003) observed that drought stress treatments to the plants of apple cv. Red Fuji grafted on Malus micromalus resulted in an increase in the concentration of ABA in comparison to control and the endogenous ABA originated mainly from the roots in earlier drought stage and from the leaves in the later drought stage. Gao et al. (2004) reported that pear plants subjected to water stress had significantly higher concentrations of abscisic acid in their leaves in comparison to unstressed plants. In pear cv. Cuiguan, the abscisic acid content increased with the soil water stress (Wang et al., 2008). 50

71 Leaf nutrient status Water deficit decreased plant growth, fruit yield and quality as a result of reduction in transpiration and inhibition of uptake of nutrients (Kirnak et al., 2001). Rana (1998) found higher leaf nutrient content in the vines of kiwifruit cv. Allison when subjected under higher soil moisture than those irrigated with less quantity of water. Hussein (2008) in a study on the response of Manzanillo Olive (Olea europaea L.) cultivar to different irrigation regimes and potassium fertigation under Tabouk conditions, Saudi Arabia observed that deficit irrigation decreased the leaf N P K and Ca contents without affecting Mg content Nitrogen Regulated deficit irrigation increased leaf N content in peach (Williamson and Coston, 1990). In Cabernet Sauvignon Grapevine, the leaf mineral N composition was not affected by the variation on soil moisture, whereas the berry N contents were positively correlated with soil water content (Boselli et al., 1998). The severe water stress condition decreased the leaf N content in Monastrell red wine grapevines grafted onto 1103 Paulsen rootstock (Romero et al., 2010). Deficit irrigation treatments applied during different phonological stages from harvest to inflorescence emergence to the trees of Manzanillo olive cultivar in the private orchard located in the dessert of Cairo significantly decreased leaf total nitrogen in descending order for those irrigated at 66% ETc and 33% ETc. in comparison to those irrigated at 100% Etc. (Mehanna et al., 2012) Phosphorus In Cabernet Sauvignon Grapevine, water stress did not influence the leaf P contents, whereas, the berry P contents were positively correlated with soil water content (Boselli et al., 1998). In strawberry, the concentration of P decreased by water stress (Kirnak et al., 2001). Mehanna et al. (2012) observed that trees of olive cv. Manzanillo irrigated with 100% Etc through all season (control) recorded the highest significant values of leaf P contents, followed in the descending order by those irrigated with 66% Etc and 33% Etc, respectively. 51

72 However, there were no significant differences in leaf P contents of trees given DI treatments at different stages of experiment Potassium Boselli et al. (1998) reported that the leaf K composition of Cabernet Sauvignon Grapevine was affected by the variation on soil moisture, whereas its berry K contents were positively correlated with soil water content. Boland et al. (2000) found that deficit irrigation reduced the K content of peach leaf. In strawberry, the concentrations of K decreased significantly by water stress (Kirnak et al., 2001). The concentration of K + in leaves decreased significantly with water stress in pear (Sharma and Sharma, 2008 a). The potassium content decreased significantly in leaves of olive cv. Manzanillo with the increasing severity of drought stress (Mehanna et al., 2012). In this study, the leaf potassium content was 0.83 and 0.95% in the year 2009 and 2010, respectively at full irrigation and it got reduced to 0.66 and 0.86% with irrigation at 33% Etc from pit hardening to harvest Calcium The leaf and berry Ca content appeared to be greater with high soil moisture in Cabernet Sauvignon Grapevine (Boselli et al., 1998). Porro et al. (2010) observed low Ca levels in leaves of grapevine cv. Lambrusco when subjected to water stressed treatment Magnesium Hussein (2008) observed no influence of deficit irrigation on leaf Mg content of Olive ( Olea europaea L.) cultivar Manzanillo grown under Tabouk conditions, in Saudi Arabia. Porro et al. (2010) observed reduction in magnesium levels in leaves of grapevine cv. Lambrusco when subjected to water stressed treatment PHYSICO-CHEMICAL CHARACTERISTICS OF FRUITS The method of irrigation and the amount of water applied have a marked effect on fruit yield and quality (Holzapfel et al., 1985). The RDI benefits were primarily focused on the reduction of vegetative growth and enhancement of fruit 52

73 growth (Chalmers et al., 1981; Li et al., 1989), other advantages have also been described, i.e., a general tendency to improve fruit taste and quality (Fereres and Goldhamer, 1990), and an improvement of postharvest shelf life (Crisosto et al., 1994). Miller et al. (1998) observed a significant loss in fruit weight, especially in plants exposed to stress in early summer (fruit set period) in kiwifruit cv. Hayward. They also observed that water stress later in the season, at the start of the second phase of fruit growth, accelerated ripening processes so that the stressed fruit matured earlier than the controls. Zegbe and Behboudian (2008) reported that in Pacific Rose TM, apple partial root zone drying did not adversely affect yield and fruit quality, but improved the water use efficiency by 120%, saving 0.14 mega liters of water per hectare. Sotiropoulos et al. (2010) observed that in clingstone peach cv. A-37, the regulated deficit irrigation at second phase of fruit growth resulted in increased soluble solids content of the fruits in comparison to control. However, it did not affect the fruit acidity and fruit firmness Fruit size and weight The growth behavior of fruit based on water availability has important practical implications for irrigation management. It implies that even modest periods of water stress can have pronounced effects on final fruit size (Prendergast et al., 1987). Brown and Brown (1987) found a difference of 16 g between kiwifruit fruits of irrigated and non-irrigated blocks in Poverty Bay where usually orchards were not irrigated. Miller et al. (1998) observed that harvest weight of fruit from early- stressed vines was approximately 25% less than the weight of fruit on control vines in kiwifruit. In field-grown and potted Cabernet Franc grape, the early irrigation deficits were effective in reducing berry weight (Hardie and Considine, 1976; Matthews and Anderson, 1989; Matthews et al., 1987). The reduction in harvest weight is particularly severe if vines were subjected to drought stress early in the growing season when fruit are in their most rapid phase of expansion (Prendergast et al.,1987). In grape vine, water stress is thought to enhance fruit quality for wine production (Jackson and Lombard, 1993), but may at the same time impact vineyard profitability by reducing berry size and lowering yield. 53

74 Tuccio et al. (2012) practiced two different water regimes i.e. water stress (not irrigated) and moderate water deficit (partially irrigated) in the vineyard of grape cv. Aleatico and observed 20 per cent reduction in berry weight in water stressed plants in comparison to those subjected to moderate water deficit treatment Fruit firmness A mild drought stress during early fruit growth can result in beneficial effects on post-harvest storage characteristics of the fruit as fruit from nonirrigated vines were firmer and stored better than fruit from irrigated vines of kiwifruit cv. Hayward (Reid et al., 1996). Bernstein and Lustig (1981) stated that in Dattier grapes, water loss from berries to the atmosphere or to the plant results in a decrease of turgor pressure and consequently, of firmness. In a study on the response of five-year-old Braeburn apple trees to reduced plant water status, the fruit firmness was significantly decreased in water stressed fruits when harvested at 167 DAFB but, not in those harvested 180 DAFB (Mi lls et al., 1994). Mpelasoka et al. (2001) found that deficit irrigation increased total soluble solids and fruit flesh firmness in Braeburn apple. Porro et al. (2010) observed that the water stress decreased the firmness of berries and increased the berry skin thickness in grapevine cv. Lambrusco Total soluble solids Matthews and Anderson (1988) found higher soluble solid content, ph, and anthocyanins in the berries of field-grown grape cv. Cabernet Franc following early water deficits. In peach, ABA content and total soluble solid content (TSS) increased under conditions of water stress (Kobashi et al., 1997). The fruits contained higher ABA content when the soil potential was below M Pa, which coincided with that recommended for peach trees during fruit maturation. The higher ABA content enhanced assimilates partitioning into fruits resulting in higher TSS. An increase in TSS in response to regulated deficit irrigation could be due to a dehydration effect (Gonzalez- Altozano, 1998) or to active osmotic adjustment in fruit (Huang et al.,2000; Barry et al., 2004). Miller et al. (1998) observed an increase in the total soluble solids in fruits of kiwifruit cv. Hayward due to water stress. Similar increases in concentrations of total 54

75 soluble solids at harvest have also been measured in drought stressed Braeburn apples (Mills et al., 1994) Titratable acidity In Braeburn apple, fruits from non-irrigated trees had higher titratable acidity than those from irrigated trees at 167 DAFB and 180 DAFB (Mills et al., 1994). In grape, a reduction in titratable acidity associated with water deficits has been attributed to reduction in malate (Matthew and Anderson, 1988; Esteban et al., 1999). Peterlunger et al. (2002) observed that water stress reduced the titratable acidity at harvest in Merlot grape vines grafted on SO4 rootstock. However in Perlette grape, the titratable acidity of berry was not affected by irrigation (Phadung et al., 2005). The application of irrigation at 50% of Etc to plants of blueberry cv. Elliott decreased the titratable acidity in comparison to irrigation treatments applied at 100 and 150% of Etc (Bryla et al., 2009) Sugar content In Merlot grape grafted onto SO 4 rootstocks, increased sugar levels was observed at fruit maturity in R18 clone under water stressed treatment compared to the control (Peterlunger et al., 2005). Wang et al. (2008) observed an increase in soluble sugar content with the increase in soil water stress in pear cv. Cuiguan. Intrigliolo et al. (2012) observed that the Vitis vinifera cv. Tempranillo vines when exposed to water deficit at early (pre -veraison) stage accumulated more sugar in comparison to those exposed to late season water deficit treatment Ascorbic acid Buendia et al. (2008) observed that regulated deficit irrigation strategies resulted in reduction of vitamin C content in peach cv. Flordastar. In Flemish Beauty pear, the drought stress treatment decreased the leaf ascorbic acid content when compared with control (Sharma and Sharma, 2008c; Sharma and Sharma, 2009). 55

76 2.2.2 EFFECT OF MULCHING The relevant available information on the effects of in situ moisture conservation on different aspects of present study on kiwifruit has been reviewed under appropriate heads. The practice of in situ moisture conservation involving the use mulch materials has been recognized universally as potential agent of moisture conservation during dry spell in comparison to clean cultivation in many fruits (Stojanowska, 1987; Luckhov et al., 1989; Raina, 1991) VEGETATIVE GROWTH Shoot growth Beatli (1955) recorded vigorous vine growth in grapes under straw mulch. Moore (1963) also reported increased vine growth in Concord grapes when black polythene mulch was applied at the time of planting and maintained during the first summer. In Coahuila, Mexico, the grapevines cv. Barbera grafted on A X RC rootstocks were grown with or without black plastic mulch during and it was observed that mulching significantly increased the shoot formation only in the first 3 years (Ibarra et al., 1996). Heiberg (1996) observed the increase in the length of internodes as a result of application of black polyethylene mulch in red raspberry cultivars Chilliwack and Veten. In Merlot cv. of grape, the bud break and vegetative growth were not affected significantly by the polyethylene mulch (Bowen et al., 2004) Leaf area In strawberry cv. Oso Grande, different type of mulch material and irrigation viz., bare soil + water stressed (WS); bare soil + uns tressed (control); black polyethylene mulch + water stress and wheat straw mulch + water stress were applied and it was observed that the leaf area index was improved with the black polyethylene mulch + water stress; and wheat straw mulch + water stress in comparison to bare soil + water stressed (WS); bare soil + unstressed control (Kirnak et al., 2001). Phadung et al. (2005) observed that the leaf size was not affected by irrigation and mulches in Perlette grape. 56

77 FLOWERING AND FRUITING Bloom intensity In strawberry cv. Chandler, black polythene mulch under micro irrigation system resulted in early flowering and high yields of superior quality fruits (Singh et al., 2005). Mulching increased the quantity of flower buds and leaves but, delayed flowering time by 3-5 days in sweet cherry cv. Hongdeng ( Wang, 2005). In strawberry cv. Sweet Charlie, the number of flowers per plant were greatly higher under black polyethylene mulch in comparison those under mulching with sugarcane trash, paddy straw, saw dust, dry grasses and unmulched control (Ali and Gaur, 2007). The black polyethylene film mulch enhanced flowering in Chausa and Langra cultivars of mango when compared with non-mulched trees (Singh et al., 2009) Fruit set and fruit retention In apple, mulching with black polythene gave highest fruit set and yield in comparison to hay grass mulch (Thakur et al., 1993). Trees of Chausa and Langra cultivars of mango registered higher fruit retention when mulched with black polyethylene film compared with non-mulched trees (Singh et al., 2009) Fruit yield Application of black plastic mulch to the vines of Barbera grape established on A X RC rootstocks in Mexico during resulted in increased cumulative fruit yield over 4 years by 4.85 t/ha (55.6 %) in comparision to vines maintained without mulching(ibarra et al., 1996). In pomegranate (Punica granatum) cv. Ganesh, the highest yield of fruits (67-74 Kg/ plant) was obtained from the plants under mulching + irrigation treatment, followed in the decreasing order by those given treatments of irrigation alone and mulching alone (Gupta et al., 1999). Moore-Gordon et al. (1997) reported increase in fruit yield of avocado cv. Hass with mulching. Dale (2000) reported 26 per cent increase in fruit yield of Black currant by the use of black plastic mulch over no mulch treatment. 57

78 Mulching mitigated the negative effects of water stress on plant growth and fruit yield in field grown strawberry (Kirnak et al., 2001). In grape cv. Perlette, the fruit cluster weight and yield per vine were highest when vines were irrigated at soil moisture tension of 20 KPa, whereas, straw and plastic mulching significantly increased fruit weight and number of fruit clusters per vine over the un-mulched control (Phadung et al., 2005). In acid lime, the highest fruit yield was recorded with black polyethylene (100m) mulch (13.28 q tree -1 ) followed by grass mulching (Shirgure et al., 2005). Li et al. (2011) observed higher yield in wine grapes with using plastic film mulching than without mulch treatment SOIL MOISTURE Haynes (1987) observed higher soil moisture content under polyethylene mulching than the un-mulched conditions in arable land. In a trial on different mulching treatments viz., 200 and 400 gauge black polyethylene film, a Macrotyloma uniflorum cover crop, coir, dry grass, double cover crop (Macrotyloma uniflorum + Vigna sinensis) and Eucalyptus leaves when applied to the trees of sapota cv. Kalipatti, the greatest percentage of soil moisture was recorded with the mulching of 400-gauge black polyethylene film (Reddy and Khan, 1998). The kiwifruit vines mulched with bahia grass resulted in higher soil moisture content during dry season of mid-summer (Xu et al., 2001). The organic mulch treatment increased the soil moisture content in avocado and citrus (Faber et al., 2003). Phadung et al. (2005) observed rapid depletion in the soil moisture content following irrigation at 20 and 40 kpa, when mulch was not applied around the vine basins of grape cv. Perlette. In Lal Sundari cultivar of mango, the maximum soil moisture content was obtained with organic mulching + 75% pan evaporation replenishment (PER) treatment in comparison to organic mulching + 25% PER and organic mulching + 50% PER (Kumar et al., 2008) CANOPY TEMPERATURE In kiwifruit cv. Hayward, the soil under control vines warmed up and cooled down earlier than soil under polythene mulch during the day, which resulted in a diurnal oscillation of the temperature differential between control and mulched vines (Snelgar et al., 1999). In mango cv. Keitt, the canopy 58

79 temperature was not affected by mulch treatment (Shahak et al., 2001). In olive cv. Konservolea, the leaf temperature was increased in the presence of mulch (Pliakoni and Nanos, 2012) ANATOMICAL AND PHYSIOLOGICAL CHARACTERISTICS AND WATER RELATIONS Stomatal studies and leaf water potential In mango cultivars Chausa and Langra, black polyethylene film ( 100 micro thick) mulch resulted in increased size of stomatal pores in the leaves (Singh et al., 2009). In grape cv. Perlette, the leaf water potential decreased in unmulched and water stressed vines ( irrigated at 20 and 40 kpa soil moisture tension) compared with mulched and well irrigated vines (Phadung et al., 2005). In sapota cv. Kalipatti, among different mulching treatments viz., 200 and 400 gauge black polyethylene film, a Macrotyloma uniflorum cover crop, coir, dry grass, double cover crop ( Macrotyloma uniflorum + Vigna sinensis) and Eucalyptus leaves, mulching with 400-gauge black polyethylene film resulted in reduction in stomatal resistance (Reddy and Khan, 1998) Transpiration rate The plastic or straw mulch is an efficient practice, which can alter water distribution between soil evaporation and plant transpiration (Raeini- Sarjaz and Barthakur, 1997). Costa et al. (2003) observed that under reflecting mulch treatment the transpiration rate increased in the morning hours and decreased in the afternoon in Hayward cultivar of Kiwifruit. In olive cv. Konservolea, the presence of reflective mulch decreased the transpiration rate in comparison to unmulched control (Pliakoni and Nanos, 2012) Photosynthetic rate Costa et al. (2003) observed that the reflecting mulch accelerated the photosynthetic rate during the day in Kiwifruit cultivar Hayward. In high bush blueberry, mulching increased the photosynthetic rate and respiration in plants in comparison to control (Wu- Lin et al., 2006). In five year old peach trees, the photosynthetic rate was observed higher with reflective film mulch over the unmulched control (Zhou and Wang, 2009). In olive cv. Konservolea, the 59

80 photosynthetic rate was not affected by the presence of mulch (Pliakoni and Nanos, 2012) Chlorophyll content Kirnak et al. (2001) in a study on the use of five in-situ moisture conservation treatments viz., bare soil + water stress (WS), bare soil + unstressed (control), black polyethylene mulch + water stressed (BPM +WS), wheat straw mulch + water stressed (WSM + WS), wheat straw mulch + black polyethylene mulch + water stressed (WSM + BPM + WS) applied to the plants of Oso Grande strawberry, observed that the black polyethylene mulch and wheat straw mulch improved the chlorophyll concentrations in the leaves of stressed plants significantly in comparison to plants under bare soil + water stress, bare soil + unstressed (control) and the wheat straw mulch + black polyethylene mulch + water stress treatments Chlorophyll stability index The chlorophyll stability index was higher under water stress in cotton plants (Ananthi et al., 2013). However, Ramesh and Devasenapathy (2006) reported that the mulching treatment increased the chlorophyll stability index in cowpea Proline The mulch treatment resulted in lower proline content compared to traditional farmers practice in cowpea (Ramesh and Devasenapathy, 2006). In Anna apple, the deficit irrigation significantly increased the leaf proline content whereas, soil mulching resulted in significant reduction in leaf proline content (Mikhael, 2007). Jiang et al. (2012) reported reduction in proline content in leaves of maize with film mulch removal at different stages viz., seedling, jointing and tasseling stage under water stress condition Relative water content In a study on sapota cv. Kalipatti, different mulching treatments viz., 200 and 400 gauge black polyethylene film, a Macrotyloma uniflorum cover crop, coir, dry grass, double cover crop (Macrotyloma uniflorum + Vigna sinensis) and Eucalyptus leaves and control (no mulch) were applied, wherein the use of

81 gauge black polyethylene film resulted in maximum increase in leaf relative water content in comparison to other mulch treatments (Reddy and Khan, 1998) Cytokinin and abscisic acid content Luo et al. (2013) reported increased ABA and reduced zeatin riboside contents in cotton leaves and roots under increased drought stress condition whereas, the increased soil moisture content after re-watering resulted in increased zeatin riboside content and did not affect the ABA content of cotton leaves and roots Leaf nutrient status Mulches conserved moisture by reducing evaporation, increasing infiltration of water and soil temperature and decreasing soil temperature fluctuations, enhancing mineral nutrient availability and preserving or improving soil structure (Libik and Wojtaszek, 1973). These also encourages the proliferation of feeder roots, consequently might promote efficient uptake of plant nutrients (Gregoriou and Rajkumar, 1985). In a field experiment in apple, Neilson and Hogue (1985) demonstrated that black plastic mulch increased leaf nitrogen concentration in comparison to sod mulch. Grass mulch markedly increased N, P, K, Ca and Mg content in the apple leaves (Raina, 1991). An experiment on different types of mulching and water stress in strawberry cv. Oso Grande revealed that mulching particularly black polyethylene mulch and wheat straw when spread over the soil of stressed plants enhanced the concentrations of N, P, K, Ca and Mg in leaf, however, their concentration was still lower than those in the control (Kirnak et al., 2001). In aonla ( Emblica officinalis G.) cv. NA 7, use of 8cm thick farmyard manure increased the leaf P, K, Ca and Mg values whereas, paddy straw mulch increased the level of leaf N to the maximum extent, in drip irrigated trees (Shukla et al., 2001). Faber et al. (2003) reported increased leaf nutrient s tatus in avocado and citrus with organic mulches FRUIT QUALITY Cortez et al. (1995) observed 41per cent reduction in non- marketable fruits of strawberry cv. Campinas by the use of black polyethylene mulch. In 61

82 water stressed strawberry cv. Oso Grande plants, mulching with black polyethylene and wheat straw resulted in a marked improvement in fruit size (Kirnak et al., 2001). The black polyethylene mulch and grass mulch resulted higher fruit weight, acidity and juice content in acid lime (Shirgure et al., 2005). In drip irrigated strawberry cv. Chandler plants, the berry weight, volume and size were increased by mulching with hay by and 43.50%, respectively compared to hay mulched rainfed plants (Sharma et al., 2005). In another study, plants of highbush blueberry ( Vaccinium corymbosum L.) cv. Elliott were irrigated by drip, overhead sprinklers and microsprays at 50, 100 and 150 per cent of the crop evapotranspiration requirement (ETc) and it was observed that the use of mulch caused higher increase in berry weight in plants irrigated at 100 per cent ETc than those irrigated at 50 per cent ETc however, the berry weight was statistically at par between plants irrigated at 100 per cent and 150 per cent Etc. (Bryla et al., 2009). In five-year-old peach, spreading of reflective film mulch over the tree basin decreased the fruit firmness in comparison to non-mulched control (Zhou and Wang, 2009). In mango cv. Keitt, the fruit TSS was more in mulched trees in comparison to non-mulched control (Shahak et al., 2001). Hasan et al. (2002) observed that the mulching of the plants of dwarf Cavendish banana cv. Giant Governor with black polyethylene resulted in improvement in TSS content over untreated plants. In grape cv. Cabernet Franc, the reflective mulch enhanced the quantity and quality of light into the fruiting zone, advanced the veraison and in general increased degrees Brix, total phenolics, flavonoids and anthocyanins in berries at harvest ( Coventry et al., 2005). In strawberry cv. Chandler, the TSS content in berry was increased to per cent under rainfed + unmulched treatment while, the minimum (7.66%) TSS was observed by the drip irrigation + hay mulch treatment (Sharma et al., 2005). In Perlette cultivar of grape, fruit TSS content was observed higher when the irrigation treatment applied at the soil moisture tension of 20 k Pa, however, different mulching treatments could not exerted significant effect on fruit TSS content (Phadung et al., 2005). The total soluble solids content was increased by the use of 100m black polyethylene mulch and grass mulch in acid lime (Shirgure et al., 2005). Similarly, watering 62

83 and mulching treatments exhibited no effect on total soluble solids and acidity in Jackfruit (Ghosh and Bera, 2006). In dwarf Cavendish banana cv. Giant Governor, fruits from plants under the black polyethylene mulch had higher total sugars in comparison to fruits from non-mulched plants (Hasan et al., 2002). In Guava cv. L-49, the maximum reducing sugar was obtained in fruits from plants under black polythene mulch in comparison to those from plants under different organic mulches like saw dust, dry leaves of guava, paddy straw, sugarcane trash (Maji and Das, 2008). In a study on various mulching and irrigation treatments in wine grape, the sugar content was observed higher in berries from vines with clean basins (no mulch), followed by those under the treatments of plastic film mulch along with 240 mm drip irrigation; plastic film mulch along with 300 mm irrigation, plastic film mulch along with 360 mm irrigation and plastic film mulch with 420 mm irrigation, in the decreasing order (Li et al., 2011). The different types of mulching treatments viz., concrete mulch, plastic film mulch and straw mulch had no effect on fruit titratable acidity of ber (Zizyphus jujube Miller) plants(sun et al., 2012). Cortez et al. (1995) observed no significant effect of mulching on ascorbic acid contents of strawberry cv. Campinas when low density black polyethylene film or with polypropylene film along with sprinkler irrigation were applied. However, the ascorbic acid content was observed higher under black polyethylene mulch than the clear polyethylene or paddy straw mulch in Chandler cultivar of strawberry (Singh et al., 2005). In Guava cv. L-49, the higher ascorbic acid content was obtained with black polythene mulching in comparison to organic mulching with saw dust, dry leaves of guava, paddy straw, sugarcane trash (Maji and Das, 2 008). Kour and Singh (2009) conducted an experiment in strawberry cv. Chandler by applying six mulch treatments viz., black polythene, transparent polythene, paddy straw, saw dust, dry grasses and un-mulched control and observed the highest fruit ascorbic acid content following the use black polythene mulch, which was however, statistically at par other mulch treatments but significantly superior over the control. 63

84 Chapter-3 MATERIALS AND METHODS The present investigations on the Studies on water relations and deficit irrigation in kiwifruit ( Actinidia deliciosa Chev.) were undertaken in the Department of Fruit Science, Dr. Y. S. Parmar University of Horticulture and Forestry, Nauni-Solan, Himachal Pradesh during the years 2011 and The details of material used and methodologies employed are presented in this chapter. 3.1 LOCATION The experimental vineyard is situated at an elevation of about 1242 m above mean sea level on the Northern aspect and lies at N and E longitude. 3.2 CLIMATE The experimental area falls under sub-temperate sub-humid climate. Summers are moderately hot during May-June and winters are severe during December- January. The average annual rainfall of this area is about cm, the major part of which is received during July to September. The temperature and rainfall data during the period of study are given in Annexure- II. 3.3 SELECTION OF PLANT MATERIAL Twenty five-year-old uniform vines of kiwifruit cultivars Allison, Abbott, Monty, Hayward and Bruno planted at 6x4 m spacing and training on T-bar system were selected for the study. Twenty vines comprising four plants of each cultivars Allison, Abbott, Monty, Hayward and Bruno were selected for the experiment I. For the experiment II, twenty one vines of cultivar Allison were selected. Uniform cultural practices were given to each vine during the course of study.

85 3.4 EXPERIMENTAL DETAILS The entire technical programme as envisaged in these investigations has been divided into two separate experiments. The details of the experiments are given as under: Experiment 1: Screening of kiwifruit cultivars for water deficit conditions Number of cultivars: 5 - Allison, Hayward, Abbott, Monty and Bruno Irrigation treatments: 2 - At 60% and 80% Field capacity Replications: 4 Experimental Design: Randomized Block Design (RBD) Experiment 2: Effect of in situ moisture conservation and deficit irrigation on growth, water relations and yields in kiwifruit Cultivar: Allison Treatments: 7 Treatment Details: T 1 - Irrigation at 80% Field capacity T 2 - Irrigation at 60% Field capacity T 3 - Irrigation at 40% Field capacity T 4 - Irrigation at 60% Field capacity + Mulching with grass (10 cm thick) T 5 - Irrigation at 60% Field capacity + Black polythene mulching (200 gauge thick) T 6 - Irrigation at 40% Field capacity + Mulching with grass (10 cm thick) T 7 - Irrigation at 40% Field capacity + Black polythene mulching ( 200 gauge thick) Replications: 3 Number of vines per replication: 1 Experimental design: RBD Time of application of mulching: Mid- March. 65

86 3.5 METHOD AND SCHEDULE OF IRRIGATION Basins of experimental vine measuring 3x2 meter size were prepared at the start of the experiment in March. All the basins were properly leveled. First irrigation was 330 litres per vine of all the treatments by flooding method to bring the soil to field capacity level. Then the soil moisture was allowed to deplete to 80, 60 and 40 per cent of field capacity in the respective treatments and then, it was again brought to field capacity by applying a measured quantity of water. The quantity of water applied to bring the soil moisture to field capacity in the vine basins during each irrigation in different treatments was determined with the aid of soil moisture characteristic curve Soil moisture characteristic curve The composite soil samples from vine basins (0-60 cm) were taken. These samples were saturated with water for 24 hours and then subjected to -0.3, -0.5, - 1.0, -5.0, and atmospheric pressure using Pressure Plate apparatus (Richard, 1949). The moisture contents of the soil retained at different atmospheric pressure were determined by gravimetric method and expressed in per cent on dry weight basis (Table 3.1). On the basis of these observations, soil moisture characteristics curve was prepared to determine the amount of water retained by soil at different soil moisture levels, which served as a guideline to calculate the quantity of water to be applied to bring the moisture in soil at field capacity. Table 3.1 Soil moisture level at different atmospheric tensions in kiwifruit vineyard Tension (bars) Moisture (%)

87 3.5.2 Calculation of quantity of water The quantity of water applied to each experimental vine to bring the soil moisture to field capacity from 20, 40 and 60% depletion level was calculated as under: Total quantity of water applied per vine = Ax d Where, A= Basin area to be irrigated d= Depth of irrigation water (cm) The depth of irrigation water for each application was calculated by the following formula: Where, Depth of irrigation water (d) = Pw = Moisture percentage to be raised Pw x Bd x D 100 Bd = Bulk density of the soil (1.31 gm/ cm 3 ) D = Depth of root- zone to be moistened (60 cm) The quantity of water applied under each treatment on the basis of the above calculation was 198.1, and litres at 80, 60 and 40 per cent of field capacity levels, respectively Frequency and number of irrigation Frequency of the irrigation applied under different treatments was calculated by counting the number of days between two consecutive irrigations. The number of irrigations applied under these treatments over the growing period was calculated. 3.6 OBSERVATIONS RECORDED VEGETATIVE GROWTH Shoot growth Ten shoots from the current season s growth were randomly selected from the periphery of each vine. The length of these shoots was measured with a measuring tape at the end of growing period and expressed in centimeters (cm). 67

88 Length of internodes The internodes length of ten randomly selected current season s shoots on each experimental vine was calculated by dividing the shoot length measured at the end of growing season with total number of internodes and expressed in centimeters (cm) Leaf area The leaf area was determined by using leaf area meter, Li- COR Model Ten leaves were collected at random from the periphery of each vine. The cumulative area obtained from the leaf area meter was averaged and expressed in square centimeter (cm 2 ) Leaf thickness Twenty five fully grown healthy and disease free leaves of current season s growth were randomly sampled from the entire periphery of each experimental vine to record the leaf thickness. Surfaces of all the twenty five leaves were joined together, then their thickness was measured with the Digimatic Calliper (Mitutoyo, Japan) and the readings were averaged and expressed in millimeter (mm) Leaf yellowing The observations on the leaf yellowing were recorded by counting the number of leaves that turned yellow on the five selected fruiting arms of each vine. Total number of leaves on the selected branches was also counted and leaf yellowing was calculated by using the following formula and expressed in percentage. Leaf yellowing (%) = Number of yellow leaves Total number of leaves x FLOWERING AND FRUITING Bloom intensity The number of flowers on four selected fruiting arms from each treated vine was counted and the cross sectional area of these fruiting arms in square 68

89 centimeters was recorded. From these observations, the bloom intensity was determined as per formula given below: Bloom intensity = Number of flower per fruiting arm Cross sectional area of fruiting arm x100 The bloom intensity was expressed as number of flower/ cm 2 arm cross sectional area. The results were expressed in per cent Fruit set To study the percentage of fruit set, ten fruiting arms of equal length were selected on each vine in all possible directions. The number of flowers on these fruiting arms was counted and after 10 days of full bloom, the number of fruits was also counted. The per cent fruit set was calculated as per formula given below: Fruit set (%) = Number of fruit set on the fruiting arm Total number of flowers present on the fruiting arm x Fruit retention To study the percentage of fruit retention, ten fruiting arms of equal length were selected on each vine in all possible directions. The number of fruit set on the arms was counted after fruit setting and the number of fruits retained at the time of harvest was also counted. The per cent fruit retention was calculated as per formula given below: Fruit retention (%) = Fruit yield Total yield Number of fruits retained on the fruiting arm Total number of fruit set on the fruiting arm x100 The total yield of kiwifruit under different treatments was determined on the basis of total weight of fruits harvested from the vine under each treatment and average yield per vine was calculated. The yield was expressed in kilogram per vine (kg/vine). 69

90 A Soil moisture B Canopy temperature C Leaf water potential D Photosynthetic rate E Grass mulch F Black polythene mulch Plate 1 Field observations (A-D) and use of mulches (E-F)

91 Graded yield On the basis of weight, the harvested fruits were classified into four grades viz; A ( >70g), B (50-70g), C (<40-50g) and D (<40g). The yield of different grades was expressed in percentage of the total yield SOIL MOISTURE Soil moisture data were recorded using Aqua Pro Soil Moisture Probe by lowering the probe at 30 and 60 cm depth down the access tubes installed in the basins of each experimental vine. The readings were taken at fortnightly intervals during the growing season and average values were expressed in percentage (Annexure III) CANOPY TEMPERATURE Infra red thermometer was used to record temperature from all the four sides of vine canopy from a distance of five meter. The temperature was recorded at 12:00 am from the month of May to August at weekly intervals. The average values were expressed in degree Celsius (Annexure IV) ANATOMICAL, PHYSIOLOGICAL AND BIOCHEMICAL STUDIES Stomatal studies Five mature leaves from the middle of current season s growth were selected from each experimental vine on a sunny day in mid-july between 9:00-11:00 a. m. A thin layer of quick fix was smeared in the middle of the laminas on the abaxial (lower) surface of the leaf as suggested by Beakbane and Majumdar (1975) and Pathak et al. (1976). The leaves were then collected in paper bags and brought to the laboratory. The dried film from the lower surface of the leaf bearing the impression of the leaf cuticular layer was removed, placed on a dry glass slide and a cover slip was mounted on it with DPX adhesive Stomata size The stomata size (length and width of pore) was recorded with the help of Leica Stereoscopic Microscope and expressed in µm as per the technique described by Beakbane and Majumdar (1975). 70

92 Stomatal density The slides prepared for stomatal studies were examined under a low power objective lens to locate area of maximum stomatal density. Five microscopic fields of the slides were examined at 40x 10x magnification and number of stomata viewed per field was recorded. The results were expressed as frequency of stomata per unit area of the leaf at 40x 10x Leaf water potential Leaf water potential was recorded with the help of portable Plant Water Status Console in May and June. Water potential readings were recorded between 10:00 a.m. to 12:00 a.m. by placing freshly detached leaf in pressure chamber. Procedure Freshly detached leaf was inserted into the pressure chamber through the two halves of a rubber stopper of the upside down apparatus in such a way that its blade was inside the chamber, while cut end of petiole protruded outside of the apparatus. The metal retaining plate was placed over stopper and then the bolts tightened by turning it with hand until they were snug and it again tightened using the Allen wrench until they were firmly tightened. The pressure was applied slowly inside the bomb using the pressure regulator of the apparatus. While, observing the cut surface of the petiole carefully, slowly increased the pressure in the bomb until the cut surface changed dramatically in appearance. Originally the surface had a dull white appearance and when the pressure in the bomb equaled the water potential of the sample, the xylem fluid returned to the cut surface giving it water saturated, glossy appearance. At this stage water potential reading was recorded on the pressure gauge. Readings of five leaves per replication were taken separately; the results so obtained were averaged and expressed in bars Stomatal resistance, transpiration rate and photosynthetic rate Stomatal resistance, transpiration rate and photosynthetic rate were recorded when soil moisture content under the respective treatments reached the 71

93 required tension (i.e. 80% of FC, 60% of FC and 40% of FC). Ten mature leaves from each experimental vine were selected randomly from all over the tree periphery. The observations were recorded during active growth periods between 9:00 to 11:00 AM with the help of LI-COR 6200 Portable Photosynthesis System. The results were expressed in s cm -1, m mol/m 2 /S and µmol/m 2 /S for stomatal resistance, transpiration rate and photosynthesis, respectively Chlorophyll content A sample of ten representative fully grown leaves from the current season s growth of each vine was detached in the morning hours, in the first week of August (Halfacre et al., 1968), immediately placed in ice box and brought to the laboratory. The samples were then kept in the refrigerator below 0 0 C to avoid degradation of chlorophyll pigments. Extraction Leaves from each sample were washed and chopped into fine pieces under subdued light and 100 mg of chopped material was placed in vial containing 7 ml of dimethyl sulphoxide (DMSO). The contents of the vials were incubated at 65 0 C temperature for 30 minutes and then extract was transferred to graduated test tube and final volume was made to 10 ml with dimethyl sulphoxide (Hiscox and Isralistan, 1979). Estimation Optical density (OD) of the above extract was recorded on Spectronic-20 D at 645 and 663 nm wave length against a DMSO blank and total chlorophyll content was calculated by using the following formula: Total Chlorophyll (mg/g) = Where, V= Volume of extract used A= Length of light path in cell (1cm) W= Weight of the sample (g) A 645 = Absorbance at 645 nm wavelength A 663 = Absorbance at 663 nm wavelength 20.2 A A 663 x V A x 1000 x W 72

94 The results were expressed as chlorophyll content in mg/g of fresh weight Chlorophyll stability index The chlorophyll stability index (CSI) was determined as per the method suggested by Murthy and Majumder (1962). One gram of fresh leaf sample was soaked in 25 ml of distilled water and then heated at 65 ± 1 0 C for one hour in a water bath. Another, one gram of fresh leaf sample was taken as control from unheated sample. The extracts from heated and unheated leaves were made in 40ml of acetone (4:1) in a mortar and pestle and filtered. Absorbance of the supernatant from heated and unheated leaf samples was recorded at 652 ηm on UV-spectrophotometer. The difference between the two readings was calculated and CSI was deduced using the following formula: CSI (%) = Unheated leaf absorbance Heated leaf absorbance Unheated leaf absorbance x Proline content The leaf proline content was estimated according to the method described by Bates et al. (1973). (i) Reagent and Procedure: Acid-ninhydrin solution was prepared by dissolving 1.25 g ninhydrin in 30 ml of glacial acetic acid and to this solution, 20 ml of 6 M orthophosphoric acid was added with agitation. (ii) Sample preparation: For estimation of proline and free amino acids, disease free immature but fully expanded leaves from the middle of current season s growth were collected in appropriate quantity in an ice box, during the month of mid- July and were brought to the laboratory. Leaves were washed in distilled water and then in doubled distilled water and immediately kept in deep freezer. (iii) Estimation: Leaf tissue (0.5 g) was macerated with 10 ml of three per cent aqueous sulphosalicyclic acid and filtered with Whatman No. 1 filter paper. The residue was extracted twice with 10 ml of three per cent aqueous sulphosalicylic acid and different fractions of filtrates were pooled. To two ml of filtrate, two ml of each glacial acetic acid and acid ninhydrin solutions were added with complete 73

95 mixing. The mixture was boiled for one hour on water bath and then reaction was terminated by placing test tubes on ice bath. After cooling, four ml of toluene was added and mixed vigorously for sec. The chloromophore (toluene) la yer was aspirated and warmed to room temperature. The absorbance of red colour was read on UV spectrophotometer at 520 nm against reagent (acid - ninhydrin solution) blank. The amount of proline in the sample was calculated using standard curve prepared from pure proline Free amino acids Free amino acids were estimated as per the method of Lee and Takahashi (1966). (i) Reagents: The following reagents were used for the estimation of free amino acids in kiwifruit. a) 0.5 M citrate buffer, ph 5.5: Two stock solutions were prepared: 1) 0.5 M solution of citric acid: g of citric acid was dissolved in one litre of water. 2) 0.5 M solution of sodium citrate (C 6 H 5 O 7 Na 3. 2 H 2 O) : 147 g of sodium citrate was dissolved in one litre of water. The ph of citrate buffer was adjusted to 5.5 by mixing 4.8 ml of 0.5 M citric acid and 15.4 ml of 0.5 M sodium citrate. b) Ninhydrin solution: 1% ninhydrin solution in 0.5 M citrate buffer. c) Glycerol solution: 100% glycerol was used as such. d) Glycerol mixture: Reaction mixture of ninhydrin- citrate (1% ninhydrin solution in 0.5 M citrate buffer) was mixed with glycerol and citrate buffer in the ratio of 5:12:2 (Ninhydrin: Glycerol: Citrate buffer) and the ph of solution was adjusted to 6.0 with the help of sodium citrate. e) Glycine standard solution (10 to 100µg/ml): 100 mg glycine was dissolved in 100 ml water. 74

96 (ii) Procedure Extraction: Thirty mg of the dry material of each sample was extracted in two ml of 80% ethanol and centrifuged at 5000g for 10 min. The extraction was again repeated with two ml of 80% ethanol, centrifuged at 5000 g for 10 minutes, so as to allow complete removal of amino acids from the samples. Supernatants were pooled and then reduced to dryness at 60 0 C. The final volume of the solution was made to two ml with 80% ethanol. Estimation: Take 0.2 ml of the extract and to it 5ml each of ninhydrin, citrate and glycerol mixture was added. The contents were heated in a boiling water bath at C for 12 minutes and then cooled to room temperature. The absorbance was read on Spectrometer at 570 nm. Quantity of total free amino acids was calculated from standard curve prepared with pure glycine Relative water content The relative leaf water content (RWC) was determined in accordance with the method suggested by Barrs and Weatherley (1962) after recording fresh, dry and saturated weights of 10 leaf discs. At first, the fresh weight (FW) of discs was recorded and then discs were floated on water in darkness for six hours at a temperature of C. The discs were blotted to dry the surface moisture and the turgid weight (TW) was determined. The dry weight (DW) was measured after drying the discs for 24 hours in hot air oven at C. The relative water content (%) was calculated by using formula given below: Relative water content (%) = Xylem development FW-TW TW-DW x Fixing of specimens for anatomical studies In the month of May during water deficit condition, stem sections of one cm length of current season growth were collected with the help of pruning scateur and put in specimen jars containing formalin aceto alcohol (FAA) solution (formaldehyde, glacial acetic acid, distilled water and absolute alcohol in 75

97 the ratio of 1:1:9:9). These specimens were stored in this fixative till their subsequent processing Dehydration The specimens of desired sizes were dehydrated in a graded series of tertiary butyl alcohol (TBA) as suggested by Jensen (1962). The composition of different grades of TBA used for dehydration of the stems sections along with relative duration for which specimens were kept in these formulations are given below: Grade Composition (ml) Duration (hrs) TBA Absolute alcohol Distilled water I II III Overnight IV V VI Overnight Waxing The specimen s tube containing stem sections (submerged in pure TBA) was placed in oven at degree Celsius. Molten paraffin wax (2-3 drops at a time) was poured in specimen tube repeatedly at an interval of minutes for a number of times. Excess solution was decanted and this process was continued till the complete evaporation of TBA from the specimen tube. Then, the whole of the solution was poured out and molten wax was put on it. Embedding The specimens were embedded in a petridish by pouring the molten paraffin wax and the specimens were arranged in the required position with the help of forceps. Microtomy The paraffin block containing specimen (stem sections) after trimming to required size and shape was fixed on a wooden block. Transverse sections of stems were cut at µm using NIPPON Plant Microtome Model MTH 1. 76

98 Mounting of sections The slides were smeared with a drop of Haupt s adhesive to ensure proper mounting of paraffin ribbons containing thin sections of stem portions of previous season s growth. The composition of this medium was as under: Gelatin : 1g Phenol : 2g Glycerine : 15 ml Distilled water : 100 ml A few drops of formalin solution were placed on the slide and the ribbon was floated on the fluid. The slide was then placed in hot air oven which slowly warmed at a temperature of 50 o C so as to permit proper stretching of paraffin ribbon and ensure proper placing of the sections on the slide. The aqueous solution was then slowly drained out without disturbing the section. Dewaxing The prepared slides were then immersed in the following solutions to obtain dewaxing of the sections. Composition of dewaxing media Duration 30 % alcohol 2-3 minutes 50 % alcohol 2-3 minutes 75 % alcohol 2-3 minutes 95 % alcohol 2-3 minutes Absolute alcohol-i 2-3 minutes Absolute alcohol-ii 2-3 minutes Absolute alcohol: Xylene (3:1) 2-3 minutes Absolute alcohol: Xylene (1:1) 2-3 minutes Absolute alcohol: Xylene (1:3) 2-3 minutes Xylene-I 15 minutes Xylene-II 15 minutes 77

99 Staining The dewaxed slides were stained as per the schedule given by Johnson (1940) and Sass (1946). Table 3.2 The details of staining procedure for anatomical studies of kiwifruit shoot Composition of staining media Duration Saffranine 30 minutes Distilled water Washing 30% alcohol 2-3 minutes 50% alcohol 2-3 minutes 75% alcohol 2-3 minutes 95% alcohol 2-3 minutes Fast green 5-10 seconds Absolute alcohol-i 2-3 minutes Absolute alcohol-ii 2-3 minutes Absolute alcohol: Xylene (3:1) 2-3 minutes Absolute alcohol: Xylene (1:1) 2-3 minutes Absolute alcohol: Xylene (1:3) 2-3 minutes Xylene-I 15 minutes Xylene-II 15 minutes Mounting After the tissue had been stained, one drop of DPX mounted on the slide was placed and then the section was covered with a cover slip. Microscopic studies of anatomical characteristics namely, number of primary xylem vessels and development of secondary xylem were made with the help of LICA-DMLB compound microscope, using LICA imaging and analysis software Endogenous hormones (i) Sample collection: For the estimation of cytokinin and abscisic acid (ABA) in the leaves, immature but fully expanded leaves from the middle of current season growth were collected in ice box during the month of mid-june and were brought to the laboratory. Leaves were washed in distilled water and then with double distilled water and then immediately kept in deep freezer. 78

100 (ii) Extraction of Cytokinin Cytokinins were extracted from the plant tissues as per procedure described by Sridhar et al. (1978). Twenty five grams of fresh leaf tissues were homogenized in 25 ml of Mcllvaine s buffer (ph 5.6) in a blender. Preparation of Mcllvaine s buffer (ph 5.6): This buffer is also known as phosphate citrate buffer. Two stock solutions were prepared: 1) 0.2 M solution of Na 2 HPO 4.2H 2 O: 35.61g of this solution was dissolved in one litre of water. 2) 0.1 M solution of citric acid: g of citric acid was dissolved in one litre of water. For the preparation of Mcllvaine s buffer of ph 5.6, ml of 0.2 M of Na 2 HPO 4 and 8.40 ml of 0.1 M citric acid were mixed. To this mixture, 150 ml of ethanol was added and after 6-8 hours, contents were centrifuged at 2000 g for 20 minutes. The supernatant was decanted and evaporated to 10 ml under reduced pressure on a rotary evaporator at 40 o C. The ph of the solution was adjusted to 2.9 with 1N HCl. The extract was then shaken in a separatory funnel thrice with 10 ml of diethyl ether to remove chlorophylls, auxins and gibberellins. The ether layer was discarded and the ph of the aqueous solution was adjusted to 7.8 with 1N NaOH. The 5 ml portions of n-butanol were used six times for extraction in a separatory funnel. The butanol layers were pooled and evaporated to dryness under reduced pressure at 40 o C. The residue was dissolved in two ml of buffer for the estimation of zeatin riboside. (iii) Extraction of ABA The procedure for the extraction of ABA was the same as described by Mohanty et al. (1979). According to this method, 20 g of fresh leaves were taken and homogenized in 60 ml of 80 per cent methanol using a blender and the homogenate was filtered through Buchner funnel using Whatman No. 41 filter paper. The residue was washed with excess method. The filterate and washings were pooled and their volume was reduced to 15 per cent of the original volume at 40 o C. The ph of the concentrated extract was adjusted to 8.5 with 1 N 79

101 NaHCO 3. The alkaline extract was partitioned with petroleum ether thrice and the petroleum ether fraction was discarded. The ph of the aqueous fraction was readjusted to 2.7 with 1N HCl. Again partitioning of the acidic extract was done twice with ethyl acetate. The ethyl acetate fractions were pooled and evaporated to dryness at 40 o C in a rotary evaporator. The residue was dissolved in minimum volume of methanol and used for chromatographic separation of ABA. (iv) Estimation High pressure liquid chromatography technique (Waters HPLC) was used for the estimation of cytokinin and ABA (Weiler, 1982) in plant tissue. The extracted samples were then injected in the HPLC instrument by using methanol (80:20) as a mobile phase. Waters HPLC plotted graphs according to the concentration of hormones present in it, which was viewed on the computer and compared with the standards. The quantities of cytokinin (zeatin riboside) and ABA were expressed as ρg/g and ɳg/g fresh weight, respectively Nutrient status Leaf sampling procedure In order to estimate the leaf nutrient status of experimental trees, mature leaves with petioles were sampled in mid- August from middle portion of the current season s shoot, all around the periphery of the vine (Chapman, 1964). The samples were processed for nutrient analysis as per procedure outlined by Kenworthy (1964). Leaf samples were collected, brought directly to the laboratory, thoroughly washed by 0.1 N HCl, distilled water and finally with double distilled water. The washed samples were first air dried in the shade by spreading on clean blotting papers and final drying was accomplished in an oven at 65 0 C for 48 hours (Chapman, 1964). The dried samples were then ground and stored in butter paper bags for chemical analysis Digestion of leaf samples: For estimation of nitrogen, the digestion of one gram dried leaf samples was carried out in concentrated sulphuric acid in the presence of a digestion mixture of following chemicals: 80

102 Potassium sulphate : 400 parts Copper sulphate : 20 parts Mercuric oxide : 3 parts Selenium powder : 1 part For the estimation of other elements, the samples were digested in diacid mixture prepared by mixing nitric acid and perchloric acid in the ratio of 4:1, taking all relevant precautions as suggested by Piper (1966) Determination of leaf N, P, K, Ca and Mg Nitrogen After digestion, nitrogen was estimated by Micro-kjeldahl method (A.O. A. C., 1980). Twenty five millilitres of 4 per cent boric acid solution containing mixed indicator (bromo cresol green + methyl red) was taken in a conical flask and was placed in such a way that condenser outlet of distillation apparatus was dipped into boric acid solution. Then ten ml of the aliquot (digested) was taken and transferred to distillation flask of Micro-kjeldahl distillation apparatus. After adding the aliquot, the funnel of the apparatus was washed with 2-3 ml of distilled water and ten ml of 40 per cent NaOH was added. Ammonia (NH 3 ) thus liberated was absorbed into the boric acid in conical flask. After completion of distillation, boric acid solution was titrated against standard H 2 SO 4 solution and nitrogen content was calculated on the basis of H 2 SO 4 solution used to neutralize the evolved ammonia and expressed in percentage on the dry weight basis. Phosphorus Total phosphorus was determined by Vanado- Molybdate- Phosphoric Yellow colour Method (Jackson, 1973). Five millilitres aliquot (digested) was pippetted out into 25 ml volumetric flask and 5 ml of vanadomolybdate reagent was added. Then solution was diluted to 25 ml with distilled water and allowed to develop colour for half an hour. After development of colour, absorbance was recorded on Spectronic-20 D at 470nm wavelength and a blank was run simultaneously to adjust the zero absorbance. Phosphorus content was then calculated from standard curve of phosphorus and expressed in per cent on dry weight basis. 81

103 Potassium, calcium and magnesium Potassium, calcium and magnesium in the leaf extract were estimated on Perkins Elmen Atomic Absorption Spectrophotometer and expressed in percentage FRUIT QUALITY The fruit samples for physic-chemical analysis were collected when the fruits had attained full maturity. Ten fruits were collected randomly from all sides of the vines and then they were brought to the laboratory in polythene bags for physic-chemical analysis Fruit size The size of fruit was measured in terms of length and diameter. The length and diameter of ten randomly selected fruits per vine were measured at the time of harvest with the help of a Digimatic caliper (Mitutoyo, Japan). The average fruit length and diameter were calculated and expressed in mm Fruit weight The weight of ten fruits selected for recording fruit size was taken on a top pan balance and the average weight was expressed in gram per fruit (g/fruit) Fruit firmness At the time of harvesting, the firmness of fruit was taken with the help of a pressure tester ( Effegi penetrometer) which recorded the pressure necessary for the plunger to penetrate the peeled flesh of kiwifruit and expressed in term of kg/cm Total soluble solids (TSS) The TSS content was determined with Erma- hand refractrometer (0-32 o B). The refractrometer was calibrated with distilled water before use. The total soluble solids were expressed in o Brix Titrable acidity Twenty five gram of fruit pulp was thoroughly mixed with distilled water in an electric blender and the volume was made to 250 ml. The mixture was then 82

104 filtered through Whatman No. 1 filter paper and 50 ml of sample was then titrated against N/ 10 NaOH solution using phenolphthalein as an indicator till it gave pink coloured end point. The total titratable acidity was calculated in terms of citric acid on the basis of 1 ml of N/10 NaOH equivalent to gram of anhydrous citric acid and expressed as per cent citric acid in juice ( Ranganna, 1995). The remaining filtered solution was used for sugar estimation Total Sugars To the remaining 200 ml filtered stock solution (left from titratable acidity), 10 ml of 45 per cent saturated lead acetate was added, contents of flask were shaken and filtered. Ten ml of 22 per cent potassium oxalate was later added to precipitate the excess of lead and the contents were again filtered and volume was made to 250 ml. Out of this, 100 ml of filtrate was taken in 250 ml volumetric flask and 5 ml concentrated HCl was added to it and left over night for hydrolysis at room temperature. The excess of HCl was neutralized with saturated NaOH solution and final volume was made 250 ml with distilled water. The total sugar was then estimated by titrating a boiling mixture of 5 ml each of Fehling A and Fehling B against hydrolyzed solution using methylene blue as an indicator (Ranganna, 1995). The end point was indicated by the appearance of brick red colour. Total sugar content was expressed as percentage of fresh weight of fruit pulp Reducing sugars The remaining unhydrolyzed, deleaded and clarified solution obtained from the total sugar estimation was titrated against a boiling solution of 5 ml each of Fehling A and Fehling B using methylene blue as an indicator (Ranganna, 1995). Reducing sugars content was expressed as percentage of fresh pulp weight Non-reducing sugar The amount of non-reducing sugar was calculated by subtracting the reducing sugars from the total sugars and multiplying the difference by a standard factor i.e The results were expressed as per cent non-reducing sugars. 83

105 Ascorbic Acid The quantitative determination of ascorbic acid was done with the help of indophenols solution (2, 6 dichlorophenol indophenols dye). Indophenol dye solution was first standardized against standard ascorbic acid. The indophenols dye and metaphosphoric acid solution were prepared fresh for each set of experiment and standardized against standard ascorbic acid to calculate the dye factor (A O A C, 1980). Ten grams of fruit pulp was homogenized in 3 per cent metaphosphoric acid solution and volume was made up to 50 ml in volumetric flask. This solution was titrated against indophenols dye. The end point was determined by the appearance of rose pink colour which persisted for few seconds. The amount of ascorbic acid in milligram per hundred grams of fresh fruit pulp was calculated by using following formula: Ascorbic acid (mg/100g) = Dye factor x Titre reading x Volume made Weight of fruit taken x Volume taken for estimation x STATISTICAL ANALYSIS The statistical analysis of the data was carried out as per method described by Gomez and Gomez (1984). The significance of different treatment s effect was tested at 5 per cent level of significance as suggested by Cochran and Cox (1963). 84

106 Chapter-4 EXPERIMENTAL RESULTS The present investigations entitled Studies on water relations and deficit irrigation in kiwifruit ( Actinidia deliciosa Chev.) were undertaken in the Department of Fruit Science, Dr. Y. S. Parmar University of Horticulture and Forestry, Nauni-Solan, H.P. during the years 2011 and In this study, two experiments were executed to accomplish the whole programme of research work. In experiment I, different kiwifruit cultivars were evaluated for their water deficit tolerant potential, while in experiment- II, the effects of in situ moisture conservation and deficit irrigation on growth, water relations and yield of kiwifruit were examined. The results obtained during the course of investigations are presented experiment-wise under suitable headings: 4.1 EXPERIMENT-I. SCREENING OF WATER DEFICIT TOLERANT CULTIVAR(S) OF KIWIFRUIT FOR MID- HILL CONDITIONS OF H. P VEGETATIVE GROWTH OF KIWIFRUIT CULTIVARS IN RESPONSE TO WATER DEFICIT Shoot growth The data on the shoot growth of kiwifruit cultivars as influenced by water stress are presented in Table and Fig It is evident from the data (Table 4.1.1) that shoot growth was influenced significantly by different irrigation levels during both the years of study. Shoot growth decreased with the imposing of soil moisture tension by applying irrigation at 60 per cent of field capacity in comparison to control (irrigation at 80 % FC). During the year 2011, the average shoot growth of different cultivars was reduced from cm under irrigation at 80 per cent of field capacity to cm under irrigation at 60 per cent of field capacity. In 2012, shoot growth decreased to cm under water stress treatment from 285.5cm in control. The pooled data also revealed that the shoot growth decreased significantly with deficit irrigation in comparison to control.

107 It is evident from the perusal of the data presented in Table that the cultivars showed significant variations in shoot growth under two irrigation regimes during both the years of study. The maximum shoot growth was recorded in cultivar Allison ( and cm in 2011 and 2012, respectively), which was significantly higher than the remaining cultivars. The shoot growth was observed significantly lowest (271.0 and cm in 2011 and 2012, respectively) in cultivar Monty. Similarly, the pooled data revealed that the shoot growth was significantly higher in cultivar Allison compared to the remaining cultivars, and it was observed the least in cultivar Monty. It is revealed from the Fig that over the two years, the average decrease in shoot growth as induced by deficit irrigation (irrigation at 60% FC) was higher in cultivar Hayward (15.5 % over control), while the decrease in shoot growth was the least in cultivar Bruno (2.28 % at 60% FC over 80 % FC) followed by the cultivar Allison. The interaction effect of cultivars and irrigation levels on shoot growth was also significant. The cultivar Hayward exhibited significantly higher shoot growth when irrigated at 80 per cent of field capacity (295.1 and cm during 2011 and 2012, respectively) than all other cultivars irrespective of irrigation treatments. However, the shoot growth was significantly lowest (250.1 and cm during 2011 and 2012, respectively) in the cultivar Hayward when irrigated at 60 per cent of field capacity, among all other treatment combinations Internode length The data pertaining to the length of internodes of kiwifruit cultivars as influenced by irrigation treatments have been presented in Table and Fig It is evident from the data (Table 4.1.2) that the length of internodes was influenced significantly by different irrigation levels during both the years of study. Irrigation applied at 60 per cent of field capacity decreased the length of internodes significantly in comparison to control (irrigation at 80 % FC). During the year 2011, the average length of internodes of different cultivars was reduced from 8.13 cm in vines irrigated at 80 per cent of field capacity to 7.95 cm in those 86

108 under irrigated at 60 per cent of field capacity. In the year 2012, the length of internodes decreased to 7.32 cm under water stress treatment from 8.10 cm in control. The pooled data also revealed that the length of internodes decreased significantly with deficit irrigation in comparison to control. It is evident from the perusal of the data presented in Table that the cultivars showed significant variations in the length of internodes under two irrigation regimes, during both the years of study. The maximum length of internodes (10.43 and 8.91 cm in 2011 and 2012, respectively) was recorded in cultivar Hayward, which was significantly higher than the remaining cultivars. However, the internodes length was observed significantly lowest (6.69 and 6.66 cm in 2011 and 2012, respectively) in cultivar Monty. Similarly, pooled data revealed that the length of internodes was registered significantly higher in cultivar Hayward compared to the other cultivars, and the least in cultivar Monty. The data depicted in Fig revealed that during the two years, the relative reduction in the internodes length due to deficit irrigation was more in the cultivar Hayward (16.94 % over control), while the reduction in the length of internodes was the least in cultivar Bruno (1.08 % over control), followed by the cultivar Allison. The interaction effect of cultivars and irrigation levels on the length of internodes was also significant. The vines of cultivar Hayward had significantly higher intermodal length when irrigated at 80 per cent of field capacity (10.57 and cm during 2011 and 2012, respectively) than all other cultivars, irrespective of irrigation treatments. However, the length of internodes was significantly lowest (6.59 and 6.60 cm during 2011 and 2012, respectively) in the cultivar Monty when irrigated at 60 per cent of field capacity, among all other treatment combinations Leaf area The data on the leaf area of kiwifruit cultivars as affected by different irrigation levels are presented in Table and Fig It is evident from the perusal of data (Table 4.1.3) that the influence of different irrigation levels on the average leaf area was significant, during both the 87

109 years of study. It was observed that the leaf area decreased significantly by applying irrigation at 60 per cent of field capacity compared with the irrigation when applied at 80 per cent of field capacity (control). During the year 2011, the average leaf area of different cultivars was decreased from cm 2 in vines irrigated at 80 per cent of field capacity to cm 2 in those irrigated at 60 per cent of field capacity. In the year 2012, again the leaf area decreased significantly to cm 2 under deficit irrigation treatment from cm 2 in control. The pooled data also revealed that the leaf area decreased significantly with deficit irrigation in comparison to control. The data presented in Table revealed that the cultivars showed significant variations in leaf area under two water regimes during both the years of study. During the year 2011, significantly largest leaves with an average area of cm 2 were obtained from the cultivar Hayward, whereas the smallest leaves were found in cultivar Monty (153.4 cm 2 ). During the year 2012, the leaf area was again found significantly largest in cultivar Hayward (156.2 cm 2 ) and significantly smallest in cultivar Monty (152.4 cm 2 ). The pooled data further revealed that the average leaf area was significantly largest in cultivar Hayward (157.0 cm 2 ) and significantly smallest cultivar Monty (152.9 cm 2 ). It is revealed from the Figure that the reduction in the leaf area due to deficit irrigation treatment (irrigation at 60% FC) was higher in cultivar Bruno (2.48 %) followed by Allison (2.01%), while the per cent reduction in leaf area as induced by deficit irrigation was lower in cultivar Hayward (1.22 %). The interaction effect of cultivars and irrigation levels on leaf thickness was also significant. The vines of cultivar Monty under deficit irrigation regime (irrigated at 60 % FC) produced significantly thickest leaves (0.446 and mm during 2011 and 2012, respectively), which in this respect were statistically at par with the cultivar Abbott during the year However, the leaves from the cultivar Bruno under control (irrigated at 80% FC) were least in thickness (0.394 and mm during 2011 and 2012, respectively) in comparison to all other treatment combinations, except the same cultivar under deficit irrigation during the year

110 Table Effect of different irrigation levels on shoot growth (cm) of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC (Control) 60 % FC (WS)* 80 % FC (Control) 60 % FC (WS) 80 % FC (Control) 60 % FC (WS) Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C) Table Effect of different irrigation levels on length of internodes (cm) of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC (Control) 60 % FC (WS) 80 % FC (Control) 60 % FC (WS) 80 % FC (Control) 60 % FC (WS) Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C) *WS- Water stress 89

111 Table Effect of different irrigation levels on leaf area (cm 2 ) of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 80 % FC 60 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C) Table Effect of different irrigation levels on leaf thickness (mm) of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 80 % FC 60 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C)

112 Reduction in shoot growth (%) Cultivars Allison Hayward Abbott Monty Bruno Figure Per cent reduction in shoot growth of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC (pooled) Reduction in length of internodes (%) Cultivars Allison Hayward Abbott Monty Bruno Figure Per cent reduction in length of internodes of different kiwifruit cultivarsat irrigation at 60 per cent FC over 80 per cent FC (pooled)

113 Leaf thickness The data on the leaf thickness of kiwifruit cultivars as influenced by water stress have been presented in Table and Figure It is evident from the data (Table 4.1.4) that leaf thickness was influenced significantly by different irrigation levels during both the years of study. The leaf thickness of kiwifruit cultivars was invariably increased by deficit irrigation (irrigation applied at 60 % FC) when compared with control (irrigation at 80 % FC). During the year 2011, the average leaf thickness of different cultivars was significantly increased from mm when irrigation was applied at 80 per cent of field capacity to mm under deficit irrigation (at 60% FC). In the year 2012, the average leaf thickness significantly increased from mm in control to mm under deficit irrigation treatment. The pooled data also revealed that the leaf thickness increased significantly with deficit irrigation in comparison to control. It is evident from the perusal of the data presented in Table that the cultivars showed significant variations in leaf thickness under two different water regimes during both the years of study. The maximum leaf thickness was recorded in cultivar Monty (0.443 and mm in 2011 and 2012, respectively), which was significantly higher than the remaining cultivars. During the year 2011, the leaf thickness was observed significantly lowest (0.394 mm) in cultivar Bruno. However during 2012, the least value of leaf thickness (0.421 mm) was noticed jointly in cultivars Bruno and Hayward, which was however, statistically at par with the cultivar Allison. The pooled data revealed that leaf thickness was registered significantly higher in cultivars Monty (0.448 mm) compared to the remaining four cultivars. The average value of leaf thickness was observed significantly least ( mm) in cultivar Bruno. It is revealed from the Fig that deficit irrigation caused higher increase in leaf thickness (2.85 %) over the control in cultivar Bruno, whereas the increase in leaf thickness was marginal in cultivar Hayward (0.38 % at 60 % FC over the control). 91

114 The interaction effect of cultivars and irrigation levels on leaf thickness was also significant. The vines of cultivar Monty under deficit irrigation regime (irrigated at 60 % FC) produced significantly thickest leaves (0.446 and mm during 2011 and 2012, respectively), which in this respect were statistically at par with the cultivar Abbott during the year However, the leaves from the cultivar Bruno under control ( irrigated at 80% FC) were least in thickness (0.394 and mm during 2011 and 2012, respectively) in comparison to all other treatment combinations, except the same cultivar under deficit irrigation during the year Leaf yellowing The observations on the leaf yellowing of kiwifruit cultivars as affected by irrigation regimes are given in Table and further depicted in Figure It is evident from the perusal of data in Table that the leaf yellowing was influenced significantly by different irrigation treatments during both the years of study. The yellowing of leaves was increased by deficit irrigation over the control from 20.0 per cent to 29.6 per cent and 20.8 per cent to 30.3 per cent in the years 2011 and 2012, respectively. The pooled data also revealed that the leaf yellowing increased significantly following deficit irrigation (29.9%) in comparison to control (20.4%). It is evident from the perusal of the data presented in Table that the leaf yellowing of different cultivars under two water regimes was significantly variable in both the years of study. The leaf yellowing was observed significantly higher in cultivar Hayward (36.8 and 37.1 % in 2011 and 2012, respectively) in comparison to all other cultivars. However, the leaf yellowing was observed significantly lowest (15.9 and 16.6 % in 2011 and 2012, respectively) in cultivar Abbott. Similarly, pooled data revealed that the leaf yellowing was noticed significantly higher in cultivar Hayward in comparison to the other cultivars and significantly least in cultivar Abbott. It is revealed from the Fig that the increase in the leaf yellowing by the deficit irrigation treatment was more cultivar Hayward (55.8 % increase with 92

115 Reduction in leaf area (%) Cultivars Allison Hayward Abbott Monty Bruno Figure Per cent reduction in Leaf area of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC (pooled) Leaf thickness (%) Allison Hayward Abbott Monty Bruno Cultivars Figure Per cent increase in Leaf thickness (mm) of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC (pooled)

116 Table Effect of different irrigation levels on leaf yellowing (%) of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 80 % FC 60 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C) Table Effect of different irrigation levels on bloom intensity (%) of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 80 % FC 60 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C)

117 Table Effect of different irrigation levels on fruit set (%) of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 80 % FC 60 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C) Table Effect of different irrigation levels on fruit retention (%) of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 80 % FC 60 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C)

118 Leaf yellowing (%) Allison Hayward Abbott Monty Bruno Cultivars Figure Per cent increase in leaf yellowing of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC (pooled) Reduction in bloom intensity (%) Cultivars Allison Hayward Abbott Monty Bruno Figure Per cent reduction in bloom intensity (%) of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC (pooled)

119 deficit irrigation over control), while it was registered the least in cultivar Bruno (34.4 % increase with deficit irrigation over control). The interaction effect of cultivars and irrigation levels on leaf yellowing was also significant. The extent of leaf yellowing was recorded significantly higher in cultivar Hayward when subjected to deficit irrigation (45.5 and 45.2 % in 2011 and 2012, respectively) in comparison to all other treatment combinations. The leaf yellowing was observed significantly lowest in cultivar Abbott (12.5 and 13.0 % in 2011 and 2012, respectively) when irrigated at 80 per cent of field capacity among all the treatment combinations. Similarly, pooled data revealed that the leaf yellowing was significantly higher in cultivar Hayward (44.3%) under deficit irrigation condition than all other cultivars irrespective of irrigation treatments and significantly least in cultivar Abbott (12.8%) under regular irrigation regime FLOWERING AND FRUITING Bloom intensity The observations on the influence of water deficit on bloom intensity of different kiwifruit cultivars are shown in Table and illustrated Fig It is evident from the data (Table ) that bloom intensity was influenced significantly by different irrigation levels during both the years of study. The study clearly demonstrated that the deficit irrigation treatment significantly decreased the bloom intensity of vines in comparison to the vines irrigated at 80 per cent of field capacity (control). During the year 2011, the average bloom intensity of different cultivars was reduced from 0.66 per cent under control (irrigation at 80 % FC) to 0.63 per cent under deficit irrigation at (irrigation at 60 % FC). In 2012, bloom intensity decreased from 0.64 per cent in control to 0.62 per cent under deficit irrigation. The pooled data also revealed that the bloom intensity decreased significantly by deficit irrigation in comparison to control. It is evident from the perusal of the data presented in Table that the cultivars showed significant variations in bloom intensity under two water regimes during both the years of study. The maximum bloom intensity (0.68 and 95

120 0.66 % in 2011 and 2012, respectively) was recorded in cultivar Bruno, which was significantly higher than the remaining cultivars except, the cultivar Allison during the year The bloom intensity was observed significantly lowest (0.60 and 0.58 % in 2011 and 2012, respectively) in cultivar Hayward, among all other cultivars. Similarly, pooled data revealed that bloom intensity was registered significantly higher in cultivar Bruno compared to the other cultivars, and the least in cultivar Hayward. The reduction in per cent bloom intensity was more pronounced in cv. Hayward (8.01 %) when vines were supplied with deficit water (irrigation at 60% FC) in comparison to control, while the reduction in bloom intensity under water deficit condition was the least in cultivar Bruno (2.04 % at 60 % FC over 80 % FC) followed by the cv. Allison (Fig ). The interaction effect of cultivars and irrigation levels on bloom intensity was also significant. Significantly higher bloom intensity was observed in cultivar Bruno (0.68 and 0.67 per cent during 2011 and 2012 respectively) than all other cultivars irrespective of irrigation regimes except Monty under control. However, the bloom intensity was significantly lowest (0.57 and 0.56 % during 2011 and 2012 respectively) in the cultivar Hayward when irrigated at 60 per cent of field capacity, among all other treatment combinations. Pooled analyzed data also revealed that the bloom intensity was significantly highest (0.68%) in the cultivar Bruno under regular irrigation regime and the lowest (0.57%) in cultivar Hayward under deficit irrigation condition Fruit set The data on the fruit set of kiwifruit cultivars under different irrigation regimes are presented in Table and Figure It is evident from the data (Table ) that fruit set was influenced significantly by different irrigation levels during both the years of study. Fruit set decreased with the decrease in the supply of irrigation water (Irrigation at 60 % FC) compared with control ( irrigation at 80% FC). During the year 2011, the average fruit set was reduced from 85.6 per cent under control to 77.8 per cent under deficit irrigation. In the year 2012, fruit set was significantly lower (

121 %) under water stress treatment than control (85.3 %). The pooled data also revealed that the fruit set decreased significantly with deficit irrigation (77.8%) in comparison to control (85.4%). It is evident from the perusal of the data presented in Table that the cultivars showed significant variations in fruit set under different water regimes, during both the years of study. During the year 2011, the maximum fruit set (83.6 %) was observed in cultivar Allison, which was however, statistically at par with the cultivar Bruno. During the following year, the fruit set was recorded significantly higher in cultivar Bruno (83. 2 %) in comparison to the remaining cultivars and in this respect, the next superior cultivar was Allison. However, the fruit set was recorded significantly lowest (78.9 and 78.9 % in 2011 and 2012, respectively) in cultivar Hayward among all other cultivars during both the years. The pooled data revealed that fruit set was significantly higher in cultivar Allison as compared to all other cultivars except, Bruno, and significantly least in cultivar Hayward. It is revealed from the Figure that the decrease in the per cent fruit set due to deficit irrigation was highest in cultivar Hayward (14.80 %), and the least in cultivar Bruno (4.87 % at 60 % FC over 80 % FC), followed by the cultivar Allison. The interaction effect of cultivars and irrigation levels on fruit set was also significant. The fruit set was observed significantly higher in the cultivar Allison (86.7 %) when irrigated at 80 per cent of field capacity in the year 2011, while during the following year, the fruit set was found highest jointly (85.6 %) in cultivars Abbott and Allison under control than the remaining cultivars irrespective of irrigation treatments. The fruit set was noticed however, significantly lowest ( 72.6 and 72.6 % during 2011 and 2012, respectively) in cultivar Hayward when irrigated at 60 per cent of field capacity, among all other treatment combinations. Pooled data also revealed that fruit set was significantly highest in cultivar Allison (86.1 %) when irrigated at 80 per cent of field capacity and significantly lowest in cultivar Hayward (78.9 %) when irrigated at 60 per cent of field capacity among all the treatment combinations. 97

122 Fruit retention The data on fruit retention of kiwifruit cultivars as influenced by different irrigation regimes have presented in Table and Figure It is revealed from the perusal of the data in Table that the fruit retention was influenced significantly by different irrigation levels during both the years of study. Application of irrigation at 60 per cent of field capacity decreased the fruit retention in comparison to the irrigation applied at 80 per cent of field capacity (control). During the year 2011, the average fruit retention of kiwifruit cultivars was reduced from 80.0 per cent under control to 62.7 per cent under deficit irrigation. Likewise in 2012, fruit retention was decreased significantly from 78.8 per cent under control to 61.2 per cent water stress treatment. The pooled data also revealed that the fruit retention decreased significantly with deficit irrigation in comparison to control. The data in Table revealed that fruit retention of kiwifruit cultivars was significantly influenced by the irrigation treatments during both the years. Significantly higher fruit retention was recorded in cultivar Allison (79.5 and 78.0 % in 2011 and 2012, respectively) in comparison to all other cultivars. However, fruit retention was observed significantly lower in the cultivar Hayward (68.2 and 53.3 % in 2011 and 2012, respectively) compared to the remaining cultivars except, Monty in the year The perusal of pooled data also revealed significantly higher fruit retention in cultivar Allison (78.7 %) than all other cultivars. However, fruit retention was observed significantly lowest in cultivar Hayward (67.5 %). The Figure revealed that the per cent fruit retention was decreased more in cultivar Hayward by deficit irrigation treatment (32.8% over the control), while the decrease in fruit retention was the least in cultivar Bruno ( 10.7 %), followed by the cultivar Allison. The interaction effect of cultivars and irrigation levels on fruit retention was also significant. The cultivar Allison exhibited significantly higher fruit retention (85.5 and 84.4 % in 2011 and 2012, respectively) when irrigated at 80 per cent of field capacity than all other cultivars, irrespective of irrigation 98

123 Cultivars Reduction in fruit set (%) Allison Hayward Abbott Monty Bruno Figure Per cent reduction in fruit set (%) of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC (pooled) 0 Cultivars Allison Hayward Abbott Monty Bruno Reduction in fruit retention (%) Figure Per cent reduction in fruit retention of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC (pooled)

124 treatments. However, fruit retention was observed significantly lowest (56.2 and 53.3 % in 2011 and 2012, respectively) in the cultivar Hayward when irrigated at 60 per cent of field capacity, among all other treatment combinations Fruit yield Total fruit yield The data on the influence of irrigation treatments on the total fruit yield of kiwifruit cultivars are presented in Table and Figure It is apparent from the data (Table 4.1.9) that the fruit yield of kiwifruit was influenced significantly by different irrigation levels during both the years of study. The total fruit yield decreased significantly from 57.6 kg/vine in control to 51.3 kg/vine under deficit irrigation in the year 2011 and from 56.4 kg/vine in control to 49.7 kg/vine under deficit irrigation in the year The pooled data also revealed that the total fruit yield decreased significantly following deficit irrigation (50.5 kg/vine) in comparison to control (57.0 kg/vine). The data presented in Table revealed that the total fruit yield of different cultivars under two irrigation regimes was influenced significantly during both the years of study. The maximum total fruit yield was observed in cultivar Allison (65.0 and 64.2 kg/vine in 2011 and 2012, respectively), which was however, statistically at par with cultivar Bruno (64.5 kg/vine) during the year 2011 but significantly higher than the remaining cultivars in the year Pooled data however, clearly indicate that total fruit yield was significantly higher in cultivar Allison than all other cultivars and significantly least in cultivar Monty. It is revealed from the Figure that the per cent decrease in total fruit yield due to water stress imposed by deficit irrigation was higher in cultivar Hayward (17.5 %), while the decrease in total fruit yield due to water stress was the least in cultivar Bruno (1.7 %) over the control. The interaction effect of cultivars and irrigation levels on total fruit yield was also significant. The cultivar Allison registered significantly higher total fruit yield under regular irrigation treatment (67.0 & 66.0 kg/vine during 2011 and 99

125 2012, respectively) in comparison to all other treatment combinations. However, the total fruit yield was observed significantly lower in cultivar Hayward (38.5 and 35.4 kg/vine during the year 2011 and 2012, respectively) when irrigated at 60 per cent of field capacity than all other treatment combinations. Similarly, pooled data revealed that total fruit yield was significantly higher in cultivar Allison (66.5 kg/vine) under regular irrigation regime than all other cultivars irrespective of irrigation treatments and significantly least in cultivar Hayward (36.9 kg/vine) under deficit irrigation condition Graded fruit yield A Grade fruit yield The data on the graded fruit yield of kiwifruit cultivars as influenced by two different irrigation regimes are shown in Tables , and and depicted in Figure Two irrigation levels exerted a significant influence on the production of A grade fruit during course of study. It was observed that the A grade fruit yield decreased significantly when kiwifruit vines were subjected to water deficit condition by applying lesser than regular irrigation. During the year 2011, the average A grade fruit yield of different cultivars was reduced significantly from 40.6 per cent of total fruit yield per vine under standard irrigation regime to 33.5 per cent under deficit irrigation (Table ). In the year 2012, A grade fruit yield decreased from 40.5 per cent of total fruit yield per vine in control to 32.9 per cent under water stress treatment (Table ). The pooled data also revealed that the A grade fruit yield decreased significantly with deficit irrigation in comparison to control (Table ). It is evident from the perusal of the data presented in Tables , , that the cultivars showed significant variations in respect of production of A grade fruit under two water regimes during both the years of study. During the year 2011, the A grade fruit yield was significantly higher in cultivar Bruno (56.2 %) which was followed by cultivar Hayward (53.1 %). However, A grade fruit yield was observed significantly least in cultivar Monty (20.5 %) compared with all other cultivars. During the year 2012, the A grade 100

126 Cultivars Reduction in total fruit yield (%) Allison Hayward Abbott Monty Bruno Figure Per cent reduction in total fruit yield of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC (pooled) Cultivars Reduction in A grade fruit yield (%) Allison Hayward Abbott Monty Bruno Figure Per cent reduction in A grade fruit yield of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC (pooled)

127 fruit yield was observed significantly higher in cultivar Bruno (56.1 %) comparison to the remaining cultivars, while proportionate yield of A grade fruit was significantly least in cultivar Monty (20.8 %). Similarly, pooled data revealed that A grade fruit yield was registered significantly higher in cultivar Bruno (56.1 %) than the remaining four cultivars, and significantly lowest in cultivar Monty (20.6 %). The per cent decrease in the production of A grade fruit as a result of water stress imposed by deficit irrigation (Fig ) was more pronounced in cultivar Hayward (27.5 % decrease over control), while the reduction in A grade fruit yield by deficit irrigation was the least in cultivar Bruno (3.5 %). The interaction effect of cultivars and irrigation levels on A grade fruit yield was also significant (Tab les & ). During both the years, significantly higher A grade fruit yield (61.4 % and 61.0 % in 2011 and 2012, respectively) was observed in the cultivar Hayward when irrigated at 80 per cent of field capacity over all other treatment combinations. However, the A grade fruit yield was significantly lowest (18.2 % and 18.3 % in 2011 and 2012, respectively) in the cultivar Monty when irrigated at 60 per cent of field capacity, among all other treatment combinations. Pooled data also showed similar results on this aspect (Table ) B Grade fruit yield The data on the production of B grade fruits of different kiwifruit cultivars as affected by two irrigation regimes are presented in Tables , , and Figure The yield of B grade fruits decreased significantly when kiwifruit vines were subjected to water deficit condition by applying lesser than normal irrigation. During the year 2011, the average B grade fruit yield of different cultivars decreased significantly from 27.4 per cent under irrigation at 80 per cent of field capacity to 22.4 per cent under irrigation at 60 per cent of field capacity (Table ). Similarly, B grade fruit yield decreased significantly from 27.2 per cent in control to 21.9 per cent of total yield under water stress treatment in 2012 (Table ). The pooled data (Table ) also revealed that the 101

128 B grade fruit yield decreased significantly following deficit irrigation (22.1 %) in comparison to control (27.3 %). The data presented in Tables , and revealed that the production of B grade fruit varied significantly among the different kiwifruit cultivars raised under two irrigation treatments during both the years of study. The B grade fruit yield was significantly higher in cultivar Allison (35.4 and 34.8 per cent of total yield/vine in 2011 and 2012, respectively) than all other cultivars. However, the B grade fruit yield was significantly lowest in cultivar Hayward (7.3 and 7.2 per cent of total yield/vine in 2011 and 2012, respectively). Similarly, pooled data (Table ) revealed that B grade fruit yield was significantly higher in cultivar Allison (35.1 %) than all other cultivars and significantly least in cultivar Hayward (7.3 %). It is apparent from the Figure that the deficit irrigation caused higher reduction in the production of B grade fruits in cultivar Hayward (58.5 % reduction over control), while the reduction in B grade fruit yield due to deficit irrigation was the least in cultivar Bruno (2.6 % ). The interaction effect of cultivars and irrigation levels on B grade fruit yield revealed significantly highest B grade fruit yield in the cultivar Allison raised under regular irrigation ( 37.5 %) during both the years among all the treatment combinations. However, the B grade fruit yield was observed significantly lowest in cultivar Hayward (4.3 and 4.2 % during the year 2011 and 2012, respectively) when irrigated at 60 per cent of field capacity. Similarly, pooled data revealed that B grade fruit yield was recorded significantly higher in cultivar Allison (37.5 %) under regular irrigation regime than all other cultivars irrespective of irrigation treatments and significantly least in cultivar Hayward (4.3 %) under deficit irrigation condition C Grade fruit yield The data on the influence of irrigation treatments on the production of C grade fruits of different kiwifruit cultivars have been shown in Tables , , and depicted in Figure

129 Cultivars Reduction in B grade fruit yield (%) Allison Hayward Abbott Monty Bruno Figure Per cent reduction in B grade fruit yield of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC C grade fruit yield (%) Allison Hayward Abbott Monty Bruno Cultivars Figure Per cent increase in C grade fruit yield of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC

130 Table Effect of different irrigation levels on fruit yield (Kg/vine) of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 80 % FC 60 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C) Table Effect of different irrigation levels on graded yield (% of total fruit yield) of kiwifruit cultivars during 2011 Cultivars Graded yield (%) A B C D Irrigation treatments Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 %FC Mean 80 % FC 60 %FC Mean 80 % FC 60 %FC Mean 80 % FC 60 %FC Mean Allison Hayward Abbott Monty Bruno Mean CD 0.05 I C I X C

131 Table Effect of different irrigation levels on graded yield (% of total fruit yield) of kiwifruit cultivars during 2012 Cultivars Graded yield (%) A B C D Irrigation treatments 80 % FC 60 %FC Mean 80 % FC 60 %FC Mean 80 % FC 60 %FC Mean 80 % FC 60 %FC Mean Allison Hayward Abbott Monty Bruno Mean CD 0.05 I C I X C Table Effect of different irrigation levels on graded yield (%) of kiwifruit cultivars during (pooled) Cultivars Graded yield (% ) A B C D Irrigation treatments 80 % FC 60 %FC Mean 80 % FC 60 %FC Mean 80 % FC 60 %FC Mean 80 % FC 60 %FC Mean Allison Hayward Abbott Monty Bruno Mean CD 0.05 I C I X C

132 The irrigation levels exerted a significant influence on the production of C grade fruits during course of study. It was observed that the C grade fruit yield increased significantly when kiwifruit vines were subjected to deficit irrigation treatment. During the year 2011, the average C grade fruit yield of different cultivars increased from 23.7 per cent in vines irrigated at 80 per cent of field capacity to 29.9 per cent in those irrigated at 60 per cent of field capacity (Table ). In the year 2012, C grade fruit yield increased from 23.7 per cent in control to 29.8 per cent under deficit irrigation treatment (Table ). The pooled data also revealed that the C grade fruit yield increased significantly from 23.7 per cent in control to 29.9 per cent under deficit irrigation (Table ). The cultivars exhibited significant variations in C grade fruit yield under two water regimes during both the years of study. The maximum C grade fruit yield was recorded in cultivar Monty (45.9 and 45.7 % in 2011 and 2012, respectively), which was significantly higher than the remaining cultivars. The C grade fruit yield was observed significantly lowest ( 9.5 and 9.5 % in 2011 and 2012, respectively) in cultivar Bruno. Similarly, pooled data (Table ) revealed that the production of C grade fruits was significantly higher in cultivars Monty (45.8 % of total fruit yield/vine) compared to the remaining four cultivars and significantly least (9.5 %) in cultivar Bruno. It is revealed from the Fig that deficit irrigation caused higher per cent increase in the production of C grade fruit in cultivar Hayward (78.3 %) over the control, while the increase in C grade fruit yield due to deficit irrigation was the least in cultivar Bruno (8.2 %). The interaction effect of cultivars and irrigation levels on C grade fruit yield was also significant, in this study. The maximum percentage of C grade fruits were recorded in cultivar Monty under deficit irrigation (48.5 and 49.0 % during 2011 and 2012 respectively), which was significantly higher than all other cultivars irrespective of irrigation treatments. However, the vines of cultivar Bruno produced significantly lower percentage of C grade fruit (9.2 and 9.0 % during 2011 and 2012 respectively) when irrigated at 80 per cent of field capacity than the remaining treatment combinations. Pooled analyzed data also revealed 105

133 that C grade fruit yield was observed significantly highest in cultivar Monty under deficit irrigation (48.8 %), while it was found significantly lowest in cultivar Bruno under control (9.1 %), among all the treatment combinations D Grade fruit yield The data on the yield of D grade fruits of different kiwifruit cultivars maintained under two irrigation regimes have been displayed in Tables , and and Figure The irrigation levels exerted a significant influence on the yield of D grade fruit during course of study. It was observed that the yield of D grade fruit was increased significantly by the deficit irrigation as compared to regular irrigation. During the year 2011, the average yield of D grade fruits of different cultivars increased significantly from 8.3 per cent in control to 14.2 per cent under deficit irrigation (Table ). In the year 2012, D grade fruit yield increased from 8.6 per cent in control to 15.4 per cent under deficit irrigation treatment (Table ). The pooled data also revealed that the yield of D grade fruit increased significantly with deficit irrigation in comparison to control (Table ). The data presented in Tables , and revealed that the production of D grade fruit varied significantly among the different kiwifruit cultivars in response to irrigation treatments during both the years of study. During the year 2011, the yield of D grade fruit was significantly higher in cultivar Hayward (14.8 %) than the remaining four cultivars. However, D grade fruit yield was observed significantly least in cultivar Bruno (5.6 %) among all other cultivars. During the year 2012, the D grade fruit yield was again found significantly higher in cultivar Hayward (17.1 %) than the remaining four cultivars whereas, the production of D grade fruits was the least in cultivar Bruno (5.8 %). Similarly, pooled data revealed that the D grade fruit yield was observed significantly higher in cultivar Hayward (15.9 %) compared to all the other cultivars whereas, the least was observed in cultivar Bruno (5.7 %). The increase in the production of D grade fruits due to deficit irrigation (Fig ) was more pronounced in cultivar Hayward (82.7 % increase over the 106

134 D grade fruit yield (%) Allison Hayward Abbott Monty Bruno Cultivars Figure Per cent increase in D grade fruit yield of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC

135 control), while the increase in the D grade fruit yield was the least in cultivar Bruno (42.6 %) following deficit irrigation. The interaction effect of cultivars and irrigation levels on the yield of D grade fruits was also significant, during the study. In the year 2011, the production of D grade fruit was significantly higher in the cultivar Hayward (18.5 %) which was statistically at par with cultivar Abbott (18.2 %) under deficit irrigation. During 2012, the highest D grade fruit yield was also observed in the cultivar Hayward (22.6%) when irrigated at 60 per cent of field capacity in comparison to all other cultivars regardless of irrigation regimes. However, the D grade fruit yield was significantly lowest (4.6 % and 4.8 % in 2011 and 2012, respectively) in the cultivar Bruno when irrigated at 80 per cent of field capacity, among all other treatment combinations. Pooled data (Table ) also showed similar results, on this aspect SOIL MOISTURE CONTENT Soil moisture content of kiwifruit cultivars in response to irrigation treatments The soil moisture content fluctuated greatly during the period of growing season, with irrigation levels, soil depth and cultivars (Figures , , and ; Appendices 1, 2). It is evident from the data that the soil moisture content varied greatly during different periods of growing seasons from 15.3 to 20.1 per cent and 15.2 to 19.7 per cent during 2011(Figures a & b) and 2012 (4.1.15a & b), respectively under the vines irrigated at 60 per cent FC. Whereas, under standard irrigation practice (irrigation at 80 % FC), the soil moisture content varied from 16.9 to 20.9 per cent in the year 2011 (Figures a & b) and from 16.8 to 20.8 per cent in 2012(Figures a & b). Although, periodic fluctuation in soil moisture content varied among the cultivars however, the average soil moisture content under different cultivars (Appendices 1, 2) was found higher during the months of June-August and lower during the months of March-May and September-October irrespective of irrigation treatments and soil depth (Figures 16a-d & 17a-d). 107

136 Soil moisture (%)20 Fig (a) Months % FC % FC 0 Months Soil moisture (%)30 Fig (b) 80%FC 60% FC Figure Average soil moisture content (%) of five cultivars of kiwifruit under two irrigation levels at 30 cm soil depth (a) and at 60 cm soil depth (b) during the year 2011 Soil moisture (%) % FC 5 60% FC 0 Soil moisture (%)20 80% FC 60 % FC Months Months Fig (a) Fig (b) Figure Average soil moisture content (%) of five cultivars of kiwifruit under two irrigation levels at 30 cm soil depth (a) and at 60 cm soil depth (b) during the year 2012 Soil moisture content (%) Allison Hayward Abbott Monty Bruno Months Figure a. Periodic soil moisture content at 30 cm soil depth during 2011 as affected by irrigation treatments (80 %FC) in kiwifruit cultivars 108

137 Soil moisture content (%) Allison Hayward Abbott Monty Bruno Months Figure b. Periodic soil moisture content at 30 cm soil depth during 2011 as affected by irrigation treatments (60% FC) in kiwifruit cultivars 25 Soil moisture content (%) Allison Hayward Abbott Monty Bruno Months Figure c. Periodic soil moisture content at 60 cm soil depth during 2011 as affected by irrigation treatments (80% FC) in kiwifruit cultivars 109

138 25 Soil moisture content (%) Allison Hayward Abbott Monty Bruno Months Figure d. Periodic soil moisture content at 60 cm soil depth during 2011 as affected by irrigation treatments (60% FC) in kiwifruit cultivars 25 Soil moisture content (%) Allison Hayward Abbott Monty Bruno Months Figure a. Periodic soil moisture content at 30 cm soil depth during 2012 as affected by irrigation treatments (80 %FC) in kiwifruit cultivars 110

139 25 Soil moisture content (%) Allison Hayward Abbott Monty Bruno Months Figure b. Periodic soil moisture content at 30 cm soil depth during 2012 as affected by irrigation treatments (60 %FC) in kiwifruit cultivars 25 Soil moisture content (%) Allison Hayward Abbott Monty Bruno Months Figure 17 c. Periodic soil moisture content at 60 cm soil depth during 2012 as affected by irrigation treatments (80 %FC) in kiwifruit cultivars 111

140 25 Soil moisture content (%) Allison Hayward Abbott Monty Bruno Months Figure d. Periodic soil moisture content at 60 cm soil depth during 2012 as affected by irrigation treatments (60 %FC) in kiwifruit cultivars During the year 2011, soil moisture content at the 30 cm depth of soil profile was found highest in cultivar Abbott in the month of March (19.8%) under irrigation at 80 per cent FC and its least value was observed in Abbott cultivar during the month of May (7.0%). During 2012, the higher soil moisture at 30 m soil depth was found in cultivar Allison (20 %) in the month of May under irrigation at 80 per cent FC and its least value was observed in Hayward (7.1%) under deficit irrigation treatment (Appendix-III). During the year 2011, the soil moisture content at 60 cm soil depth was found highest in cultivar Abbott during March under the vines irrigated at 80 per cent of FC and the lowest soil moisture level (11.3%) was noticed in c ultivar Hayward under deficit irrigation treatment during the month of September. During the year 2012, the highest soil moisture content was found in cultivar Allison (20.9%) during the month of May under vines irrigated at 80 per cent of FC, whereas its least value was observed in cultivar Hayward (10.8 %) during September under the vines irrigated at 60 per cent of FC (Appendix-III). During the growing period of 2011, the average soil moisture content at 30 cm of depth was recorded higher under cultivars Allison and Bruno irrespective of irrigation regime. At this depth, the lowest soil moisture contents 112

141 were noticed under the cultivar Monty (Figure 18 a). The soil moisture level at 60 cm depth was observed highest in cultivar Abbott under standard irrigation regime, whereas, its minimum value was recorded under the cultivar Hayward (16.0%) under deficit irrigation (Figure 1 8 b). Soil moisture level was recorded invariably higher under standard irrigation compare to deficit irrigation regime regardless of time (Appendix III), soil depth, and cultivars. During the year 2012, the higher soil moisture content at 30 cm depth was observed higher under the cultivar Bruno provided with standard irrigation, while its least value was recorded under cultivar Hayward given deficit irrigation (Figure 19 a). However, at the depth of 60 cm, the soil moisture content was found maximum in cultivar Abbott under standard irrigation regime and the minimum under the cultivar Hayward when given deficit irrigation (Figure 19 b). The moisture level was recorded higher under standard irrigation over the deficit irrigation regime regardless of cultivars. 20 IR 80 % FC IR 60 % FC A verage S oil M oistu re C on ten t (%) Allison H ayw ard Abbott M onty Bruno C ultivars Figure a. Average soil moisture content during 2011at 30 cm soil depth as affected by irrigation treatments in kiwifruit cultivars 113

142 2 0 IR 80 % FC IR 60 % FC A v e r a g e S o il M o istu r e C o n te n t (%) Allison H ayw ard Abbott M onty Bruno C u ltiv a r s Figure b. Average soil moisture content during 2011at 60 cm soil depth as affected by irrigation treatments in kiwifruit cultivars 2 0 IR 8 0 % F C IR 6 0 % F C 1 6 A v e r a g e S o il M o is tu r e C o n te n t (%) A lliso n H a y w a rd A b b o tt M o n ty B ru n o C u ltiv a r s Figure a. Average soil moisture content during 2012 at 30 cm soil depth as affected by irrigation treatments in kiwifruit cultivars 114

143 20 IR 80 % FC IR 60 % FC Average Soil M oisture Content (%) Allison Hayward Abbott M onty Bruno C ultivars Figure b. Average soil moisture content during 2012 at 60 cm soil depth as affected by irrigation treatments in kiwifruit cultivars Cultivars Reduction in soil moisture content (%) Allison Hayward Abbott Monty Bruno Figure Depletion of soil moisture content (%) due to deficit irrigation in comparison to standard irrigation regime under different Kiwifruit cultivars (average of 2011 & 2012) It is clear from Figure that the per cent decrease in soil moisture content as recorded under the deficit irrigation treatment over the control was more in cultivar Hayward (11.39 %), while it was observed the least in cultivar Bruno ( 4.55 %) followed by Allison (8.73%). 115

144 Frequency and number of irrigations The data pertaining to the frequency and number of irrigations applied at 80 per cent and 60 per cent FC are presented in Table and Table During the year 2011, the first irrigation was applied to all of the experimental vines on 15 th March (Table ). The interval between first and second irrigation was 7 and 10 days in the irrigation treatment given at 80 per cent and 60 per cent FC, respectively. The irrigation intervals in the month of April, May, June and July however, varied from 14 to 21 and 14 to 28 days under the irrigation treatments given at 80 per cent and 60 per cent FC, respectively. During 2012, the first irrigation was applied on 14 th March and the interval between first and second irrigation was 6 and 9 days under the irrigation treatments given at 80 per cent and 60 per cent FC, respectively (Table ). In the months of March and April, the irrigation intervals under the treatments applied at 80 per cent and 60 per cent FC varied from 6 to 14 and 9 to 19 days, respectively. Thereafter from May to July, irrigation intervals varied from 14 to 18 and 26 to 29 days, respectively under the irrigation treatments applied at 80 per cent and 60 per cent FC. In the month of August, intervals between subsequent irrigations increased to 17 and 41 days under irrigation treatments given at 80 per cent and 60 per cent FC, respectively. During the course of study in 2011 and 2012, in all the cultivars the total number of irrigations applied under irrigation treatments given at 80 per cent and 60 per cent FC were 16 and 10, respectively CANOPY TEMPERATURE The data on the average canopy temperature of kiwifruit vines under different irrigation treatments, recorded from the month May to August during 2011 and 2012 are presented in Table and Appendix IV. It is evident from the data (Table ) that the canopy temperature increased with the deficit irrigation treatment during both the years of study. During the year 2011, the average canopy temperature of different cultivars significantly increased from 27.6 O C under irrigation at 80 per cent of field capacity to 29.3 O C under irrigation at 60 per cent of field capacity. In the year 116

145 Table Dates on which irrigation was given to kiwifruit vines under different levels of irrigations (2011) Irrigation levels Irrigation at 80 % FC Irrigation at 60 % FC Date of irrigation Interval (days) Date of irrigation Interval (days) Table Dates on which irrigation was given to kiwifruit vines under different levels of irrigations (2012) Irrigation levels Irrigation at 80 % FC Irrigation at 60 % FC Date of irrigation Interval (days) Date of irrigation Interval (days)

146 2012, the average canopy temperature increased from 27.5 O C in control to 29.5 O C under deficit irrigation treatment. The pooled data also revealed that the canopy temperature increased significantly with deficit irrigation in comparison to control. It is evident from the perusal of the data presented in Table that the cultivars showed significant variations in canopy temperature under two different water regimes during both the years of study. During 2011, significantly higher canopy temperature was recorded in cultivar Hayward (28.9 O C) in comparison to the remaining cultivars except, Monty (28.8 O C), while during 2012, significantly highest temperature (29.0 O C) was observed in cultivar Hayward in comparison to the remaining cultivars, which was followed by cultivar Monty (28.8 O C). The canopy temperature was observed significantly lowest in cultivar Bruno (27.7 O C and 27.6 O C during 2011 and 2012, respectively) followed by Allison. The pooled data revealed that the canopy temperature was significantly higher in cultivar Hayward and lower in cultivars Bruno. The data depicted in Fig showed that, the per cent increase in canopy temperature due to deficit irrigation was highest in cultivar Hayward (8.63 %), and lowest in cultivar Bruno (5.58 %) followed by Allison (5.80 %). The interaction effect of cultivars and irrigation levels on canopy temperature was also significant. During the year 2011, the deficit irrigation treatment resulted in significantly higher canopy temperature in cultivar Hayward (30.0 O C) than all other cultivars irrespective of irrigation regimes, followed by cultivar Monty (29.6 O C) under deficit irrigation. During the year 2012, cultivar Hayward maintained significantly higher canopy temperature under deficit irrigation than the remaining treatment combinations and was followed by cultivar Monty under DI. However, the canopy temperature was observed significantly lowest (27.0 O C and 26.8 O C during 2011 and 2012, respectively) in the cultivar Bruno when irrigated at 80 per cent of field capacity, among all other treatment combinations. Pooled analyzed data also revealed that canopy temperature was noticed significantly highest (30.2 O C) in the cultivars Hayward, 118

147 Canopy temperature (%) Allison Hayward Abbott Monty Bruno Cultivars Figure Per cent increase in canopy temperature of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC

148 followed by cultivar Monty (29.7 O C) under deficit irrigation regime and the lowest (26.9 O C) in cultivar Bruno under regular irrigation condition ANATOMICAL AND PHYSIOLOGICAL CHARACTERISTICS AND WATER RELATIONS Stomatal size Stomatal pore length The data on the stomatal pore length of kiwifruit cultivars as affected by irrigation regimes are presented in Table and Figure It is evident from the data (Table ) that the average stomatal pore length of different cultivars was statistically at par under two irrigation regimes. It is evident from the perusal of the data presented in Table that the stomatal pore length of kiwifruit cultivars under two water regimes was significantly variable in during both the years of study. The stomatal pore length of the cultivar Bruno (26.2 µm and 26.1µm in 2011 and 2012, respectively) was significantly higher than all other cultivars. However, the stomatal pore length was noticed significantly least (23.5 µm and 23.4 µm in 2011 and 2012, respectively) in cultivar Monty, among all other cultivars. Similarly, pooled data revealed that stomatal pore length was significantly higher in cultivar Bruno than all other cultivars and significantly least in cultivar Monty. It is revealed from the Figure that the per cent decrease in stomatal pore length by the deficit irrigation treatment was more in cultivar Bruno (0.74 %), while the reduction in stomatal pore length due to deficit irrigation was the least in cultivar Hayward (0.19 %), over the control. The interaction effect of cultivars and irrigation levels on stomatal pore length was also significant. During the year 2011, the stomatal pore length of the cultivar Bruno was significantly higher (26.3 µm & 26.2 µm at 80 and 60 % FC, respectively) irrespective of irrigation treatments than all other treatment combinations except, the cultivar Hayward (25. 8 µm) under both irrigation regimes. In the year 2012, the stomatal pore length was recorded significantly higher in cultivar Bruno irrespective of irrigation regimes in comparison to the remaining treatment combinations. The stomatal pore length was observed 119

149 Table Effect of different irrigation levels on canopy temperature ( o C) of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 80 % FC 60 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C) Table Effect of different irrigation levels on stomatal pore length (µm) of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 60 % FC 80 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C)

150 Reduction in stomatal pore lenmgth (%) Cultivars Allison Hayward Abbott Monty Bruno Figure Per cent reduction in stomatal pore length of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Cultivars Reduction in stomatal pore width (%) Allison Hayward Abbott Monty Bruno Figure Per cent reduction in stomatal pore width of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC

151 Table Effect of different irrigation levels on stomatal pore width (µm) of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 60 % FC 80 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C) Table Effect of different irrigation levels on stomatal density (per 0.04 mm 2 ) of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % of FC 60 % of FC 80 % of FC 60 % of FC 80 % of FC 60 % of FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C)

152 significantly lower in cultivar Monty irrespective of irrigation treatments compared to the remaining treatment combinations. Similarly, pooled data revealed that irrespective of irrigation regimes, the stomatal pore length was observed significantly higher in cultivar Bruno and significantly lower in cultivar Monty in comparison to all other treatment combinations Stomatal pore width The data pertaining to the stomatal pore width of kiwifruit cultivars as influenced by irrigation treatments have been presented in Table and Figure The data in Table clearly indicate that the deficit irrigation affected the stomatal pore width significantly during both the years of study. The leaf stomatal pore width of kiwifruit vines decreased significantly by applying of irrigation at 60 per cent of field capacity in comparison to the vines irrigated at 80 per cent of field capacity. During the year 2011, the average stomatal pore width of different cultivars was reduced from 12.1 µm under irrigation at 80 per cent of field capacity to 10.9 µm under irrigation at 60 per cent of field capacity, whereas in 2012, stomatal pore width decreased from 12.1 µm in control to µm under deficit irrigation. The pooled data also revealed that the stomatal pore width decreased significantly from 12.1 µm in control to 10.9 µm with deficit irrigation. Stomatal pore width also varied significantly among the different cultivars maintained under two water regimes during the course of study (Table ). The maximum stomatal pore width (1 2.3 µm in both years) was noticed in cultivar Hayward, which was significantly higher than the remaining cultivars except, Abbott. However, the stomatal pore width was observed significantly lowest (10. 7µm in both the years) in cultivar Bruno. Similarly, pooled data revealed that stomatal pore width was registered significantly higher in cultivar Hayward (12.3 µm) compared to the other cultivars, and the least in cultivar Bruno (10.7 µm). The Figure depict that the deficit irrigation treatment caused a higher per cent decrease in stomatal pore width in cultivar Bruno (15.1%), 122

153 followed by Allison (12.7%) over control, while the decrease in stomatal pore width due to deficit irrigation was the least in cultivar Hayward (4.4 %). The interaction effect of cultivars and irrigation levels on stomatal pore width was also significant. During both the years, the stomatal pore width was observed significantly highest jointly in cultivars Hayward and Abbott (12.6 µm) when irrigated at 80 per cent of field capacity, among all the treatment combinations. The stomatal pore width was noticed significantly least (9.80 µm and µm during 2011 and 2012, respectively) in the cultivar Bruno when irrigated at 60 per cent of field capacity, compared with all other treatment combinations. Pooled analyzed data clearly revealed that stomatal pore width was found higher in cultivars Hayward and Abbott under control and significantly least in cultivar Bruno (9.80 µm) under deficit irrigation, among all the treatment combination Stomatal density The perusal of the data presented in Table and Figure revealed that the stomatal density of kiwifruit cultivars was significantly influenced by water stress. Vines irrigated at 60 per cent of field capacity produced leaves having higher stomatal density in comparison to the vines irrigated at 80 per cent of field capacity. During the year 2011, the average stomatal density of kiwifruit cultivars increased from 8.47/0.04 mm 2 under irrigation at 80 per cent of field capacity to 8.50/0.04 mm 2 under irrigation at 60 per cent of field capacity. In the year 2012, stomatal density increased to 8.49/ 0.04 mm 2 under water stress treatment from 8.44/0.04 mm 2 in control. The pooled data also revealed that the stomatal density increased significantly with deficit irrigation in comparison to control. It is evident from the perusal of the data presented in Table that the cultivars showed significant variations in stomatal density under two water regimes during both the years of study. The maximum stomatal density (8.79 and 8.76/0.04 mm 2 in 2011 and 2012, respectively) was recorded in cultivar Hayward, which was significantly higher than the remaining cultivars except, the same cultivar under control. The stomatal density was observed however, 123

154 significantly lowest (8.14 and 8.13 in 2011 and 2012, respectively) in cultivar Bruno. Similarly, pooled data revealed that stomatal density was registered significantly higher in cultivar Hayward compared to the remaining four cultivars, and significantly least in cultivar Bruno. It is revealed from the Figure that the per cent increase in the stomatal density due to deficit irrigation treatment was more in cultivar Bruno (0.87 % over the control), while the increase in stomatal density following deficit irrigation over the control was the least in cultivar Hayward (0.11 %). The interaction effect of cultivars and irrigation levels on stomatal density was also significant. During both the years, the stomatal density was observed significantly higher in cultivar Hayward under both the water regimes when compared with all other cultivars irrespective of irrigation treatment. However, the leaves of cultivar Bruno registered the lowest stomatal density (8.11 and 8.08/0.04 mm 2 in 2011 and 2012, respectively) when the irrigation was applied at 80 per cent of field capacity in comparison to all other treatment combinations. Pooled data also revealed that the stomatal density was found significantly higher in cultivar Hayward irrespective of irrigation treatment compared to all other cultivars whether given standard or deficit irrigation, while, it was recorded significantly lowest in cultivar Bruno when irrigation was applied at 80 per cent of field capacity among all the cultivars and irrigation treatments combination Leaf water potential The data on the leaf water potential of kiwifruit cultivars as influenced by water stress are shown in Table and Figure It the study, the irrigation levels exerted a significant influence on leaf water potential (Table ). It was observed that the leaf water potential decreased significantly when kiwifruit vines were subjected to water deficit condition. During the year 2011, the average leaf water potential of different cultivars was reduced significantly from bars under irrigation at 80 per cent of field capacity to bars under irrigation at 60 per cent of field capacity. In the year 2012, leaf water potential decreased from bars in control to bars under water stress treatment. The pooled data also revealed that the leaf 124

155 Stomatal density (%) Allison Hayward Abbott Monty Bruno Cultivars Figure Per cent increase in stomatal density of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Cultivars Reduction in leaf water potential (%) Allison Hayward Abbott Monty Bruno Figure Per cent reduction in leaf water potential of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC

156 Irrigation at 80 % FC Irrigation at 60 % FC A B Plate 2 a Stomatal pore size and density of kiwifruit cv. Allison C D Plate 2 b Stomatal pore size and density of kiwifruit cv. Hayward E F Plate 2 c Stomatal pore size and density of kiwifruit cv. Abbott

157 Irrigation at 80 % FC Irrigation at 60 % FC G H Plate 2 d Stomatal pore size and density of kiwifruit cv. Monty I J Plate 2 e Stomatal pore size and density of kiwifruit cv. Bruno

158 water potential significantly became more negative with deficit irrigation in comparison to control. It is evident from the perusal of the data presented in Table that the cultivars showed significant variations in leaf water potential under two water regimes during both the years of study. The leaf water potential was significantly less negative in cultivar Abbott ( and bars in 2011 and 2012, respectively) than all the remaining cultivars. However, the leaf water potential was observed significantly more negative in cultivar Hayward ( and in 2011 and 2012, respectively) compared with all other cultivars. Similarly, pooled data revealed that leaf water potential was registered significantly higher (less negative) in cultivar Abbott compared to the other cultivars, and the least in cultivar Hayward. The per cent reduction in the leaf water potential by deficit irrigation treatment (Fig ) was more pronounced in cultivar Hayward ( % reduction), while the reduction in leaf water potential by applying lesser than normal irrigation was the least in cultivar Bruno (1.75 %). The interaction effect of cultivars and irrigation levels on leaf water potential was also significant. During the year 2011, the highest leaf water potential (-7.82 and-7.88 bars in 2011 and 2012, respectively) was observed in the cultivar Abbott when irrigated at 80 per cent of field capacity, followed by the same cultivar under deficit irrigation and both of these treatment combinations were significantly superior to all the remaining ones. However, the leaf water potential was significantly lowest ( and bars in 2011 and 2012, respectively) in the cultivar Hayward when irrigated at 60 per cent of field capacity, among all other treatment combinations. Pooled data also showed similar results on this aspect Stomatal resistance The data the stomatal resistance of kiwifruit cultivars under two different irrigation levels have been given in Table and depicted in Figure It is evident from the data (Table ) that stomatal resistance was influenced significantly by different irrigation levels during both the years of 125

159 study. The vines under deficit irrigation developed increased leaf stomatal resistance compared to the vines under control. During the year 2011, the average stomatal resistance of different cultivars increased from 4.05 S cm -1 in vines irrigated at 80 per cent of field capacity to 4.16 S cm -1 in those irrigation at 60 per cent of field capacity. In the year 2012, stomatal resistance increased from 4.06 S cm -1 in control to 4.18 S cm -1 under water stress treatment. The pooled data also revealed that the stomatal resistance increased significantly from 4.06 S cm -1 in control to 4.17 S cm -1 under deficit irrigation. The cultivars exhibited significant variations in stomatal resistance under two water regimes during both the years of study (Table ). During the year 2011, the maximum stomatal resistance (4.31 S cm -1 and 4.32 S cm -1 in 2011 and 2012, respectively) was recorded in cultivar Allison, which was significantly higher than the remaining cultivars. The stomatal resistance was observed significantly lowest (3.99 S cm -1 and 4.00 S cm -1 in 2011 and 2012, respectively) in cultivar Bruno. Similarly, pooled data revealed that stomatal resistance was significantly higher in cultivars Allison (4.31 S cm -1 ) compared to the remaining four cultivars, and the least (4.00 S cm -1 ) in cultivar Bruno. It is revealed from the Figure that the deficit irrigation treatment caused a higher increase in the stomatal resistance in cultivar Bruno (6.30 % ), while the increase in stomatal resistance was the least in cultivar Hayward (1.13 %) over the control. The interaction effect of cultivars and irrigation levels on stomatal resistance was also significant, in this study (Table ). The cultivar Allison displayed maximum stomatal resistance when irrigated at 60 per cent of field capacity (4.37 S cm -1 and 4.38 S cm -1 during 2011 and 2012, respectively), which was significantly higher than all other cultivars irrespective of irrigation treatments. However, the cultivar Bruno exhibited significantly lower stomatal resistance (3.88 S cm -1 and 3.86 S cm -1 during 2011 and 2012 respectively) when irrigated at 80 per cent of field capacity than the remaining treatment combinations. Pooled analyzed data also revealed that stomatal resistance was observed significantly highest in cultivar Allison under deficit irrigation 126

160 Table Effect of different irrigation levels on leaf water potential (-bars) of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % of FC 60 % of FC 80 % of FC 60 % of FC 80 % of FC 60 % of FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C) Table Effect of different irrigation levels on stomatal resistance (S cm -1 ) of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % of FC 60 % of FC 80 % of FC 60 % of FC 80 % of FC 60 % of FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C)

161 Table Effect of different irrigation levels on transpiration rate (m mol m -2 s -1 ) of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % of FC 60 % of FC 80 % of FC 60 % of FC 80 % of FC 60 % of FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C) Table Effect of different irrigation levels on photosynthetic rate (µmol m -2 s -1 ) of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % of FC 60 % of FC 80 % of FC 60 % of FC 80 % of FC 60 % of FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C)

162 Stomatal resistance (%) Allison Hayward Abbott Monty Bruno Cultivars Figure Per cent increase in stomatal resistance of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Cultivars 0 Reduction in transpiration rate (%) Allison Hayward Abbott Monty Bruno Figure Per cent reduction in transpiration rate of exposed leaves of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC

163 (4.38 S cm -1 ), while it was found significantly lowest in cultivar Bruno under control (3.87 S cm -1 ), among all the treatment combinations Transpiration rate The data on the transpiration rate of kiwifruit cultivars in response to irrigation treatments are presented in Table and Figure It is evident from the data (Table ) that transpiration rate of different cultivars was influenced significantly by two irrigation levels during both the years of study. Transpiration rate decreased significantly with the deficit irrigation compared with control. During the year 2011, the average transpiration rate of different cultivars was reduced from 9.6 mmolm -2 s -1 when irrigation was applied at 80 per cent of field capacity to 8.4 mmolm -2 s -1 under deficit irrigation. In the year 2012, transpiration rate decreased to 8.5 mmolm -2 s -1 under water stress treatment from 9.6 mmolm -2 s -1 in control. The pooled data also revealed that the transpiration rate decreased significantly with deficit irrigation in comparison to control. It is evident from the perusal of the data presented in Table that the cultivars showed significant variations in transpiration rate of exposed leaves under two water regimes during both the years of study. The maximum transpiration rate (10.9 mmolm -2 s -1 and 11.0 mmolm -2 s -1 in 2011 and 2012, respectively) was recorded in cultivar Hayward, which was significantly higher than the remaining cultivars. The transpiration rate was observed significantly lowest (5. 4 mmolm -2 s -1 in both the years) in cultivar Bruno. Similarly, pooled data revealed that the transpiration rate was registered significantly higher in cultivars Hayward compared to the remaining cultivars, and the least in cultivar Bruno. It is revealed from the Figure that the per cent decrease in the transpiration rate of leaves by deficit irrigation treatment was more notable in cultivar Bruno (30.2 %), while the decrease in transpiration rate was the least in cultivar Hayward ( 1.81%). The interaction effect of cultivars and irrigation levels on transpiration rate was also significant. The cultivar Hayward exhibited significantly higher 129

164 transpiration rate when irrigated at 80 per cent of field capacity (11.1 mmolm -2 s -1 in both the years) than all other cultivars irrespective of irrigation treatments. However, the transpiration rate was observed significantly lowest (4.4 mmolm -2 s - 1 and 4.5 mmolm -2 s -1 during 2011 and 2012, respectively) in the cultivar Bruno when irrigated at 60 per cent of field capacity, among all other treatment combinations Photosynthetic rate The photosynthetic rate of exposed leaves of kiwifruit cultivars as affected by irrigation treatments have been shown in Table and Figure The photosynthetic rate was affected significantly by different irrigation levels during both the years of study (Table ). The photosynthetic rate decreased significantly when the vines were subjected to soil moisture stress by applying irrigation at 60 per cent of field capacity in comparison to control. During the year 2011, the average photosynthetic rate of different cultivars was reduced from µ molm -2 s -1 under control to µ molm -2 s -1 under water stress irrigation condition. In the next year, again photosynthetic rate decreased significantly to µ molm -2 s -1 under water stress treatment compared to17.79 µ molm -2 s -1 in control. The pooled data also revealed that the photosynthetic rate decreased significantly with deficit irrigation in comparison to control. Different cultivars also varied significantly with respect to photosynthetic rate under two water regimes during both the years of study (Table ). Significantly higher photosynthetic rate was recorded in cultivar Bruno (19.80 µ molm -2 s -1 and µ molm -2 s -1 in 2011 and 2012, respectively) than the remaining cultivars. However, the photosynthetic rate was observed significantly lowest (15.66 and in 2011 and 2012, respectively) in cultivar Hayward. Likewise, pooled data revealed that photosynthetic rate was significantly higher in cultivars Bruno compared to the remaining four cultivars, and the least in cultivar Hayward. It is revealed from the Figure that the per cent reduction in photosynthetic rate leaves due to the deficit irrigation treatment (irrigation at 60% 130

165 Cultivars Reduction in photosynthetic rate (%) Allison Hayward Abbott Monty Bruno Figure Per cent reduction in photosynthetic rate of exposed leaves of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Cultivars Reduction in chlorophyll content (%) Allison Hayward Abbott Monty Bruno Figure Per cent reduction in chlorophyll content of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC

166 FC) was more in cultivar Hayward (4.47%), while the reduction in photosynthetic rate was the least in cultivar Bruno (1.81 % at 60 per cent of FC over 80 per cent of FC ), followed by the cultivar Allison. The interaction of cultivars and irrigation levels on photosynthetic rate was also significant. The cultivar Bruno exhibited significantly higher photosynthetic rate when irrigated at 80 per cent of field capacity (19.98 µ molm - 2 s -1 and µ molm -2 s -1 during 2011 and 2012, respectively) than all other cultivars irrespective of irrigation treatments. However, the photosynthetic rate was significantly lowest (15.31 µ molm -2 s -1 and µ molm -2 s -1 during 2011 and 2012 respectively) in the cultivar Hayward when irrigated at 60 per cent of field capacity, among all other treatment combinations Chlorophyll content The data on the leaf chlorophyll content of kiwifruit cultivars as influenced by different irrigation regimes stress are presented in Table and Figure It is evident from the data (Table ) that chlorophyll content was influenced significantly by different irrigation levels during both the years of study. Chlorophyll content decreased significantly with the imposing of soil moisture stress when compared with control. During the year 2011, the average chlorophyll content of different cultivars was reduced from 3.09 mg/g in control to 2.38 mg/g in deficit irrigation. In the year 2012, chlorophyll content decreased to 2.36 mg/g under water stress treatment from 3.07 mg/g in control. The pooled data also revealed that the average chlorophyll content of different cultivars decreased significantly with deficit irrigation in comparison to control. The cultivars also exhibited significant variations in chlorophyll content of leaves under two different water regimes during both the years of study (Table ). The chlorophyll content was recorded significantly higher in cultivar Allison (2.87 mg/g and 2.85 mg/g in 2011 and 2012, respectively) than the remaining cultivar except, Bruno during the year The chlorophyll content was observed significantly lower in cultivar Hayward (2.59 mg/g in both the years, 2011 and 2012) than the remaining cultivars except, except Abbott in 131

167 2011. Similarly, pooled data revealed that chlorophyll content was registered significantly higher in cultivar Allison compared to the remaining cultivars. However, the chlorophyll content was observed significantly lower in cultivars Hayward and Abbot than the remaining three cultivars. The per cent reduction in the leaf chlorophyll content (Fig ) as caused by deficit irrigation was more pronounced in cultivar Hayward (31.32 %), while the reduction in chlorophyll content was the least in cultivar Bruno (15.41 % at 60 % FC over 80 % FC). The interaction effect of cultivars and irrigation levels on the leaf chlorophyll content was also significant (Table ). The maximum chlorophyll content was observed in cultivar Allison when irrigated at 80 per cent of field capacity (3.14 mg/g and 3.12 mg/g during 2011 and 2012 respectively) which was significantly higher than all treatment combinations except, Cultivars Abbott and Monty under control during The chlorophyll content was observed significantly lowest (2.10 mg/g and 2.11 mg/g during 2011 and 2012 respectively) in the cultivar Hayward when irrigated at 60 per cent of field capacity, among all other treatment combinations except the cultivar Abbot under deficit irrigation Chlorophyll stability index The data on the chlorophyll stability index (CSI) of kiwifruit cultivars as influenced by different irrigation level have been presented in Table and Figure It is evident from the data in Table that the CSI of kiwifruit cultivars increased invariably by subjecting the vines to water stress (irrigation applied at 60 % FC) when compared with the vines control. During the year 2011, the average CSI of different cultivars was increased significantly from 45.3 per cent under control to 53.8 per cent under deficit irrigation. In the year 2012, the average CSI increased from 45.9 per cent in control to 54.3 per cent under deficit irrigation treatment. The pooled data also revealed that the CSI increased significantly with deficit irrigation in comparison to control. 132

168 Table Effect of different irrigation levels on leaf chlorophyll content (mg/g) of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % of FC 60 % of FC 80 % of FC 60 % of FC 80 % of FC 60 % of FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C) Table Effect of different irrigation levels on chlorophyll stability index (%) of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 80 % FC 60 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C)

169 Table Effect of different irrigation levels on proline content (µg/g fresh weight basis) of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 80 % FC 60 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C) Table Effect of different irrigation levels on free amino acids (mg/g fresh weight basis) contents of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 80 % FC 60 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C)

170 Chlorophyll stability index (%) Allison Hayward Abbott Monty Bruno Cultivars Figure Per cent increase in chlorophyll stability index of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC 2.5 Proline content (%) Allison Hayward Abbott Monty Bruno Cultivars Figure Per cent increase in proline content of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC

171 It is clear from the perusal of the data presented in Table that the cultivars showed significant variations in the CSI when subjected to different water regimes, during both the years of study. Significantly higher CSI (64.9 % and 65.0 % in 2011 and 2012, respectively) was recorded in cultivar Hayward as compared to the remaining cultivars. However, significantly lowest value of CSI (31.5 % and 32.3 % in 2011 and 2012, respectively) was noticed in cultivars Bruno. The pooled data revealed that CSI was registered significantly higher in cultivars Hayward (64.9 %) compared to the remaining four cultivars and the average value of CSI was observed significantly least (31.9 %) in cultivar Bruno. The data depicted in the Figure revealed higher increase in the per cent CSI following deficit irrigation in cultivar Bruno (37.5 % over the control), whereas the increase in CSI was marginal in cultivar Hayward (10.5 %). The interaction effect of cultivars and irrigation levels on CSI was also significant. The maximum CSI in leaves was recorded in cultivar Hayward under deficit irrigation regime (68.4 % and 68.0 % during 2011 and 2012 respectively), which was significantly higher than the remaining cultivars irrespective of irrigation treatments. However, the leaves from the cultivar Bruno under control registered significantly lower CSI index (26.5 % and 27.2 % during 2011 and 2012 respectively) in comparison to all other treatment combinations. Likewise, the pooled data also revealed higher CSI in cultivar Hayward (68.2%) under deficit irrigation treatment compared to the remaining treatment combinations. However, The CSI was found to be significantly lowest in cultivar Bruno (26.9 %) when given regular irrigation, among all the treatment combinations Proline content The perusal of the data presented in Table and Figure 4.31 revealed that the proline content of kiwifruit cultivars was significantly influenced by water stress. Accumulation of proline in leaves increased significantly when the vines were irrigated at 60 per cent of field capacity in comparison to the vines under control. During the year 2011, the average leaf proline content of kiwifruit cultivars increased from µg/g fresh weight basis under irrigation at 80 per cent of field capacity to µg/g when the vines were irrigated at 60 per cent 135

172 of field capacity. In the year 2012, leaf proline content increased from µg/g in control to µg/g under water stress treatment. The pooled data also revealed that the proline content increased significantly with deficit irrigation in comparison to control. It is evident from the perusal of the data presented in Table that the cultivars showed significant variations in leaf proline content under two water regimes during both the years of study. The maximum proline content ( and µg/g in 2011 and 2012, respectively) was recorded in cultivar Hayward, which was significantly higher than the remaining cultivars. However, the proline content was observed significantly lower ( and µg/g in 2011 and 2012, respectively) in cultivar Allison in comparison to the remaining cultivars. Similarly, pooled data revealed that leaf proline content was significantly higher in cultivar Hayward ( µg/g) compared to the remaining four cultivars, and significantly least in cultivar Allison ( µg/g). It is revealed from the Figure that the per cent increase in the leaf proline content due to deficit irrigation treatment was more in cultivar Bruno (1.91 %) over the control, while the increase in proline content was the least in cultivar Hayward (0.54 % increase following deficit irrigation over the control). The interaction effect of cultivars and irrigation levels on leaf proline content was also significant. During the year 2011, the leaf proline content was observed significantly higher in cultivar Bruno ( µg/g) when irrigated at 60 per cent of field capacity which was statistically at par with the cultivar Hayward ( µg/g) under deficit irrigation. During the year 2012, the Hayward cultivar registered highest proline content under deficit irrigation ( µg/g) which was statistically at par with same cultivar when subjected to irrigation at 80 per cent of field capacity and Bruno cultivar under DI. However, the leaves of cultivar Allison registered the lowest proline content ( and µg/g in 2011 and 2012, respectively) when the irrigation was applied at 80 per cent of field capacity in comparison to all other treatment combinations except, Monty cultivar irrigated at 80 per cent of field capacity. Pooled data also revealed that the leaf proline content was significantly higher in cultivar Hayward under DI compared to all other cultivars except, Bruno under DI, while, it was recorded 136

173 significantly lowest in cultivar Allison ( µg/g) when irrigation was applied at 80 per cent of field capacity among all the cultivars and irrigation treatments combination except, the cultivar Monty when subjected to irrigation at 80 per cent of field capacity Free amino acids The data on the leaf free amino acids levels of kiwifruit cultivars as influenced by water stress have been presented in Table and Figure It is evident from the data (Table ) that leaf free amino acid content was influenced significantly by different irrigation levels during both the years of study. The deficit irrigation invariably increased the free amino acid contents of kiwifruit vines when compared to the vines provided standard irrigation (control). During the year 2011, the leaf free amino acid contents of different kiwifruit cultivars was significantly increased from 62.2 mg/g fresh weight under irrigation at 80 per cent of field capacity to 70.3 mg/g under irrigation at 60 per cent of field capacity. In the year 2012, the average free amino acids increased from 62.1 mg/g in control to 71.1 mg/g under deficit irrigation treatment. The pooled data also revealed that the free amino acids increased significantly with deficit irrigation in comparison to control. It is evident from the perusal of the data presented in Table that the levels of leaf free amino acid contents differed significantly among the different cultivars maintained under two different water regimes. During both the years, significantly higher leaf free amino acid content (75.8 mg/g and 76.3 mg/g in 2011 and 2012, respectively) was recorded in cultivar Bruno compared with the remaining cultivars. However, free amino acid level was observed significantly lowest (62.4 and 62.5 mg/g in 2011 and 2012, respectively) in cultivar Allison. Likewise, pooled data revealed that the leaf free amino acid level was significantly higher in cultivars Bruno (76.0 mg/g) as compared to the remaining four cultivars. The average value of leaf amino acids content was however, observed significantly lowest (62.4 mg/g) in cultivar Allison. It is revealed from the Figure that in cultivar Bruno, deficit irrigation caused higher per cent increase in leaf free amino acid contents over the 137

174 control (20.0 % increase over control), whereas the increase in free amino acid content was marginal in cultivar Hayward (3.5 %). The interaction effect of cultivars and irrigation levels on free amino acids was also significant. The vines of cultivar Bruno under deficit irrigation regime accumulated significantly higher free amino acids (82.6 and 83.2 mg/g during 2011 and 2012 respectively) in leaves in comparison to the vines of all other cultivars irrespective of irrigation treatments. However, the leaves of the cultivar Allison under control had the least free amino acid concentration (57.2 and 56.4 mg/g during 2011 and 2012, respectively) in comparison to all other treatment combinations. The pooled data also revealed that the level of free amino acids were significantly higher in cultivar Bruno (82.9 mg/g) under deficit irrigation compared to all other cultivars whether irrigated at 60 per cent of FC or at 80 per cent of FC, while, it was recorded significantly lowest in cultivar Allison (56.8 mg/g) when irrigation was applied at 80 per cent of field capacity among all the cultivars and irrigation treatments combination Relative water content The data on the relative water content of kiwifruit cultivars as affected by the irrigation levels are presented in Table and Figure It is evident from the perusal of data in Table that the influence of different irrigation levels on RWC of kiwifruit cultivars was significant, during both the years of study. It was observed that the RWC of vines decreased significantly from 83.4 per cent under control to 60.9 per cent under deficit irrigation and from 83.2 per cent in control to 60.5 per cent under deficit irrigation during the years 2011 and 2012, respectively. The pooled data also revealed that the RWC decreased significantly with deficit irrigation in comparison to control. The data presented in Table revealed that different cultivars showed significant variations in RWC under two water regimes during both the years of study. During the year 2011, significantly higher RWC was recorded in cultivar Allison (77.7 %) than the remaining cultivars. Similarly during the year 2012, the RWC was also found significantly highest in cultivar Allison (76.9 %). 138

175 25.00 Free amino acids (%) Allison Hayward Abbott Monty Bruno Cultivars Figure Per cent increase in free amino acid content of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Cultivars Reduction in RWC (%) Allison Hayward Abbott Monty Bruno Figure Per cent reduction in relative water content of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC

176 However, RWC content was found significantly lowest in cultivar Monty (65.4 and 65.3 % in 2011 and 2012, respectively) in comparison to the remaining cultivars. The pooled data also revealed that the average RWC was greatest in cultivar Allison (77.3 %) which was significantly higher than the remaining cultivars. On the contrary, cultivar Monty exhibited significantly lowest leaf RWC (65.4 %) among all other cultivars. It is evident from the Figure that the reduction in the per cent RWC due to deficit irrigation treatment was highest in cultivar Hayward (38.2 %) lowest in cultivars Bruno (13.5 %). The interaction effect of cultivars and irrigation levels on RWC was also significant. During the year 2011, the RWC was recorded maximum in cultivar Hayward (91.6 %) when irrigated at 80 per cent of field capacity, which was significantly higher than the remaining cultivars and treatment combinations. During this year, the RWC was however, reduced to a greatest extent (55.0 %) in cultivar Monty when irrigated at 60 per cent of field capacity. During 2012, the highest RWC was recorded again in cultivar Hayward (91.2 %) when irrigation was applied at 80 per cent of field capacity, which was significantly higher than the remaining cultivars and treatment combinations. In this year, the RWC was observed significantly lowest in cultivar Monty (54.9 %) when irrigated at 60 per cent of field capacity. It is evident from the pooled data that the RWC was highest in cultivar Hayward (91.4%) with normal irrigation treatment, while it was observed significantly least in cultivar Monty (55.0 %) maintained under deficit irrigation Xylem development Number of primary xylem vessels The count of primary xylem vessels of kiwifruit cultivars as affected by irrigation treatments has been enlisted in Table and further illustrated Figure It is evident from the perusal of the data in Table that the number of primary xylem was affected significantly by deficit irrigation in comparison to control. The average number of primary xylem of different cultivars was reduced 139

177 from 93.9 under control to 90.6 under deficit irrigation treatment, during the year In the next year, the number of primary xylem decreased significantly from 94.5 under control to 90.5 under water stress treatment. The pooled data also revealed that the number of primary xylem decreased significantly with deficit irrigation in comparison to control. Different cultivars under two irrigation regimes also exhibited significant divergence with respect to the number of primary xylem vessels, during both the years of study (Tabl e ). The number of primary xylem was recorded significantly higher in cultivar Hayward (98.5 and 97.9 in 2011 and 2012, respectively) than all other cultivars. However, the number of primary xylem was observed significantly lowest (86.3 and 87.0 in and 2012, respectively) in cultivar Bruno. Likewise, pooled data revealed that number of primary xylem was significantly higher in cultivar Hayward compared to the remaining cultivars, and significantly least in cultivar Bruno. The per cent decrease in the number of primary xylem vessels due to deficit irrigation treatment was more in cultivar Bruno (6.42%) in comparison to control (Fig ). However, the decrease in number of primary xylem due to deficit irrigation was the least (2.14 %) in cultivar Hayward. The interaction effect of cultivars and irrigation levels on the number of primary xylem was also significant. Significantly higher number of primary xylem was recorded in the cultivar Hayward when irrigated at 80 per cent of field capacity (99.5 and 99.0 during 2011 and 2012, respectively) than all other cultivars irrespective of irrigation treatments. However, the number of primary xylem was significantly lowest (83.5 and 84.0 during 2011 and 2012 respectively) in the cultivar Bruno when irrigated at 60 per cent of field capacity, among all other treatment combinations. Likewise, pooled data revealed that the number of primary xylem was significantly higher in cultivar Hayward (99.3) when irrigated at 80 per cent of field capacity compared to the remaining cultivars irrespective of irrigation treatments, and it was found significantly least in cultivar Bruno (83.8) under water stress treatment. 140

178 Irrigation at 80 % FC Irrigation at 60 % FC A B Plate 3 a Xylem vessel development in shoot section of kiwifruit cv. Allison C D Plate 3 b Xylem vessel development in shoot section of kiwifruitit cv. Hayward E F Plate 3 c Xylem vessel development in shoot section of kiwifruit cv. Abbott

179 Irrigation at 80 % FC Irrigation at 60 % FC G H Plate 3 d Xylem vessel development in shoot section of kiwifruitit cv. Monty I J Plate 3 e Xylem vesselel development in shoot section of kiwifruit cv. Bruno

180 Table Effect of different irrigation levels on relative water content (%) of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 80 % FC 60 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C) Table Effect of different irrigation levels on the number of primary xylem of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 80 % FC 60 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C)

181 Table Effect of different irrigation levels on the length of secondary xylem (µm) of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 80 % FC 60 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C) Table Effect of different irrigation levels on cytokinin (ZR ρg/g fresh weight basis) content of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 80 % FC 60 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C)

182 0 Reduction in no. of primary xylem (%) Cultivars Allison Hayward Abbott Monty Bruno Figure Per cent reduction in number of primary xylem of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Reduction in lengtth of secondary xylem (%) Cultivars Allison Hayward Abbott Monty Bruno Figure Per cent reduction in length of secondary xylem of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC

183 Length of secondary xylem vessels The data on the effect of irrigation on the length of secondary xylem vessels of kiwifruit cultivars are presented in Table and Figure The length of secondary xylem of different kiwifruit cultivars was decreased significantly by deficit irrigation, during both the years of study (Table ). During the year 2011, the average length of secondary xylem of different cultivars was significantly decreased from µm in vines under regular irrigation to µm in vines under deficit irrigation. Similarly in 2012, length of secondary xylem decreased significantly from µm in control to µm under water stress treatment. The pooled data also revealed that the length of secondary xylem decreased significantly following deficit irrigation (163.7 µm) in comparison to control (173.0 µm). It is evident from the perusal of the data presented in Table that the development of secondary xylem of the cultivars under two water regimes was significantly diverge during both the years of study. The length of secondary xylem of the cultivar Hayward ( µm and µm in 2011 and 2012, respectively) was significantly higher than all other cultivars. However, the length of secondary xylem was significantly lowest (148.0 and µm in 2011 and 2012, respectively) in cultivar Bruno, among all other cultivars. Similarly, pooled data revealed that length of secondary xylem was significantly higher in cultivar Hayward than all other cultivars and significantly least in cultivar Bruno. It is evident from the Figure that the per cent decrease in the length of secondary xylem as a result of deficit irrigation treatment was more in cultivar Bruno (8.17 %), while the decrease in the length of secondary xylem was the least in cultivar Hayward (3.87 %). The interaction effect of cultivars and irrigation levels on the development of secondary xylem was also significant. The length of secondary xylem was noticed significantly higher in cultivar Hayward when irrigated at 80 per cent of field capacity (195.0 µm & µm in 2011 and 2012, respectively) in comparison to all other treatment combinations. However, the cultivar Bruno developed the secondary xylem having significantly shortest length (142.0 µm 143

184 and µm in 2011 and 2012, respectively) under deficit irrigation treatment in comparison to all other treatment combinations. Similarly, pooled data revealed that length of secondary xylem was significantly higher in cultivar Hayward (194.0 µm) under regular irrigation regime than all other cultivars irrespective of irrigation treatment and significantly least in cultivar Bruno (140.5 µm) under deficit irrigation condition, among all the treatment combinations Endogenous hormones Cytokinin content The data on the zeatin riboside contents of different kiwifruit cultivars as affected by different irrigation regimes are presented in Table and Figure It is evident from the data (Table ) that zeatin riboside content in the leaves of kiwifruit was influenced significantly by different irrigation levels during both the years of study. Zeatin riboside content decreased markedly with the imposing of soil moisture stress by applying deficit irrigation compared with the standard irrigation practice (control). During the year 2011, the average zeatin riboside content of different cultivars decreased significantly from 67.5 ρg/g under control to 53.3 ρg/g under deficit irrigation. Likewise, during the year 2012, zeatin riboside content decreased significantly from 66.6 ρg/g in control to 52.0 ρg/g under deficit irrigation. The pooled data also revealed that the zeatin riboside content decreased significantly following deficit irrigation (52.5 ρg/g) in comparison to control (67.1ρg/g). It is evident from the perusal of the data presented in Table that the zeatin riboside contents of the kiwifruit cultivars under two water regimes was significantly variable during both the years of study. Zeatin riboside content was significantly higher in the cultivar Bruno (78.8 and 79.0 ρg/g in 2011 and 2012, respectively) than all other cultivars. The next superior cultivar was the Allison over the remaining cultivars, with respect to this attribute. However, the zeatin riboside content was significantly lowest (46.5 and 45.4 ρg/g in 2011 and 2012, respectively) in cultivar Hayward, among all other cultivars. Similarly, pooled 144

185 data revealed that zeatin riboside content was significantly highest in cultivar Bruno and significantly least in cultivar Hayward. It is revealed from the Figure that the per cent decrease in zeatin riboside content due to the deficit irrigation treatment was more in cultivar Hayward (42.6 % decrease over the control), while the decrease in zeatin riboside content due to deficit irrigation was the least in cultivar Bruno (5.8 %). The interaction effect of cultivars and irrigation levels on zeatin riboside content was also significant. During the year 2011, cytokinin content of the cultivar Bruno was significantly higher under control (81.5 ρg/g) than all other treatment combinations. However, the level of zeatin riboside was significantly lowest (34.0 ρg/g) in cultivar Hayward when irrigated at 60 per cent of FC. In the year 2012, the highest zeatin riboside content was recorded again in cultivar Bruno (81.0 ρg/g) when irrigated at 80 per cent of field capacity, followed by the same cultivar under deficit irrigation regime (77.0 ρg/g) and these treatment combinations were statistically superior to the remaining treatment combinations. During this year, the zeatin riboside content was observed significantly lowest zeatin riboside content in cultivar Hayward (33.0 ρg/g) when irrigated at 60 per cent of field capacity. Similarly, pooled data revealed that zeatin riboside content was significantly higher in cultivar Bruno (81.3 ρg/g) under control than all other cultivars irrespective of irrigation treatments and significantly least in cultivar Hayward (33.5 ρg/g) under deficit irrigation condition Abscisic acid The data the ABA content of kiwifruit cultivars under two different irrigation regimes have been shown in Table and depicted in Figure It is evident from the data (Table ) that the ABA content of kiwifruit cultivars was influenced significantly by different irrigation levels during both the years of study. The deficit irrigation resulted in the increase of leaf ABA level in compared to the leaves of vines under control. During the year 2011, the average leaf ABA content of different cultivars increased from 34.4 ηg/g fresh weight in vines irrigated at 80 per cent of field capacity to 44.9 ηg/g in those irrigation at 60 per cent of field capacity. In the year 2012, ABA content 145

186 increased from 35.6 ηg/g in control to 46.8 ηg/g under water stress treatment. Similarly, pooled data revealed that the ABA content increased significantly from 35.0 ηg/g in control to 45.8 ηg/g under deficit irrigation. The leaf ABA content of different cultivars under two water regimes was significantly variable during both the years of study (Table ). The maximum leaf ABA content (48.1 ηg/g and 49.5 ηg/g in 2011 and 2012, respectively) was recorded in cultivar Bruno, which was significantly higher than the remaining cultivars, during the respective years. The ABA content was observed significantly lowest (30.5 ηg/g and 32.5 ηg/g in 2011 and 2012, respectively) in cultivar Hayward. Similarly, pooled data revealed that the leaf ABA content was significantly higher in cultivars Bruno (48.8 ηg/g) compared to the remaining four cultivars, and significantly least (31.5 ηg/g) in cultivar Hayward. The illustration of data in Figure clearly shows that deficit irrigation treatment caused a higher per cent increase in the leaf ABA content in cultivar Bruno (44.2 % over the control), while the per cent increase in ABA content was the least in cultivar Hayward (21.1 %). The interaction effect of cultivars and irrigation levels on leaf ABA content was also significant, in this study (Table ). The cultivar Bruno displayed maximum ABA content when irrigated at 60 per cent of field capacity (57.2 and 58.0 ηg/g during 2011 and 2012 respectively), which was significantly higher than all other cultivars and irrigation treatment combinations, in the respective years. However, the cultivar Hayward exhibited significantly lower ABA content (28.0 ηg/g and 29.0 ηg/g 1 during 2011 and 2012 respectively) when irrigated at 80 per cent of field capacity than the remaining treatment combinations of the respective years. Pooled analyzed data also revealed that leaf ABA content was observed significantly highest in cultivar Bruno under deficit irrigation (57.6 ηg/g), while it was found significantly lowest in cultivar Hayward under control (28.5 ηg/g). 146

187 Leaf nutrient status Nitrogen The data on the leaf nitrogen content of kiwifruit cultivars under two different irrigation regimes are presented in Table and Figure It is evident from the data (Table ) that leaf nitrogen content of kiwifruit vines was influenced significantly when subjected to different irrigation regimes. During both the years, the leaf nitrogen content decreased significantly by applying water stress to the vines compared to the vines under control. During the year 2011, the average leaf nitrogen content of different cultivars was reduced from 2.61 per cent under control to 2.54 per cent under water stress. In the year 2012, leaf nitrogen content decreased from 2.62 per cent in control to 2.56 per cent under water stress treatment. The pooled data also revealed that the leaf nitrogen content decreased significantly with deficit irrigation in comparison to control. It is evident from the perusal of the data presented in Table that the leaf nitrogen content of different cultivars maintained under two water regimes was significantly variable during both the years of study. The maximum leaf nitrogen content (3.08 and 3.07 % in 2011 and 2012, respectively) was recorded in cultivar Monty, which was significantly higher than the remaining cultivars, in the respective years. The nitrogen content was observed significantly lowest (2.13 and 2.15 % in 2011 and 2012, respectively) in cultivar Allison. Similarly, pooled data revealed that leaf nitrogen content was significantly higher in cultivar Monty (3.08%) compared to the remaining four cultivars and significantly least (2.14%) in cultivar Allison. It is revealed from the Figure that per cent decrease in leaf nitrogen content as a result of deficit irrigation treatment was higher in cultivar Hayward (3.45 % increase over the control), while the reduction in nitrogen content was the least in cultivar Bruno (2.03 %), followed by the cultivar Allison. The interaction effect of cultivars and irrigation levels on the leaf nitrogen content was also significant. The cultivar Monty had significantly higher leaf nitrogen content when irrigated at 80 per cent of field capacity (3.11 and 3.12 % 147

188 Table Effect of different irrigation levels on ABA (ηg/g fresh weight basis) content of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 80 % FC 60 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C) Table Effect of different irrigation levels on leaf nitrogen content (%) of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 80 % FC 60 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C)

189 Cultivars Reduction in cytokinin content (%) Allison Hayward Abbott Monty Bruno Figure Per cent reduction in cytokinin content of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC ABA content (%) Allison Hayward Abbott Monty Bruno Cultivars Figure Per cent increase in ABA content of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC

190 Table Effect of different irrigation levels on leaf phosphorus content (%) of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 80 % FC 60 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C) Table Effect of different irrigation levels on leaf potassium content (%) of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 80 % FC 60 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C)

191 during 2011 and 2012 respectively) than all other cultivars and irrigation treatment combinations, in the respective years. However, the leaf nitrogen content was significantly lowest (2.09 and 2.13 % during 2011 and 2012 respectively) in the cultivar Allison when irrigated at 60 per cent of field capacity, among all other treatment combinations. Similarly, pooled data revealed that leaf nitrogen content was significantly higher in cultivar Monty (3.12 %) under control than all other cultivars irrespective of irrigation treatments and significantly least in cultivar Allison (2.11 %) under deficit irrigation condition Phosphorus The leaf phosphorus content of kiwifruit cultivars as affected by irrigation treatments have been displayed in Table and Figure The leaf phosphorus content of kiwifruit vines was affected significantly by different irrigation levels during both the years of study (Table ). The level of phosphorus concentration in leaves decreased significantly when the vines were subjected to soil moisture stress by applying irrigation at 60 per cent of field capacity in comparison to control. During the year 2011, the average leaf phosphorus content of different cultivars was reduced from 0.15 per cent under control to 0.10 per cent under deficit irrigation. In the next year, again leaf phosphorus content decreased significantly to 0.11 per cent under water stress treatment compared to 0.16 per cent in control. The pooled data also revealed that the leaf phosphorus content decreased significantly with deficit irrigation in comparison to control. Leaf phosphorus content of different cultivars maintained under different soil water regimes also varied significantly during both the years of study (Table ). During the year 2011, significantly highest leaf phosphorus content (0.15 %) was recorded jointly in cultivars Bruno and Allison, among all the cultivars. During the year 2012, again uppermost level of the leaf phosphorus (0.16%) was noticed in these two cultivars, which was significantly higher as compared to the remaining cultivars. However, during both the years, the phosphorus content was observed to be significantly lower (0.10 and 0.11 % in 2011 and 2012, respectively) in cultivar Hayward as compared to the remaining cultivars, except, 150

192 Cultivars Reduction in nitrogen content (%) Allison Hayward Abbott Monty Bruno Figure Per cent reduction in nitrogen content of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Cultivars Reduction in phosphorus content (%) Allison Hayward Abbott Monty Bruno Figure Per cent reduction in phosphorus content of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC

193 Monty. Likewise, pooled data revealed that leaf phosphorus content was significantly highest (0.16%) jointly in cultivars Bruno and Allison compared to the remaining cultivars and the significantly lower in cultivar Hayward in compared to the remaining cultivars except, Monty. It is revealed from the Figure that the per cent reduction in leaf phosphorus content due to the deficit irrigation treatment was more in cultivar Hayward (55.2% ), while the reduction in phosphorus content was the least in cultivar Bruno (12.2 % under irrigation at 60 % FC over irrigation at 80 % FC), followed by the cultivar Allison. The interaction effect of cultivars with irrigation levels on leaf phosphorus content was also significant. The cultivar Allison exhibited significantly higher leaf phosphorus content when irrigated at 80 per cent of field capacity (0.17 % and 0.18 % during 2011 and 2012, respectively) than all other cultivars irrespective of irrigation treatments except Bruno under control. However, the phosphorus content was significantly lowest (0.06 and 0.07 % during 2011 and 2012 respectively) in the cultivar Hayward when irrigated at 60 per cent of field capacity, among all other treatment combinations Potassium The data on the leaf potassium content of kiwifruit cultivars as affected by irrigation regimes are presented in Table and Fig It is evident from the data (Table ) that leaf potassium content was influenced significantly by different irrigation levels during both the years of study. Leaf potassium content decreased significantly when the vines were subjected to water stress by applying deficit irrigation at 60 per cent of field capacity. During the year 2011, the average leaf potassium content of different cultivars was decreased significantly from 2.30 per cent under irrigation at 80 per cent of field capacity to 2.21 per cent under irrigation at 60 per cent of field capacity. Similarly, leaf potassium content decreased significantly from 2.29 per cent in control to 2.17 per cent under water stress treatment, in the year The pooled data also revealed that the leaf potassium content decreased significantly following deficit irrigation (2.30%) in comparison to control (2.19%). 151

194 It is evident from the perusal of the data presented in Table that the leaf potassium content of kiwifruit cultivars differed significantly when their vines were maintained under two different water regimes, during both the years of study. The leaf potassium content of cultivar Hayward was significantly higher (2.43 and 2.41% in 2011 and 2012, respectively) than all other cultivars except, Allison in However, the leaf potassium content was significantly lowest (2.0 and 1.99 % in 2011 and 2012, respectively) in cultivar Bruno, among all other cultivars. Similarly, pooled data revealed that leaf potassium content was significantly higher in cultivar Hayward than all other cultivars and significantly least in cultivar Bruno. The per cent decrease in leaf potassium level due to deficit irrigation (irrigation at 60 % FC) was more in cultivar Hayward (6.40 % over the control), while the decrease in leaf potassium content due to deficit irrigation over irrigation at 80 per cent of FC was the least (3.23 %) in cultivar Bruno ( Fig ). The interaction effect of cultivars and irrigation levels on leaf potassium content was also significant. The higher leaf potassium content was recorded in cultivar Hayward (2.50 and 2.49 % in 2011 and 2012, respectively) when irrigated at 80 per cent of FC, which was significantly higher than all other treatment combinations. The leaf potassium content was however, observed significantly lower in cultivar Bruno (1.97 and 1.95 % in the year 2011 and 2012, respectively) when irrigated at 60 per cent of field capacity in comparison to all other treatment combinations. Similarly, pooled data revealed that leaf potassium content was significantly higher in cultivar Hayward (2.50%) under regular irrigation regime than all other treatment combinations and significantly least in cultivar Bruno (1.96 %) under deficit irrigation condition Calcium The data on the calcium content is of kiwifruit cultivars as affected by irrigation treatments are presented in Table and Figure It is clear from the data (Table ) that leaf calcium contents of kiwifruit cultivars were influenced significantly by different irrigation levels. It 152

195 Cultivars Reduction in potassium content (%) Allison Hayward Abbott Monty Bruno Figure Per cent reduction in potassium content of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Cultivars Reduction in Calcium content (%) Allison Hayward Abbott Monty Bruno Figure Per cent reduction in calcium content of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC

196 was observed that the leaf calcium content decreased with the deficit irrigation treatment compared with regular irrigation (control). During the year 2011, the average leaf calcium content of different cultivars was decreased significantly from 3.90 per cent under irrigation at 80 per cent of field capacity to 3.83 per cent under irrigation at 60 per cent of field capacity. Similarly in the year 2012, leaf calcium content decreased significantly from 3.90 per cent in control to 3.82 per cent under water stress treatment. The pooled data also revealed that the calcium content decreased significantly following deficit irrigation (3.83%) in comparison to control (3.90%). It is evident from the perusal of the data presented in Table that the leaf calcium content of kiwifruit cultivars under two water regimes differed significantly, during both the years of study. Average leaf calcium content of the cultivar Monty (4.18 and 4.20 % in 2011 and 2012, respectively) was significantly higher than all other cultivars. However, the level of leaf calcium was significantly lowest (3.72 and 3.71 % in 2011 and 2012, respectively) in cultivar Abbott, among all other cultivars. Similarly, pooled data revealed that the leaf calcium content was significantly higher in cultivar Monty than all other cultivars and significantly least in cultivar Abbott. It is revealed from the Figure that the per cent decrease in the leaf calcium level as a result of deficit irrigation treatment was more pronounced in cultivar Hayward (2.81 %), while the reduction in calcium content due to deficit irrigation was the least in cultivar Bruno (0.73 %). The interaction effect of cultivars and irrigation levels on leaf calcium content was also significant. During both the years, leaf calcium content was recorded significantly higher in cultivar Monty (4.23 and 4.24 % at 80 % FC in 2011 and 2012, respectively) under control than all other treatment combinations. However, the level of leaf calcium was observed significantly lower in cultivar Abbott (3.69 and 3.65 % in the year 2011 and 2012, respectively) when irrigated at 60 per cent of field capacity in comparison to all other cultivars, irrespective of irrigation treatments. Similarly, pooled data revealed that leaf calcium content was significantly higher in cultivar Monty (4.24%) under regular irrigation regime in comparison to all other cultivars and irrigation treatment combinations. 153

197 Table Effect of different irrigation levels on leaf calcium content (%) of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 80 % FC 60 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C) Table Effect of different irrigation levels on leaf magnesium content (%) of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 80 % FC 60 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C)

198 Conversely, leaf calcium level was significantly least in cultivar Abbott (3.67 %) under deficit irrigation condition Magnesium The leaf magnesium content of kiwifruit cultivars as affected by irrigation treatments have been shown in Table and Figure The perusal of the data (Table ) reveals that the leaf magnesium content of kiwifruit cultivars was affected significantly by deficit irrigation in comparison to control. The average leaf magnesium content of different cultivars was reduced from 0.37 per cent under regular irrigation to 0.33 per cent under deficit irrigation treatment, during the year In the next year, again the water stress treatment decreased the leaf magnesium content significantly (0.38 %) as compared to control (0.34 %). The pooled data also revealed that the leaf magnesium content decreased significantly with deficit irrigation in comparison to control. Different cultivars varied significantly with respect to leaf magnesium content under two water regimes ( Table ). In both the years, leaf magnesium content was recorded significantly higher in cultivar Monty (0.37 and 0.38 % in 2011 and 2012, respectively) which was however, statistically at par with Allison and Abbott. However, magnesium content was observed lowest (0.33 and 0.34 % in 2011 and 2012, respectively) in cultivar Hayward, which was however, statistically at par with Bruno and Abbott in 2011 and Bruno in Likewise, pooled data revealed that leaf magnesium content was significantly highest in cultivar Monty. Its average value was observed least in cultivar Hayward, which was however, statistically at par with Bruno. It is evident from the Figure that the per cent reduction in leaf magnesium content due to the deficit irrigation treatment was highest in cultivar Hayward (16.2%), and the least in cultivar Bruno (5.6 % over the control ). The interaction of cultivars and irrigation levels on magnesium content was also significant. The cultivar Monty exhibited significantly higher leaf magnesium content when irrigated at 80 per cent of field capacity (0.39 % and 0.40 % during 2011 and 2012, respectively) than all other cultivars irrespective of 155

199 irrigation treatments except Allison and Abbott under control. However, the leaf magnesium content was significantly lowest (0.30 and 0.31 % during 2011 and 2012 respectively) in the cultivar Hayward when irrigated at 60 per cent of field capacity, among all other treatment combinations except Abbott under deficit irrigation in Pooled data revealed that the leaf magnesium content was significantly higher in cultivars Abbot and Monty under regular irrigation (0.40 %) compared to the remaining cultivars irrespective of irrigation treatments, and significantly lowest in cultivar Hayward at water deficit condition (0.31 %), among all the treatment combinations FRUIT QUALITY Fruit size and weight Fruit length The data on the fruit length of kiwifruit cultivars as influenced by different irrigation regimes are presented in Table and Figure It is evident from the data in Table that the fruit length was significantly influenced by different irrigation levels during both the years of study. The fruit length decreased following the treatment of deficit irrigation compared with control. During the year 2011, the average fruit length of different cultivars was reduced from 78.1 mm under control to 75.1 mm under deficit irrigation. In the year 2012, fruit length decreased to 74.3 mm under deficit irrigation from 77.5 mm in control. The pooled data also revealed that the fruit length decreased significantly following the application of deficit irrigation treatment in comparison to regular irrigation. The average fruit length of different cultivars varied significantly in response to irrigation treatments during both the years of study (Table ). The maximum fruit length (91.4 and 91.1mm in 2011 and 2012, respectively) was recorded in cultivar Bruno, which was significantly higher than the remaining cultivars. The fruit length was observed significantly lowest (69.1 and 68.1 mm in 2011 and 2012, respectively) in cultivar Hayward. Similarly, pooled data revealed that fruit length was registered significantly higher in cultivar 156

200 Cultivars Reduction in magnesium content (%) Allison Hayward Abbott Monty Bruno Figure Per cent reduction in magnesium content of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Cultivars Reduction in fruit length (%) Allison Hayward Abbott Monty Bruno Figure Per cent reduction in fruit length of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC

201 Bruno compared to the remaining four cultivars, and significantly least in cultivar Hayward. The decrease in fruit length due to deficit irrigation was greater in cultivar Hayward (7.72 % decrease over the control), while the decrease in fruit length due to deficit irrigation was the least in cultivar Bruno (2.01 %), followed by the cultivar Allison (Fig ). The interaction effect of cultivars and irrigation levels on fruit length was also significant. Fruits of cultivar Bruno recorded significantly higher length (92.3 mm and 92.0 mm during 2011 and 2012 respectively) when its vines were irrigated at 80 per cent of field capacity than all other cultivars irrespective of irrigation treatments. However, the fruit length was observed significantly lowest (66.4 mm and 65.2 mm during 2011 and 2012 respectively) in the cultivar Hayward when irrigated at 60 per cent of field capacity, among all other treatment combinations. Similarly, pooled data revealed that fruit length was significantly higher in cultivar Bruno (92.2 mm) under regular irrigation regime than all other cultivars irrespective of irrigation treatments and significantly least in cultivar Hayward (65.8 mm) under deficit irrigation condition Fruit diameter The data on the fruit diameter of kiwifruit cultivars under different irrigation regimes are presented in Table and Figure It is evident from the data (Table ) that fruit diameter was influenced significantly by different irrigation levels during both the years of study. Fruit diameter decreased with the decrease in the supply of irrigation water compared with control. During the year 2011, the average fruit diameter was reduced from 45.8 mm under control to 42.1 mm under deficit irrigation. In the year 2012, fruit diameter was observed significantly lower under water stress treatment (41.6 mm) than control (45.5 mm). The pooled data also revealed that the fruit diameter decreased significantly with deficit irrigation (41.8 mm) in comparison to control (45.7 mm). It is evident from the perusal of the data presented in Table that the cultivars showed significant variations in fruit diameter under different water 157

202 regimes during both the years of study. The maximum fruit diameter (49.6 and 49.4 mm in 2011 and 2012, respectively) was recorded in cultivar Hayward, which was significantly higher than the remaining cultivars. However, the fruit diameter was recorded significantly lowest in cultivar Bruno among all other cultivars during both the years ( 40.4 mm and 40.1 mm in 2011 and 2012, respectively). Likewise, pooled data revealed that fruit diameter was significantly higher in cultivar Hayward as compared to all other cultivars and significantly least in cultivar Bruno. It is revealed from the Figure that the per cent decrease in fruit diameter due to deficit irrigation was highest in cultivar Hayward (15.3 %), and the least in cultivar Bruno (3.4 %). The interaction effect of cultivars and irrigation levels on fruit diameter was also significant. The fruit diameter was significantly higher in the cultivar Hayward (53.7 mm and 53.5 mm in 2011 and 2012, respectively) when irrigated at 80 per cent of field capacity in comparison to the remaining cultivars irrespective of irrigation treatments. However, the fruit diameter was recorded significantly lowest (39.1 and 38.5 % during 2011 and 2012, respectively) in cultivar Abbott when irrigated at 60 per cent of field capacity, among all other treatment combinations. Pooled data also revealed that fruit diameter was significantly highest in cultivar Hayward (53.6 mm) when irrigated at 80 per cent of field capacity and significantly lowest in cultivar Abbott (38.8 mm) when irrigated at 60 per cent of field capacity among all the treatment combinations Fruit weight The data on the fruit weight of kiwifruit cultivars as affected by the irrigation levels are presented in Table and Figure It is evident from the perusal of data (Table ) that the influence of different irrigation levels on fruit weight was significant, during both the years of study. It was observed that the fruit weight decreased significantly with deficit irrigation treatment compared to the control. During the year 2011, the average fruit weight of different cultivars was decreased from 85.5 g in vines under the irrigation treatment at 80 per cent of field capacity to 82.1 g under irrigation 158

203 T1 Irrigation at 80% EC T2 Irrigation at 60% EC Allison Hayward Allison Hayward Abbott Monty Abbott Monty Bruno Bruno Plate 4 Effect of irrigation levels on fruit size of different kiwifruit cultivars

204 Cultivars Reduction in fruit diameter (%) Allison Hayward Abbott Monty Bruno Figure Per cent reduction in fruit diameter of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Cultivars Reduction in fruit weight (%) Allison Hayward Abbott Monty Bruno Figure Per cent reduction in fruit weight of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC

205 Table Effect of different irrigation levels on fruit length (mm) of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 80 % FC 60 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C) Table Effect of different irrigation levels on fruit diameter (mm) of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 80 % FC 60 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C)

206 Table Effect of different irrigation levels on fruit weight (g) of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 80 % FC 60 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C) Table Effect of different irrigation levels on fruit firmness (Kg/cm 2 ) of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 80 % FC 60 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C)

207 treatment at 60 per cent of field capacity. In the year 2012, again the fruit weight decreased significantly to 82.6 g under deficit irrigation treatment from 86.1 g in control. The pooled data (Table ) also revealed that the fruit weight decreased significantly with deficit irrigation in comparison to control. The data presented in Table revealed that the cultivars showed significant variations in fruit weight under two water regimes during both the years of study. During the year 2011, significantly greater fruit weight was recorded in cultivar Bruno (88.0 g) than the remaining cultivars and significantly least in cultivar Monty (81.4 g) which was however, statistically at par with cultivar Hayward (81.6). During the year 2012, the fruit weight was observed significantly higher in cultivar Allison (88.2 g) among all the remaining cultivars and the significantly least was observed in cultivar Hayward (80.7 g). The pooled data revealed that the average fruit weight was significantly higher in cultivar Bruno (87.8 g) than the remaining cultivars. Conversely, the vines of cultivars Monty and Hayward produced fruits having significantly lowest weight than the remaining three cultivars. It is evident from the Figure that the per cent reduction in the fruit weight due to deficit irrigation treatment was higher in cultivar Hayward (7.7 6 %) while the per cent reduction in fruit weight was lower in cultivars Bruno (1.53 %). The interaction effect of cultivars and irrigation levels on fruit weight was also significant. During the year 2011, the fruit weight was recorded maximum in cultivar Bruno (88.6 g) when irrigated at 80 per cent of field capacity, which was however, statistically at par with the same cultivar irrigated at 60 per cent of field capacity. However in this year, the fruit weight was registered minimum (80.2 g) in cultivar Abbott when irrigated at 60 per cent of field capacity. During the year 2012, the maximum fruit weight was recorded in cultivar Allison (89.0 g) under regular irrigation regime, which was significantly higher than the remaining cultivars and irrigation treatment combinations. In this year, the fruit weight was recorded significantly lowest in cultivar Hayward (77.2 g) when irrigated at 60 per cent of field capacity. It is evident from the pooled data (Table ) that among all other treatment combinations, the fruit weight was recorded 161

208 significantly higher in cultivar Bruno (88.5 g) under regular irrigation treatment, and significantly least in cultivar Hayward (77.9 g) under deficit irrigation Fruit firmness The data on the total fruit firmness of kiwifruit cultivars as affected by irrigation regimes are presented in Table and Figure The data in Table clearly show that the fruit firmness was influenced significantly by different irrigation levels during both the years of study. The fruit firmness of different cultivars increased significantly following the application of deficit irrigation compared with standard irrigation practice (control). During the year 2011, the average fruit firmness of different cultivars was increased significantly from 5.59 kg/cm 2 under control to 5.92 kg/cm 2 under deficit irrigation. Similarly, the fruit firmness increased significantly from 5.62 kg/cm 2 in control to 5.98 kg/cm 2 under deficit irrigation treatment, in the year The pooled data also revealed that the fruit firmness increased significantly following deficit irrigation (5.60 kg/cm 2 ) in comparison to control (5.95 kg/cm 2 ). The data presented in Table revealed that the fruit firmness of different cultivars of kiwifruit in response to irrigation treatments was influenced significantly during both the years of study. The fruit firmness was found to be significantly higher in cultivar Bruno (6.70 and 6.76 kg/cm 2 in 2011 and 2012, respectively) than all the remaining cultivars. Conversely, the fruit firmness was recorded significantly lowest in cultivar Monty (5.18 and 5.24 kg/cm 2 in 2011 and 2012, respectively) in comparison to the remaining cultivars. Similarly, pooled data revealed that the fruit firmness was found significantly higher in cultivar Bruno than remaining all other cultivars and significantly least in cultivar Monty. It is apparent from the Figure that the per cent increase in fruit firmness caused by the deficit irrigation treatment was more in cultivar Hayward (9.60 %), while the decrease in fruit firmness due to deficit irrigation was the least in cultivar Bruno (1.58 % ). The interaction effect of cultivars and irrigation levels on the fruit firmness was also significant. The cultivar Bruno exhibited significantly higher 162

209 Fruit firmness (%) Allison Hayward Abbott Monty Bruno Cultivars Figure Per cent increase in firmness of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Fruit TSS (%) Allison Hayward Abbott Monty Bruno Cultivars Figure Per cent reduction in TSS content of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC

210 fruit firmness when irrigated at 60 per cent of field capacity (6.75 & 6.81 kg/cm 2 during 2011 and 2012, respectively) than all other treatment combinations. The fruit firmness was observed significantly lower in cultivar Monty (5.00 and 5.05 kg/cm 2 during the year 2011 and 2012, respectively) under regular irrigation regime than all other treatment combinations. Similarly, pooled data revealed that the fruit firmness was significantly higher in cultivar Bruno (6.78 Kg/cm 2 ) under deficit irrigation condition than all other cultivars irrespective of irrigation treatments and significantly least in cultivar Monty (5.03 kg/cm 2 ) under regular irrigation regime Total soluble solids The perusal of the data presented in Table and Figure 4.47 revealed that the total soluble solids (TSS) content of kiwifruit cultivars was significantly influenced by water stress. Vines irrigated at 60 per cent of field capacity produced fruits having higher TSS in comparison to the vines irrigated at 80 per cent of field capacity. During the year 2011, the average fruit TSS content of kiwifruit cultivars increased from 14.5 o Brix under control to 16.2 o B under deficit irrigation. In the year 2012, fruit TSS content increased from 14.6 o B in control to 16.5 o B under water stress treatment. The pooled data (Table ) also revealed that the fruit TSS increased significantly with deficit irrigation in comparison to control. It is evident from the perusal of the data presented in Table that the fruits of kiwifruit cultivars showed significant variations in TSS contents in response to different water regimes during both the years of study. The maximum fruit TSS (16.7 and 17.0 o B in 2011 and 2012, respectively) was recorded in cultivar Hayward, which was significantly higher than the remaining cultivars. However, the TSS was observed significantly lower (14.3 and 14.5 in 2011 and 2012, respectively) in fruits of cultivar Monty in comparison to the remaining cultivars except. Similarly, pooled data revealed that the fruit TSS content was registered significantly higher in cultivar Hayward compared to the remaining four cultivars, and significantly least in cultivar Monty. 163

211 It is revealed from the Figure that the per cent increase in the fruit TSS due to deficit irrigation treatment was more in cultivar Hayward (19.6 % increase over the control), while the increase in fruit TSS was the least in cultivar Bruno (6.0 %). The interaction effect of cultivars and irrigation levels on fruit TSS content was also significant. During both the years, the content of TSS was observed significantly higher in fruits from cultivar Hayward (18.1 and 18.5 o B in 2011 and 2012, respectively) under deficit irrigation regimes when compared with all other cultivars irrespective of irrigation treatment. However, the fruits of cultivar Monty registered the lowest TSS (13.5 and 13.6 o B in 2011 and 2012, respectively) when the irrigation was applied at 80 per cent of field capacity in comparison to all other treatment combinations. Pooled data also revealed that the fruit TSS content was found significantly higher in cultivar Hayward (18.3 o B) under deficit irrigation, while it was recorded significantly lowest in cultivar Monty (13.6 o B) when irrigation was applied at 80 per cent of field capacity among all the cultivars and irrigation treatments combination Titratable acidity The data on the titratable acidity in fruits of different kiwifruit cultivars as influenced by irrigation treatments are shown in Table and depicted in Figure The irrigation levels exerted a significant influence on titratable acid contents of kiwifruit during the course of study. It was observed that the fruit titratable acidity decreased significantly when kiwifruit vines were subjected to deficit irrigation. During the year 2011, the average fruit titratable acidity of different cultivars was reduced significantly from 1.21 per cent in control to 1.12 per cent under deficit irrigation. In the year 2012, titratable acid content of kiwifruits decreased from 1.20 per cent in control to 1.07 per cent under deficit irrigation. The pooled data also revealed that the fruit titratable acidity decreased significantly with deficit irrigation (1.20 %) in comparison to control (1.10 %). It is evident from the perusal of the data presented in Table that different cultivars showed significant variations in fruit titratable acidity under 164

212 Reduction in titratable acidity (%) Cultivars Allison Hayward Abbott Monty Bruno Figure Per cent reduction in titratable acidity of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Total sugars (%) Allison Hayward Abbott Monty Bruno Cultivars Figure Per cent increase in total sugars of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC

213 two water regimes during both the years of study. During both the years, the titratable acidity in fruit was observed significantly higher in cultivar Bruno than all the remaining cultivars except Monty. However, fruit titratable acidity was observed significantly least in cultivar Hayward (1.07& 1.03 % in 2011 & 2012, respectively) among all the cultivars. Similarly, pooled data revealed that fruit titratable acidity was registered significantly higher in cultivar Bruno (2.13 %) compared to the other cultivars except Monty, while the least fruit acid content was recorded in cultivar Hayward (1.05%). The per cent reduction in the fruit titratable acidity following deficit irrigation treatment (Fig ) was more pronounced in cultivar Hayward (23.2 %), while the reduction in fruit titratable acidity due to deficit irrigation was the least in cultivar Bruno (1.7 %). The interaction effect of cultivars and irrigation levels on fruit titratable acidity was also significant. During the year 2011, the highest titratable acidity (1.24 % and 1.23 % in 2011 and 2012, respectively) was observed in the cultivar Monty when its vines were irrigated at 80 per cent of field capacity in comparison to all other cultivars irrespective of irrigation treatments. However, the fruit titratable acidity was found significantly lowest (0.94 % and 0.88 % in 2011 and 2012, respectively) in the cultivar Hayward under deficit irrigation, among all other treatment combinations. Pooled data also showed similar results on this aspect Sugar content Total sugars The perusal of the data presented in Table and Figure 4.49 revealed that the fruit total sugar content of different kiwifruit cultivars was significantly influenced by irrigation treatments. The fruits from vines irrigated at 60 per cent of field capacity had significantly higher total sugar content in comparison to those from vines irrigated at 80 per cent of field capacity. During the year 2011, the average total sugar content in fruits of different cultivars increased from 8.51 per cent under regular irrigation to 9.26 per cent under deficit irrigation. In the year 2012, fruit total sugars increased to 9.34 per cent under deficit irrigation 165

214 treatment from 8.55 per cent in control. The pooled data also revealed that the total sugar content increased significantly with deficit irrigation in comparison to control. The data presented in Table clearly indicate that the total sugar contents in fruits differed significantly among the different cultivars maintained under two soil water regimes, during both the years of study. The maximum total sugar content (9.75 and 9.81% in 2011 and 2012, respectively) was recorded in cultivar Hayward, which was significantly higher than the remaining cultivars. However, the fruit total sugar content was observed significantly lower (8.14 and 8.17 per cent in 2011 and 2012, respectively) in cultivar Bruno in comparison to the remaining cultivars. Likewise, pooled data revealed that the fruit total sugar content was significantly higher in cultivar Hayward compared to the remaining four cultivars, and significantly least in cultivar Bruno. It is revealed from the Figure that the per cent increase in total sugars in fruits due to deficit irrigation treatment was more in cultivar Hayward (15.9 % increase over the control), and the least in cultivar Bruno (0.4 %). The cultivars and irrigation levels showed significant interaction effects on total sugar content of fruits (Table ). During both the years, the total sugar content was observed significantly higher in cultivar Hayward (10.45 and % in 2011 and 2012, respectively) under deficit irrigation in comparison to all other cultivars irrespective of irrigation treatments. However, the fruits of cultivar Monty had the lowest total sugar contents (8.07 and 8.11 % in 2011 and 2012, respectively) when the irrigation was applied at 80 per cent of field capacity in comparison to all other treatment combinations. Pooled data also revealed that the total sugar content of fruits was found significantly higher in cultivar Hayward (10.50 %) under deficit irrigation as compared to all other cultivars irrespective of irrigation treatments, while among all the cultivars and irrigation treatments combination, it was recorded significantly lowest in cultivar Monty (8.09 %) under control. 166

215 Table Effect of different irrigation levels on fruit TSS ( 0 B) content of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 80 % FC 60 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C) Table Effect of different irrigation levels on fruit titratable acidity (%) of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 80 % FC 60 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C)

216 Table Effect of different irrigation levels on fruit total sugars (%) content of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 80 % FC 60 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C) Table Effect of different irrigation levels on fruit reducing sugars (%) content of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 80 % FC 60 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C)

217 Reducing sugars The data on the fruit reducing sugar contents of different kiwifruit cultivars under two different irrigation levels have been given in Table and depicted in Figure It is evident from the data in Table that the fruit reducing sugar content was influenced significantly by different irrigation levels during both the years of study. The deficit irrigation increased the fruit reducing sugars content over the control. During the year 2011, the average reducing sugar content in fruits of different cultivars increased from 5.86 per cent in control to 6.55 per cent under deficit irrigation. In the year 2012, fruit reducing sugars significantly increased from 5.87 per cent in control to 6.60 per cent under deficit irrigation. The pooled data also revealed that the content of reducing sugar increased significantly from 5.87 per cent in fruits from vines irrigated at 80 per cent of field capacity to 6.58 per cent in fruits from vines irrigated at 60 per cent of field capacity. The cultivars exhibited significant variations in fruit reducing sugar contents under two water regimes (Table ). During both the years, the maximum fruit reducing sugar content (7.62 % and 7.65 % in 2011 and 2012, respectively) was recorded in cultivar Hayward, which was significantly higher than the remaining cultivars. The fruit reducing sugar content was however, observed significantly lowest (5.41 % and 5.45 % in 2011 and 2012, respectively) in cultivar Monty. Similarly, pooled data revealed that the fruit reducing sugar content was registered significantly higher in cultivar Hayward (7.63 %) compared to the remaining four cultivars and the significantly least (5.43 %) in cultivar Monty. The per cent increase in fruit reducing sugar content (Fig ) due to deficit irrigation treatment was highest in cultivar Hayward (24.0 % ) and the lowest in cultivar Bruno (6.4 %). The interaction effect of cultivars and irrigation levels on the fruit reducing sugar content was also significant, in this study (Table ). The cultivar Hayward accumulated significantly higher reducing sugar in fruits when 169

218 its vines were irrigated at 60 per cent of field capacity (8.43 and 8.47 % during 2011 and 2012, respectively) than all other cultivars irrespective of irrigation treatments. However, the cultivar Monty exhibited significantly lower fruit reducing sugar content (5.16 % and 5,18 % during 2011 and 2012, respectively) under control than the remaining treatment combinations. Pooled analyzed data also revealed that fruit reducing sugar content was observed significantly highest in cultivar Hayward under deficit irrigation (8.45 %), while it was found significantly lowest in cultivar Monty under control (5.17 %), among all the treatment combinations Non reducing sugars The data on the non-reducing sugar contents in fruits of different kiwifruit cultivars under two distinct irrigation regimes have been displayed in Table and depicted in Figure The level of non-reducing sugars in fruit increased significantly when kiwifruit vines were subjected to deficit irrigation as compared to the regular irrigation (Table ). During the year 2011, the average non-reducing sugars in fruits increased from 2.38 per cent in control to 2.77 per cent under deficit irrigation. In the year 2012, non-reducing sugar levels in fruits increased from 2.40 per cent in control to 2.82 per cent under water stress. The pooled data also revealed that the fruit non reducing sugar contents increased significantly with the deficit irrigation treatment (2.79%) in comparison to control (2.39%). The cultivars exhibited significant variations in fruit non-reducing sugar levels under two different irrigation levels during both the years of study. Significantly higher fruit non-reducing sugar contents were recorded in cultivar Monty (3.01 and 3.03 % in 2011 and 2012, respectively) than the remaining cultivars. The non-reducing sugar contents were observed significantly lowest (2.28 and 2.30% in 2011 and 2012, respectively) in fruits of cultivar Allison. Similarly, pooled data revealed that non-reducing sugar contents of fruits were significantly higher in cultivars Monty (3.02 %) compared to the remaining four cultivars and significantly least (2.29 %) in cultivar Allison which was statistically at par with cultivar Bruno (2.30). 170

219 Reducing sugar (%) Allison Hayward Abbott Monty Bruno Cultivars Figure Per cent increase in reducing sugars of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC Non reducing sugars (%) Allison Hayward Abbott Monty Bruno Cultivars Figure Per cent increase in non reducing sugars of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC

220 Table Effect of different irrigation levels on fruit non-reducing sugars (%) content of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 80 % FC 60 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C) Table Effect of different irrigation levels on fruit ascorbic acid (mg/100g) content of kiwifruit cultivars Cultivars 2011 Mean 2012 Mean Pooled Mean Irrigation treatments Irrigation treatments Irrigation treatments 80 % FC 60 % FC 80 % FC 60 % FC 80 % FC 60 % FC Allison Hayward Abbott Monty Bruno Mean CD Pooled Irrigation treatments (I) Cultivars (C) Irrigation treatments X Cultivars (I X C)

221 It is revealed from the Figure that the deficit irrigation treatment caused a higher per cent increase in the non reducing sugars in cultivar Hayward (35.9 % increase over control), conversely, the increase in non-reducing sugars was the least in cultivar Bruno (1.1 %). The interaction effect of cultivars and irrigation treatments on fruit nonreducing sugar levels was also significant, in this study. The vines cultivar Monty accumulated significantly higher non-reducing sugar in fruits when irrigated at 60 per cent of field capacity (3.25 % and 3.28 % during 2011 and 2012 respectively) than the all other cultivars irrespective of irrigation treatments. However, the fruits of cultivar Hayward under control had significantly lower non reducing sugar contents (2.12 % and 2.14 % during 2011 and 2012 respectively) than the remaining treatment combinations. Pooled analyzed data also revealed that fruit non-reducing sugar contents were significantly highest in cultivar Monty under deficit irrigation (3.27 %), and significantly lowest in culti var Hayward under control (2.13 %), among all the treatment combinations Ascorbic acid The data on the fruit ascorbic acid content of different kiwifruit cultivars as affected by two irrigation regimes are presented in Table and Figure It is clear from the data (Table ) that the fruit ascorbic acid content was influenced significantly by different irrigation levels during both the years of study. Ascorbic acid content significantly decreased with the deficit irrigation treatment compared with control. During the year 2011, the average ascorbic acid content in fruits of different cultivars significantly decreased from 85.7 mg/100g under control to 80.9 mg/100g under deficit irrigation. Similarly, ascorbic acid content decreased significantly from 85.5 mg/100g in control to 80.4 mg/100g under deficit irrigation treatment, in the year The pooled data also revealed that the fruit ascorbic acid content decreased significantly following deficit irrigation (80.7 mg/100g) in comparison to control (85.6 mg/100g). The data presented in Table showed that the fruit ascorbic acid content of different cultivars under two water regimes was significantly variable, 172

222 Reduction in ascorbic acid (%) Cultivars Allison Hayward Abbott Monty Bruno Figure Per cent reduction in ascorbic acid content of different cultivars of kiwifruit at irrigation at 60 per cent FC over 80 per cent FC

223 during both the years of study. Fruit ascorbic acid content was found significantly higher in cultivar Bruno (91.0 and 90.8 mg/100g in 2011 and 2012, respectively) in comparison to all other cultivars. However, the ascorbic acid content was observed significantly lowest (76.5 and 76.1 mg/100g in 2011 and 2012, respectively) in fruits of cultivar Allison. Similarly, pooled data revealed that the fruit ascorbic acid content was significantly higher in cultivar Bruno than all other cultivars and significantly least in cultivar Allison. It is revealed from the Figure that the deficit irrigation caused higher per cent decrease in ascorbic acid content in cultivar Hayward (9.77 % ), while the decrease in fruit ascorbic acid content due to deficit irrigation was the least in cultivar Bruno (2.23 %). The interaction effect of cultivars and irrigation levels on fruit ascorbic acid content was also significant. Significantly higher ascorbic acid content was recorded in fruits of cultivar Bruno (92.0 and 91.8 mg/100g at 80 % FC in 2011 and 2012, respectively) under standard irrigation regime than all other treatment combinations. The fruit ascorbic acid content was observed significantly lower in cultivar Allison (74.6 and 73.8 mg/100g in the year 2011 and 2012, respectively) when irrigation was applied at 60 per cent of field capacity in comparison to all other treatment combinations. Similarly, pooled data revealed that ascorbic acid content was significantly higher in cultivar Bruno (91.9 mg/100g) under standard irrigation regime than all other cultivars irrespective of irrigation treatments and significantly least in cultivar Allison (74.2 mg/100g) under condition. deficit irrigation 4.2 EFFECT OF IN SITU MOISTURE CONSERVATION AND DEFICIT IRRIGATION ON GROWTH, WATER RELATIONS AND YIELD OF KIWIFRUIT CULTIVAR ALLISON VEGETATIVE GROWTH Shoot growth The perusal of the data presented in Table revealed that the shoot growth of kiwifruit cultivar Allison was significantly influenced by different levels of irrigation and mulching treatments. In the year 2011, the shoot growth was recorded significantly higher (291.5 cm) in vines given irrigation at 80 per 173

224 cent of field capacity (FC) than those under all other treatments, except the treatment of irrigation at 60 per cent of FC plus black polythene mulching (T 5 ). Significantly shortest shoot extension growth (275.0 cm) was recorded in vines given irrigation at 40 per cent of FC (T 3 ). During the year 2012, the shoot growth was observed significantly higher (290.0cm) under standard irrigation treatment given at 80 per cent of FC (T 1 ) than all other treatments except, T 5 (289.2 cm). However, the vines irrigated at 40 per cent of FC produced shoots with significantly shortest extension growth (274.6 cm). The pooled data also revealed that the average shoot growth of vines irrigated at 80 per cent of field capacity (290.8 cm) was significantly higher than all other treatments except, T 5. However, application of irrigation at 40 per cent of field capacity (T 3 ) resulted in significantly lowest shoot growth (274.8 cm). Table Effect of irrigation levels and mulching on shoot growth (cm) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D Length of internodes The data presented in Table indicate that different treatments of irrigation and mulching had a significant influence on the length of internodes. During the year 2011, the kiwifruit vines subjected to irrigation treatment at 80 per cent of field capacity produced shoots having significantly longer internodes (8.38 cm) in comparison to those under all the remaining treatments except, T 5. During the year 2012, however, the length of internodes was observed longest (8.37 cm) under the treatment T 5 (irrigation at 60 per cent of FC + black polythene mulching) which was however, statistically at par with the treatments T 1 and T 4. The shortest length of shoot internodes (7.86 cm and 7.84 cm in 2011 and 2012, respectively) was noted in the vines irrigated at 40 per cent of FC, 174

225 which was however statistically at par with the vines under the treatments T 6 and T 7, during both the years of study. Table Effect of irrigation levels and mulching on length of internodes (cm) kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D The pooled data revealed that the maximum shoot internodes length (8.37 cm) was observed jointly in vines under the treatments T 1 and T 5, which was significantly higher in comparison to the remaining treatments. The vines irrigated at 40 per cent of field capacity produced shoots with significantly shorter internodes (7.85 cm) in comparison to those under all the remaining treatments except, T Leaf area It is evident from the data presented in Table that different irrigation levels and mulching treatments had a significant influence on average leaf area during both the years of study. During the year 2011, leaves on vines irrigated at 80 per cent of field capacity were significantly larger in area (158.3 cm 2 ) compare to all other treatments except, T 5 (157.6 cm 2 ). In the year 2012, the maximum leaf area was recorded in vines under the treatment T 5, which was statistically at par with treatment T 1, but significantly greater the remaining treatments. The minimum leaf area was observed with irrigation at 40 per cent of FC, during both the years of study (152.0 and cm 2 in 2011 & 2012, respectively). The pooled data revealed that the leaf area was significantly larger under the treatment T 5 in comparison to all the remaining treatments except, T 1 and smaller in vines irrigated at 40 per cent of FC. 175

226 Table Effect of irrigation levels and mulching on leaf area (cm 2 ) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D Leaf thickness The data in Table revealed that different irrigation levels and mulching treatments had a significant influence on leaf thickness of kiwifruit cultivar Allison. During the year 2011, the leaf thickness was recorded significantly higher in the vines irrigated at 40 per cent of field capacity (0.490 mm) in comparison to vines under the remaining treatments except, T 6 and T 7. The minimum leaf thickness (0.410 mm) was recorded in vines irrigated at 80 per cent of field capacity, which was however, statistically at par with the treatments T 2, T 4 and T 5. During the year 2012, the maximum leaf thickness (0.520 mm) was recorded in vines under the treatment T 3, which was however, statistically at par with the T 6, while the minimum leaf thickness (0.410 mm) was recorded in T 5, which was significantly inferior to the remaining treatments except, T 1 and T 4. The pooled data also revealed that the vines irrigated at 40 per cent of field capacity produced leaves having maximum thickness (0.505 mm), which in this regard was statistically at par with the treatment T 6, but significantly superior over the remaining treatments. Conversely, the leaf thickness was found to be minimum (0.411 mm) in T 5, which was however statistically at par with T 1, T 2 and T

227 Table Effect of irrigation levels and mulching on leaf thickness (mm) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D Leaf yellowing It is revealed from the data in the Table that different irrigation and mulching treatments had a significant influence on leaf yellowing of kiwifruit. During the year 2011, the leaf yellowing was recorded significantly higher in vines provided irrigation at 40 per cent of field capacity (46.1 %) in comparison to those under all other treatments. The next higher leaf yellowing percentage was noted under T 6 significantly least (22.5 %) (43.1 %). However, the leaf yellowing was recorded in vines irrigated at 80 per cent of field capacity, followed by those maintained under treatment combination of irrigation at 60 per cent of FC + black polythene mulching (T 5 ). During the year 2012, again the maximum leaf yellowing (48.0 %) was recorded under T 3, followed by T 6 and these treatments significantly differed from each other and from the remaining treatments, in this respect. However, significantly least leaf yellowing (23.0 %) was recorded in vines given irrigation at 80 per cent of field capacity, followed by those under T 5. Table Effect of irrigation and mulching treatments on leaf yellowing (%) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D

228 The pooled further clarified that the irrigation given at 40 per cent of field capacity resulted in significant increase in leaf yellowing percentage over the all other treatments. However, the leaf yellowing was recorded significantly least (22.8 %) when the vines were irrigated at 80 per cent of field capacity. The next superior treatment in this respect was T FLOWERING, FRUIT SET AND FRUIT RETENTION Bloom intensity The perusal of the data presented in Table revealed that during the year 2011, the highest bloom intensity (0.66%) was recorded in vines irrigated at 80 per cent of field capacity, which was however, statistically at par with the vines under the treatment of irrigation at 60 per cent of field capacity + black polythene mulching (T 5 ). Conversely, the bloom intensity was observed significantly lower (0.60 %) under the treatment of irrigation at 40 per cent of field capacity (T 3 ) in comparison to all other treatments except, T 7. During the year 2012, the highest bloom intensity (0.6 4%) was observed jointly under the treatments T 1 and T 5, which was however, statistically at par with the treatment T 7. The bloom intensity was recorded lowest in the T 3 ; however, this treatment did not differ significantly with the treatment T 2, T 4 and T 6, in respect of this attribute. The pooled data also revealed that the bloom intensity was significantly influenced by irrigation treatments. The vines under the treatments T 1 and T 5 recorded significantly higher bloom intensity (0.65 %) over all other treatments. However, the bloom intensity was recorded significantly lower in the treatment T 3 in comparison to all other treatments except, T 6. Table Effect of irrigation levels and mulching on bloom intensity (%) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D

229 Fruit set The data in Table revealed that different irrigation and mulching treatments exerted significant influence on fruit set of kiwifruit cultivar Allison. During the year 2011, the fruit set was recorded significantly higher in vines irrigated at 80 per cent of field capacity (86.7 %) in comparison to all other treatments. The next superior treatments in respect of this attribute were T 5 and T 4 in the decreasing order. The minimum fruit set (78.4 %) was observed in vines irrigated at 40 per cent of field capacity (T 3 ), which was however, statistically at par with the treatment T 6, but significantly inferior to the remaining treatments. During the year 2012, the maximum fruit set (85.6 %) was recorded under the treatment T 1, which was statistically at par with the treatments T 2, T 4 and T 5, while the fruit set was recorded significantly lower in the treatment T 3 (81.5 %) as compared to all the remaining treatments except, T 6. Table Effect of irrigation levels and mulching on fruit set (%) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D The pooled data clearly indicate that fruit set was observed significantly higher in vines irrigated at 80 per cent of field capacity (86.1%) in comparison to those under the remaining treatments. The next higher fruit set percentage was registered under the treatment T 5, followed by T 2. The minimum fruit set (80.0 %) was recorded under the treatment T 3, which was however, statistically at par with the treatment T 6, but inferior to the remaining treatments Fruit retention The data on fruit retention of kiwifruit cv. Allison revealed that the fruit retention was significantly influenced by different levels of irrigation and mulching treatments ( Table 4.2.8). In the year 2011, the highest fruit retention 179

230 (85.5 %) was recorded under the treatment T 1, which was significantly higher than all other treatments. The next superior treatment with respect of this attribute was T 5. The fruit retention was however, observed significantly lowest (65.5 %) under T 3. During the year 2012, the fruit retention was noticed highest (84.4 %) under standard irrigation treatment (T 1 ), which was significantly higher than all other treatments. In this respect, the next superior treatments were T 5 and T 4, in the decreasing order. However, the irrigation given at 40 per cent of FC resulted in minimum fruit retention (70.7 %) on the vines. Table Effect of irrigation levels and mulching on fruit retention (%) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D As per pooled data (Table 4.2.8) the vines irrigated at 80 per cent of field capacity had significantly higher fruit retention (84.9 %) than all other irrigation treatments, which in this respect was followed by the treatment T 5. The fruit retention was however, recorded significantly least (68.1 %) in vines irrigated at 40 per cent of field capacity Fruit yield Total fruit yield The perusal of data presented in Table revealed that during the year 2011, the highest fruit yield (67.0 Kg/vine) was recorded in vines irrigated at 80 per cent of field capacity, which was however, statistically at par with those under the treatment of irrigation at 60 per cent FC + black polythene mulching (66.8 Kg/vine). Conversely, the fruit yield was observed significantly lowest (52.0 Kg/vine) in vines irrigated at 40 per cent of field capacity, followed by those under the treatments T 6 and T 7 in the increasing order. During the year 2012, the highest fruit yield (66.0 Kg/vine) was again observed in the treatment 180

231 T 1, which was significantly higher than all other treatments except, T 5. However, the fruit yield was recorded significantly lower in the treatment T 3 (50.0 Kg/vine) compared to all other treatments. The pooled data further confirmed that the fruit yield was remarkably influenced by irrigation and mulching treatments, which was recorded significantly higher under T 1 (66.5 Kg/vine) in comparison to all other treatments except, T 5. However, the irrigation applied at 40 per cent of FC resulted in significantly lowest fruit yield (51.0 %). Table Effect of irrigation levels and mulching on total fruit yield (Kg/vine) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D Graded fruit yield A Grade fruit yield The data in the Table revealed that different irrigation levels and mulching treatments had significant influence on A grade fruit yield. During the year 2011, the yield under this grade was recorded significantly higher in the treatment T 1 (27.5 % of total yield) in comparison to all other treatments. The second most superior treatment with respect to this attribute was T 5. The production of A grade fruit yield was however, recorded significantly lowest (13.0) under T 3. During the year 2012, the production of A grade fruits was recorded significantly higher under the treatment T 1 (27.0 %) in comparison to all other treatments except, T 5. However, the minimum A grade fruit yield (12.0 %) was recorded under the treatment T 3, which was followed by the treatment T 6. The pooled data depict that significantly higher A grade fruit yield was observed in vines irrigated at 80 per cent of field capacity (27.3 %) in comparison 181

232 to all other treatments. The next superior treatment in this respect was T 5. However, the minimum A grade fruit yield (12.5 %) was recorded in vines irrigated at 40 per cent of field capacity, which was followed by treatment T 6 (irrigation at 40 % FC + mulching with grass). Table Effect of irrigation levels and mulching on yield of A grade fruit (% of total yield) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D B GRADE FRUIT YIELD The data in Table revealed that different irrigation levels and mulching treatments significantly influenced the production of B grade fruits. During the year 2011, the yield under this grade was recorded significantly higher in the treatment T 1 (37.5 % of total yield) in comparison to all other treatments. The second most superior treatment with respect to this attribute was T 5. The production of B grade fruits was recorded significantly lowest (29.8 %) under T 3. During the year 2012, the production of B grade fruits was recorded significantly higher under the treatment T 1 (37.5 %) in comparison to all other treatments except, T 5. However, the minimum B grade fruit yield (30.0 %) was recorded under the treatment T 3, which was however, statistically at par with the treatment T 6. The pooled data depict significantly higher B grade fruit yield in vines irrigated at 80 per cent of field capacity (37.5 %) in comparison to those under rest of the treatments. The next superior treatment in this respect was T 5. However, the minimum B grade fruit yield was recorded under T 3 (29.9 %) which was significantly lowest. however, statistically at par with the treatment T

233 Table Effect of irrigation levels and mulching on yield of B grade fruit (% of total yield) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D C Grade fruit yield The data in Table demonstrate that the production of C grade fruits was significantly influenced by different treatments, during both the years of study. During the year 2011, the yield under this grade was recorded significantly highest in the treatment T 3 (34.0 % of total yield), which was followed by the treatment T 6. However, the production under this grade was recorded significantly lowest under T 1, which was though statistically at par with the treatment T 5. During the year 2012, the production of C grade fruits was recorded significantly higher under the treatment T 3 (33.5 %) in comparison to all other treatments, followed by treatment T 6. However, the minimum C grade fruit yield (25.6 %) was recorded under the treatment T 1, which was followed by the treatment T 5. Table Effect of irrigation levels and mulching on the yield of C grade fruit (% of total yield) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D The pooled data further validated significantly higher C grade fruit yield in vines irrigated at 40 per cent of field capacity (33.8 %) in comparison to 183

234 all other treatments and in respect of this attribute, this treatment was followed by T 6. The production of C grade fruits was registered significantly least (25.8 %) under T 1, followed by the treatment T D Grade fruit yield The data in the Table revealed that different irrigation levels and mulching treatments exerted significant influence on D grade fruit yield. During the year 2011, the yield under this grade was recorded significantly highest in the treatment T 3 (23.2 % of total yield), which was followed by the treatment T 6. The production of D grade fruit yield was recorded significantly lowest under T 1 (9.0 %), followed by the treatment T 5. During the year 2012, the production of D grade fruits was recorded significantly higher under the treatment T 3 (24.5 %) in comparison to all other treatments, which was followed by treatment T 6. However, the minimum D grade fruit yield (9.9 %) was recorded under the treatment T 1, which was however, statistically at par with the treatment, T 5. The pooled data further revealed significantly higher D grade fruit yield in vines irrigated at 40 per cent of field capacity (23.9%) in comparison to those under rest of the treatments. However, the minimum D grade fruit yield was recorded in vines irrigated at 80 per cent of field capacity (9.5 %), followed by those under the treatment T 5. Table Effect of irrigation levels and mulching on yield of D grade fruit (% of total yield) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D

235 4.2.3 SOIL MOISTURE CONTENT AND IRRIGATION FREQUENCY Soil moisture In the present investigation, the soil moisture content fluctuated greatly during the different period of growing season (Figures 4.2.1a, 4.2.1b, 4.2.1c, 4.2.1d, 4.2.2, & 4.2.3; Appendix III), however it varied with different irrigation treatments, in situ moisture conservation techniques and soil depths (Figures 4.2.4, & 4.2.6). In the year 2011, at 30 cm of soil depth greatly higher soil moisture content was recorded in the month of May under T 1, T 4 & T 5 and the least soil moisture contents were observed in T 3 in the month of October (Figure 4.2.1a). During this year, soil moisture content at 60 cm depth was recorded highest soil moisture content in the month of May under T 1 followed by T 5 and T 4 during the same period and the least was observed under T 3 in June (Figure 4.2.1b). During the year 2012, the highest soil moisture content at 30 cm soil depth (20 %) was recorded in the month of May under T 1, followed by T 5 and T 4 in the decreasing order and the least moisture level was observed in October under the vines subjected to T 3 (Figure 4.2.1c). At 60 cm depth, the highest soil moisture content (20.9%) was recorded in the month of May under T 1, followed by T 5 and T 4 and the least was observed under vines subjected to T 3, in the month of June ((Figure 4.2.1d). Soil moisture content (%) Months T1 T2 T3 T4 T5 T6 T7 Figure a Periodic soil moisture contents at 30 cm depth (2011) under the vines of kiwifruit cv. Allison as affected by irrigation and mulching treatments 185

236 Soil moisture content (%) Months T1 T2 T3 T4 T5 T6 T7 Figure b Periodic soil moisture contents at 60 cm depth (2011) under the vines of kiwifruit cv. Allison as affected by irrigation and mulching treatments Soil moisture content (%) Figure c Periodic soil moisture contents at 30 cm depth (2012) under the vines of kiwifruit cv. Allison as affected by irrigation and mulching treatments Soil moisture content (%) Months Months Figure d Periodic soil moisture contents at 60 cm depth (2012) under the vines of kiwifruit cv. Allison as affected by irrigation and mulching treatments T1 T2 T3 T4 T5 T6 T7 T1 T2 T3 T4 T5 T6 T7 186

237 During the year 2011, the average soil moisture content at 30 cm depth was recorded highest under the treatment T 1 (15.3%), followed by T 5 (15.2%) and the least in T 3 (11.0 %), followed by T 6 (11.1%) and T 7 (11.3%). At 60 cm soil depth, the average soil moisture content was found maximum again under T 1 (16.9%) followed by T 5 (16.8%) and the least moisture level was observed under T 3 (12.8%), followed by T 6 and T 7 (Figure 4.2.4). During the year 2012, the average soil moisture content at 30 cm depth was found highest under the vines subjected to treatment, T 1 (14.9 %), followed by those under T 5 (15.0%) while, the least soil moisture level was recorded under T 3 (10.6%), followed by T 6 (10.8%) and T 7 (11.1%). The average soil moisture content at 60 cm depth was found maximum under T 1 (16.4%), followed by T 5 (16.3%) while, the least moisture level was recorded under irrigation at 40 per cent FC (Figure 4.2.5). Soil moisture content (%) cm depth 60 cm depth Months Figure Average soil moisture content (%) of kiwifruit cv. Allison under different irrigation levels and in situ moisture conservation treatments at 30 cm and 60 cm soil depths during the year

238 Soil moisture content (%) cm depth 60 cm depth Months Figure Average soil moisture content (%) of kiwifruit cv. Allison under different irrigation levels and in situ moisture conservation treatments at 30 cm and 60 cm soil depths during the year Year cm 60 cm T1= IR 80% FC T2= IR 60% FC T3= IR 40% FC T4= IR 60% FC +G M T5= IR 60% FC +B M T6= IR 40% FC +G M T7= IR 40% FC +B M A v e ra g e S M C (%) T 1 T 2 T 3 T 4 T 5 T 6 T 7 Treatm ents Figure Effect of in situ moisture conservation and deficit irrigation treatments on soil moisture content (%) at 30 and 60 cm depth in kiwifruit cv. Allison, during

239 20 16 Year cm 60 cm T1= IR 80% FC T2= IR 60% FC T3= IR 40% FC T4= IR 60% FC+GM T5= IR 60% FC+BM T6= IR 40% FC+GM T7= IR 40% FC+BM Average SMC (%) T1 T2 T3 T4 T5 T6 T7 Treatments Figure Effect of in situ moisture conservation and deficit irrigation treatments on soil moisture content (%) at 30 and 60 cm depth in kiwifruit cv. Allison, during cm 60 cm T1= IR 80% FC T2= IR 60% FC T3= IR 40% FC T4= IR 60% FC+GM T5= IR 60% FC+BM T6= IR 40% FC+GM T7= IR 40% FC+BM Average SM C (%) Year 2011 Year T1 T2 T3 T4 T5 T6 T7 Treatments Figure Average soil moisture content (%) under different irrigation levels and in situ moisture conservation treatments in kiwifruit cv. Allison at 30 cm and 60 cm soil depths during the years 2011 and

240 Table Dates of irrigation given to kiwifruit vines under different treatments (2011) Irrigation at 80 % of FC Date of Interval irrigation (days) Irrigation at 60 % FC Date of Interval irrigation (days) Irrigation at 40 % FC Date of Interval irrigation (days) Irrigation at 60%FC + GM Date of Interval irrigation (days) Irrigation at 60% FC+ BM Date of Interval irrigation (days) Irrigation at 40% FC+ GM Date of Interval irrigation (days) Irrigation at 40% FC + BM Date of Interval irrigation (days)

241 Table Dates of irrigation given to kiwifruit vines under different treatments (2012) Irrigation at 80 % of FC Date of Interval irrigation (days) Irrigation at 60 % FC Date of Interval irrigation (days) Irrigation at 40 % FC Date of Interval irrigation (days) Irrigation at 60%FC + GM Date of Interval irrigation (days) Irrigation at 60% FC+ BM Date of Interval irrigation (days) Irrigation at 40% FC+ GM Date of Interval irrigation (days) Irrigation at 40% FC + BM Date of Interval irrigation (days)

242 Frequency and number of irrigations The data pertaining to the frequency and number of irrigations under various levels of irrigation treatments are presented in Tables and It is evident from the data that the irrigation interval fluctuated not only among the treatments but also during different periods of growing season. The minimum irrigation interval was recorded under irrigation treatment applied at 80 per cent of FC between the periods of March 15 to April 5 and later part of October during 2011(7 days) and between March 14 to March 20, during the year 2012(6 days) however, the maximum irrigation interval was registered during monsoon months under the treatment of irrigation at 60% FC + BM (59 days) followed by T 7 during 2011 and T 7 (68 days) and T 6 (66 days) during Irrespective of treatments, it was observed that that the irrigation interval increased gradually with the advancement of growing period in summer, it remained higher during monsoon period and thereafter it declined. The maximum number of irrigations was applied under the irrigation treatment given at 80 per cent of FC (16), followed by irrigation given at 60 per cent of FC (10) and 40 per cent of FC (8) while, the number of irrigation reduced to 7 under irrigation treatment given at 40 per cent FC along with grass and black plastic mulch, during both the years CANOPY TEMPERATURE It is affirmed from the perusal of data on in Table that canopy temperature of kiwifruit vines was significantly influenced by different irrigation levels and mulching treatments. In the year 2011, the highest canopy temperature (30.0 o C) was recorded with the application of irrigation at 40 per cent of field capacity (T 3 ), which was significantly higher than all other treatments. The second highest canopy temperature was observed in the treatment T 2 (29.5 o C). The lowest canopy temperature (27.6 o C) was recorded under T 1, followed by T 5 and T 4 in the increasing order. Similarly in the year 2012, the canopy temperature was recorded significantly higher under T 3 in comparison to all other treatments except, T 2. The lowest canopy temperature (27.5 o C) was noticed under T 1, which was followed by T

243 Table Effect of irrigation levels and mulching on canopy temperature ( o C) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D The pooled data clearly indicate that the vines irrigated at 40 per cent of field capacity had significantly higher canopy temperature (30.1 o C) than those under all other treatments. The lowest canopy temperature (27.6 o C) was however, recorded in vines irrigated at 80 per cent of field capacity (T 1 ), which was followed by T ANATOMICAL AND PHYSIOLOGICAL CHARACTERISTICS AND WATER RELATIONS Stomatal size Stomatal pore length The perusal of the data presented in Table revealed that the stomatal pore length was significantly influenced by different levels of irrigation and mulching treatments. In the year 2011, the maximum stomatal pore length (24.67 µm) was recorded in vines under the treatment T 1, which was however, statistically at par with the treatments T 2, T 4 and T 6. However, the stomatal pore length was registered significantly shorter (24.02 µm) in T 3 than all other treatments except, T 6. During the year 2012, the stomatal pore length was observed significantly higher under T 1 (24.65 µm) than all other treatments except, T 4 and T 5. However, the irrigation given at 40 per cent of FC (T 3 ) resulted in the development of stomatal pores with significantly shortest length (24.06 µm). The pooled data (Table ) show that the vines irrigated at 80 per cent of field capacity had significantly higher leaf stomatal pore length (24.66 µm) in 193

244 comparison to all other treatments except, T 4 and T 5. The stomatal pore length was recorded significantly shortest (24.04 µm) under T 3. Table Effect of irrigation levels and mulching on stomatal pore length (µm) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D Stomatal pore width It is revealed from the perusal of data in Table that the leaf stomatal pore width of kiwifruit vines was significantly influenced by different treatments, in both the years. During the year 2011, the width of leaf stomatal pore was found significantly higher under the treatment T 1 (11.72 µm) in comparison to all other treatments. The next superior treatment in respect of this parameter was T 5. However, the minimum stomatal pore width was recorded in the treatment T 3 (10.15 µm). During the year 2012, again the maximum stomatal pore width kiwifruit (11.71 µm) was recorded in vines irrigated at 80 per cent of field capacity which was significantly higher than all other treatments. In respect to this attribute, the second superior treatment was the T 5. The stomatal pore width was however, noticed significantly least under T 3 (10.14 µm). The pooled data also show significantly higher leaf stomatal pore width in vines irrigated at 80 per cent of field capacity (11.72 µm) in comparison to those under all other treatments. In this respect, the next superior treatment was T 5. However, significantly least width of stomatal pore (10.15 µm) was recorded in vines irrigated at 40 per cent of field capacity. 194

245 Table Effect of irrigation levels and mulching on stomatal pore width (µm) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D Stomatal density The leaf stomatal density was significantly influenced by different levels of irrigation and mulching treatments, during both the years of study (Table ). In the year 2011, the stomatal density was observed to be significantly higher in vines irrigated at 40 per cent of field capacity (8.75 per 0.04 mm 2 ) than those under all other treatments except, T 6. The lowest stomatal density (8.68 per 0.04 mm 2 ) was recorded jointly under T 1 and T 5, which was however statistically at par with the treatments T 2, T 4 and T 7. During the year 2012, the highest stomatal density (8.80 per 0.04 mm 2 ) was found under T 7, which was however, statistically at par with the treatments T 3, and T 6. However, the vines irrigated at 80 per cent of FC had the lowest stomatal density (8.65/ 0.04 mm 2 ), though in respect of this attribute, this treatment was statistically at par with those under the treatments T 4 and T 5. Table Effect of irrigation and mulching treatments on stomatal density (No/ 0.04 mm 2 ) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D The pooled data resolved that the vines irrigated at 80 per cent of field capacity had significantly least stomatal density (8. 67/ 0.04 mm 2 ) in comparison 195

246 to all other treatments except, T 4 and T 5. Conversely, the vines irrigation at 80 per cent of field capacity had highest stomatal density (8. 76/ 0.04 mm 2 ), which was however statistically at par with the treatments T 6 and T Leaf water potential The data presented in Table indicate that irrigation levels and mulching treatments had significant influence on leaf water potential. During the year 2011, leaf water potential was observed significantly least negative (-8.70 bars) in the vines subjected to irrigation treatment at 80 per cent of field capacity (T 1 ), which was followed by the treatments T 5, T 4 and T 2. However, the leaf water potential was recorded significantly more negative in vines irrigated at 40 per cent of field capacity in comparison to all other treatments. During 2012, the leaf water potential was observed significantly least negative (-8.67 bars) under T 1, followed by T 2. However, the vines irrigated at 40 per cent of FC developed significantly more negative leaf water potential (-9.13 bars). Table Effect of irrigation and mulching on leaf water potential (-bars) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D The pooled data also revealed that the vines irrigated at 80 per cent of field capacity (T 1 ) had significantly least negative leaf water potential (-8.69 bars), followed by those under T 5. Conversely, the irrigation at 40 per cent of field capacity (T 3 ) resulted in the development of most negative lower leaf water potential (-9.14 bars) Stomatal resistance The stomatal resistance of kiwifruit vines was affected significantly by different treatments (Table ). During the year 2011, the stomatal resistance 196

247 A B C D Plate 5 Stomatal structure of kiwifruit cultivar Allison under different treatments- irrigation at 80% FC (A), irrigation at 60% FC (B), irrigation at 40 % FC (C), irrigation at 60% FC+ black plastic mulch (D)

248 of kiwifruit vines was recorded significantly higher under the treatment T 3 (4.40 Scm -1 ) in comparison to all other treatments. The next treatment with respect to higher stomatal resistant was T 2. Significantly lowest stomatal resistance was however, recorded in T 1 (4.24 Scm -1 ). During 2012, significantly higher stomatal resistance (4.41 Scm -1 ) was recorded under T 3 in comparison to all other treatments. The stomatal resistance was however, recorded significantly lowest (4.26 Scm -1 ) under T 1. The pooled data also indicate that the stomatal resistance was observed significantly highest under T 3 (4.41 Scm -1 ), followed by the treatment T 2. However, the stomatal resistance was recorded significantly lowest under T 1, followed by the treatments T 5 and T 4, in the increasing order. Table Effect of irrigation and mulching treatments on stomatal resistance (S cm -1 ) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D Transpiration rate The perusal of the data presented in Table revealed that the transpiration rate was influenced significantly by different treatments, during both the years of study. In the year 2011, significantly highest transpiration rate (10.43 m mol m -2 s -1 ) was recorded under the treatment T 1, followed by the treatments T 5 and T 4 in the decreasing order. Significantly lowest transpiration rate (8.10 m mol m -2 s -1 ) was however, recorded under T 3. During the year 2012, again the transpiration rate was observed significantly higher under T 1 comparison to all other treatments. The next higher transpiration rates were observed under T 5 and T 4. However, the irrigation given at 40 per cent of FC decreased the transpiration rate (8.18 m mol m -2 s -1 ) significantly when compared with all other treatments. in 197

249 The pooled data further clarify that the vines irrigated at 80 per cent of field capacity had significantly highest (10.45 m mol m -2 s -1 ) transpiration rate followed by those under the treatments T 5 and T 4. The minimum transpiration rate (8.14 m mol m -2 s -1 ) was recorded in vines irrigated at 40 per cent of field capacity. Table Effect of irrigation and mulching treatments on transpiration rate (m mol m -2 s -1 ) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D Photosynthetic rate The photosynthetic rate of kiwifruit vines varied significantly in response to different treatments (Table ). In the year 2011, the significantly higher photosynthetic rate (19.1 µmol m -2 s -1 ) was recorded in vines given standard irrigation (T 1 ) than those under all other treatments except, T 5. The lowest photosynthetic rate (17.2 µmol m -2 s -1 ) was however, recorded in vines irrigated at 40 per cent of FC. During the year 2012, the photosynthetic rate was observed significantly higher under T 1 (19.0 µmol m -2 s -1 ) than all other treatments except, T 5. However, the photosynthetic rate was decreased significantly with the irrigation treatment given at 40 per cent of FC (17.1 µmol m -2 s -1 ) as compared to all other treatments. The pooled analyzed data also revealed that the vines irrigated at 80 per cent of field capacity had significantly higher photosynthetic rate (19.1 µmol m - 2 s -1 ) than those under all other treatments except, T 5. Conversely, the rate of photosynthesis was recorded significantly lowest (17.2 µmol m -2 s -1 ) under T

250 Table Effect of irrigation and mulching treatments on photosynthetic rate (µ mol m -2 s -1 ) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D Chlorophyll content It is evident from the data (Table ) that the leaf chlorophyll content of kiwifruit was significantly influenced by different irrigation and mulching treatments. During the year 2011, the leaf chlorophyll content was recorded significantly highest (3.14 mg/g) in vines subjected to standard irrigation treatment (T 1 ) followed by those under the treatment T 5. Whereas, leaf chlorophyll content was observed significantly least (2.30 mg/g) in vines irrigated at 40 per cent of FC. In the year 2012, again the leaf chlorophyll content found significantly higher under T 1 (3.12 mg/g) in comparison to all other treatments. The next superior treatment in respect of this attribute was T 5. However, the vines irrigated at 40 per cent of FC (T 3 ) had leaves with lowest chlorophyll content (2.29 mg/g). The pooled data further validated that the vines under standard irrigation practice registered significantly highest leaf chlorophyll content (3.13 mg/g), followed by the treatment T 5. Further, the lowest leaf chlorophyll content was noted in vines irrigated at 40 per cent of FC (2.30 mg/g). Table Effect of irrigation and mulching treatments on leaf chlorophyll content (mg/g) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D

251 Chlorophyll stability index The data presented in Table indicate that the leaf chlorophyll stability index (CSI) of kiwifruit was significantly influenced by different irrigation and mulching treatments. During the year 2011, significantly greatest chlorophyll stability index (66.9 %) was noted in vines under T 3, followed by those under T 6 and T 7, in the decreasing order. However, the CSI was recorded significantly least (47.3 %) under T 1. During the year 2012, again significantly higher CSI (68.1 %) was observed in vines grown under the treatment T 3, in comparison to those under all other treatments. The vines under standard irrigation (T 1 ) however, registered significantly least CSI (48.1 %). The pooled data further confirmed that T 3 was the most superior treatment with respect to leaf CSI (67.5 %), followed by T 6. However, the vines under T 1 was most inferior in respect of this attribute (47.7% CSI). Table Effect of deficit irrigation and mulching on CSI (%) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D Proline content The leaf proline content of kiwifruit was significantly influenced by different irrigation and mulching treatments (Table ). During the year 2011, the leaf proline content was detected significantly higher in vines under T 3 ( µg/g) than those under all other treatments. The next superior treatment in this respect was T 6. However, the minimum proline content ( µg/g) was observed in vines under standard irrigation (T 1 ), which was however, statistically at par with T 5. During the year 2012, again significantly higher proline content was observed in vines under T 3 ( µg/g) in comparison to those under the 200

252 remaining treatments except, T 6 and T 2. Conversely, the vines under the treatment T 1 registered significantly lowest ( µg/g) leaf proline content. The pooled data also revealed that the irrigation applied at 40 per cent of FC resulted in significantly highest accumulation of proline in leaves ( µg/g), which was followed the treatment, T 6. However, the leaf proline content was observed significantly lower in vines irrigated at 80 per cent of FC ( µg/g) in comparison to those under all other treatment. Table Effect of irrigation and mulching treatments on leaf proline content (µg/g fresh weight basis) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D Free amino acids The data on free amino acid content of kiwifruit cv. Allison as affected by different treatments are presented in Table It is evident from the data that the levels free amino acids in leaves were significantly influenced by different irrigation and mulching treatments. During the year 2011, the accumulation of free amino acid content was recorded highest (72.0 mg/g) in vines irrigated at 40 per cent of field capacity, followed by those under the treatment T 6, however, the level of free amino acids was observed significantly lowest (57.2 mg/g) in vines under the treatment T 1. During the year 2012, the concentration of free amino acid was again observed significantly higher in leaves under the treatment T 3 (71.0 mg/g), in comparison to all other treatments except, T 6. However, the accumulation of free amino acid content was noticed significantly lesser (56.4 mg/g) under the treatment T 1 in comparison to rest of the treatments except, T

253 The pooled analyzed data also revealed that the irrigation applied at 40 per cent of FC increased the free amino acid content of leaves to the highest level (71.5 mg/g), which in this respect was followed by the treatment T 6. The lowest concentration free amino acid (56.8 mg/g) was however, statistically at par with T 5. found under T 1, which was Table Effect of irrigation and mulching treatments on free amino acids (mg/g fresh weight basis) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D Relative water content The data in Table revealed that the relative water content (RWC) of kiwifruit vines was significantly influenced by different levels of irrigation and mulching treatments. In the year 2011, significantly higher RWC (88.0 %) was recorded in vines under T 1 than those under all other treatments. The next superior treatment with regard to this parameter was T 5. The RWC was however, recorded significantly lowest (56.1 %) under T 3. During the year 2012, the RWC was observed highest (87.2 %) again under standard irrigation treatment than all other treatments. In respect to this attribute, the next superior treatment was T 5. However, the RWC was observed significantly least (55.3 %) in vines irrigated at 40 per cent of FC. It is evident from the pooled data that the vines irrigated at 80 per cent of field capacity had significantly higher RWC (87.6 %) than all other treatments, which was followed by the treatment T 5. However, significantly lowest RWC (55.7 %) was recorded in vines irrigated at 40 per cent of field capacity. 202

254 Table Effect of irrigation and mulching treatments on RWC (%) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D Xylem development Number of primary xylem vessels The data in the Table revealed that different treatments exerted a significant influence on development of primary xylem vessels in kiwifruit. During the year 2011, the number of primary xylem was recorded significantly higher in vines irrigated at 80 per cent of field capacity (92.0) in comparison to those under all other treatments except, T 5. The minimum number of primary xylem (81.0) was counted in vines irrigated at 40 per cent of field capacity (T 3 ), which in this respect was however, statistically at par with the treatment T 6, but significantly inferior to the remaining treatments. During the year 2012, the maximum number of primary xylem (93.0) was recorded under the treatment T 1, which was significantly higher in comparison to all other treatments. The next Table Effect of irrigation and mulching treatments on the number of primary xylem in kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D

255 superior treatments in respect of this attribute were T 5 and T 4 in the decreasing order. However, the number of primary xylem was recorded significantly lower in the treatment T 3 (80.0) as compared to all the remaining treatments, followed by the treatment T 6. The pooled data again clarified that the number of primary xylem was observed significantly higher in vines irrigated at 80 per cent of field capacity (92.5) in comparison to those under the remaining treatments. The next higher number of primary xylem was registered under the treatment T 5, followed by T 4. However, the minimum number of primary xylem (80.5) was recorded under the treatment T 3, followed by the treatment T Length of secondary xylem vessels The data in Table revealed that different irrigation and mulching treatments had a significant influence on the development of secondary xylem vessels of kiwifruit. During the year 2011, the length of secondary xylem was recorded significantly higher in vines irrigated at 80 per cent of field capacity (166.0 µm) in comparison to all other treatments except, T 5. The length of secondary xylem was measured least (154.0 µm) in vines irrigated at 40 per cent of field capacity (T 3 ), which was however, statistically at par with the treatments T 2, T 6 and T 7, but significantly inferior to the remaining treatments. During the year 2012, the length of secondary xylem was recorded significantly more (164.0 µm) under the treatment T 1 in comparison to all other treatments except, T 5. However, the length of secondary xylem was recorded significantly shorter in the treatment T 3 (152.0 µm) as compared to all the remaining treatments except, T 2. Table Effect of irrigation and mulching treatments on length of secondary xylem (µm) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D

256 A B C D E F G Plate 6 Xylem vessel development in kiwifruit cv. Allison under - irrigation at 80% FC (A), irrigation at 60% FC (B), irrigation at 40 % FC (C), irrigation at 60% FC+ grass mulch (D), irrigation at 60% FC+ black plastic mulch (E), irrigation at 40 % FC+ grass mulch (F) and irrigation at 40 % FC + black plastic mulch (G)

257 The pooled data clearly indicate that length of secondary xylem was observed significantly higher in vines irrigated at 80 per cent of field capacity (165.0 µm) in comparison to those under the remaining treatments. The next superior treatment in respect of this attribute was T 5. However, the minimum length of secondary xylem (153.0 µm) was recorded under the treatment T 3, which was however, statistically at par with the treatment T Endogenous hormones Cytokinin content The cytokinin content of kiwifruit vine was significantly influenced by different irrigation and mulching treatments (Table ). During the year, 2011 the cytokinin content was recorded significantly higher in vines irrigation at 80 per cent of field capacity (72.0 ρg/g) in comparison to those under rest of the treatments. The next superior treatments in respect of this attribute were T 5 and T 4, in the decreasing order. The cytokinin content was observed lowest (55.5 mg/g) in vines irrigated applied at 40 per cent of FC (T 3 ). In the year 2012, again the level of cytokinin also observed significantly highest under T 1 (71.0 ρg/g), followed by T 5. On the contrary, the irrigation treatment when applied at 40 per cent of FC decreased the cytokinin content to the lowest level (55.0 ρg/g). The pooled data also revealed that the vines maintained under standard irrigation practice (T1) had significantly highest cytokinin content (71.5 ρg/g), which followed by those under the treatment T 5. The level of cytokinin content was observed significantly least (55.3 ρg/g) in the vines under T 3. Table Effect of irrigation levels and mulching treatments on cytokinin (ZR ρg/g fresh weight basis) content of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D

258 Abscisic acid It is evident from the data presented in Table that the abscisic acid content of kiwifruit was significantly influenced by different irrigation and mulching treatments. During the year 2011, significantly higher ABA level was observed in vines under T 3 (49.2 ηg/g) as compared to all other treatments. The next higher ABA level was detected in vines under the treatment T 6. However, the ABA content was observed to be least in vines given irrigation at 80 per cent of FC (34.8 ηg/g), which was however, statistically at par with the treatment T 5. During the year 2012, significantly highest ABA content was also observed again under T 3 (50.0 ηg/g), which was followed by the treatments T 2 and T 6 in the decreasing order. The irrigation treatment when applied at 80 per cent of FC, however, decreased the accumulation of ABA to the significantly lowest level (36.0 ηg/g). The pooled further clarified that the irrigation applied at 40 per cent of FC increased the ABA content to a significantly higher level (49.6 ηg/g) over rest of the treatments. The next higher ABA content was noted under T 6 (46.9 ηg/g). Significantly least ABA content was found under the treatment T 1, followed by T 5. Table Effect of irrigation levels and mulching treatments on ABA (ηg/g fresh weight basis) content of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D Leaf nutrient status Nitrogen The perusal of the data presented in Table revealed that the leaf nitrogen content of kiwifruit vines varied significantly under different treatments. 206

259 In the year 2011, significantly higher leaf nitrogen contents were recorded in vines under the treatments T 1, T 4 and T 5 in comparison to rest of the treatments. Significantly lower leaf nitrogen content (2.01 %) was recorded in vines irrigated at 40 per cent of FC (T 3 ) in comparison to those under rest of the treatments except, T 6. During the year 2012, the leaf nitrogen content was recorded significantly highest under T 1, closely followed by the treatments T 5, T 4 and T 2 in the decreasing order. Conversely, the vines given irrigation at 40 per cent of FC had significantly least leaf nitrogen content (2.00 %). The pooled data showed that the vines irrigated at 80 per cent of field capacity had significantly highest leaf nitrogen content (2.17 %), followed by the vines under T 5 and T 4 in the decreasing order. However, the concentration of leaf nitrogen was recorded significantly least (2.01 %) in vines irrigated at 40 per cent of field capacity. Table Effect of irrigation and mulching treatments on leaf nitrogen content (%) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D Phosphorus The data on the influence of different irrigation and mulching treatments on leaf phosphorus content of kiwifruit vines have been displayed in Table It is apparent from the perusal of data that the leaf phosphorus content was significantly influenced by different treatments during both the years of study. In the year 2011, the highest phosphorus content (0.17%) was recorded in vines under the treatment T 1, which was however, statistically at par with the treatments T 5 and T 4. The minimum leaf phosphorus content (0. 10 %) was recorded under the treatment T 3, which was however, statistically at par with the 207

260 treatments T 2, T 6 and T 7. During the year 2012, leaf phosphorus content was found significantly more under treatment T 1 in comparison to all other treatments except, T 5. However, the irrigation given at 40 per cent of FC (T 3 ) resulted in minimum accumulation of phosphorus in leaves (0.09 %), which was however, statistically at par with the treatments T 6 and T 7. The pooled data also revealed that the vines irrigated at 80 per cent of field capacity had significantly higher leaf phosphorus content (0.18 %) than those under all other irrigation treatments except, T 5. The minimum leaf phosphorus content (0.10 %) was recorded in vines irrigated at 40 per cent of field capacity, which was however, statistically at par with vines under the treatments T 6 and T 7. Table Effect of irrigation and mulching treatments on leaf phosphorus content (%) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D Potassium The perusal of the data presented in Table revealed that the leaf potassium content was influenced significantly by different levels of irrigation and mulching treatments. In the year 2011, leaf potassium content was recorded significantly higher under the treatment T 1 (2.45%) in comparison to all the remaining treatments except, T 5. Conversely, leaf potassium content was recorded significantly lower under T 3 (2.43%) in comparison to all other treatments except, T 6. During the year 2012, the potassium content was noted significantly highest again under T 1 (2.43 %) than all other treatments except, T 5. However, the irrigation given at 40 per cent of FC (T 3 ) resulted in significantly 208

261 lesser accumulation of potassium (2.27 %) in leaves in comparison to all other treatments except, T 6. Table Effect of irrigation and mulching treatments on leaf potassium content (%) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D The pooled data also revealed that the vines irrigated at 80 per cent of field capacity had significantly higher leaf potassium content (2.44 %) than those under all the remaining treatments except, T 5. The minimum potassium content (2.28 %) was recorded under T 3, which was however, statistically at par with T 6 (2.31%) Calcium The data presented in Table indicate that different treatments of irrigation and mulching significantly influenced the leaf calcium level of kiwifruit. In the year 2011, the kiwifruit vines exhibited highest leaf calcium content when subjected to irrigation treatment at 80 per cent of field capacity (3.90 %), which was however, statistically at par with the treatments T 4 and T 5. The minimum calcium content was observed in vines irrigated at 40 per cent of FC (3.60 %), which in respect of this parameter, were statistically at par with those under the treatment T 6. During the year 2012, again significantly highest calcium content (3.91 %) was observed under the treatment T 1 followed by the treatments T 5 and T 4, in the decreasing order. The minimum calcium content (3.59 %) was observed in vines irrigated at 40 per cent of FC, which was however, statistically at par with those maintained under the combined treatment irrigation at 40 per cent of FC + grass mulching (3.61 %). 209

262 Table Effect of irrigation and mulching treatments on leaf calcium content (%) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D The pooled data also revealed that the vines irrigated at 80 per cent of field capacity had maximum leaf calcium content (3.91 %), which was however, statistically at par with those under the treatment T 5. On the contrary, the vines irrigated at 40 per cent of field capacity produced leaves with lowest calcium content (3.60 %), which were however, statistically at par with those under the treatment T 6, in this respect Magnesium It is evident from the data presented in Table that the leaf magnesium content was significantly influenced by different levels of irrigation and mulching treatments. In the year 2011, the leaf magnesium content was recorded significantly higher in vines under T 1 (0.37 %), which was however, statistically at par with the treatments T 4 and T 5. The lowest magnesium content (0.28 %) was recorded in vines irrigated at 40 per cent of FC (T 3 ), which was however, statistically at par with T 6. During the year 2012, leaf magnesium content was found significantly higher under T 1 (0.38 %) in comparison to rest of the treatments except, T 4 and T 5. However, the treatment of irrigation given at 40 per cent of FC (T 3 ) resulted in lowest accumulation of magnesium in leaves (0.29 %), which in this respect was significantly inferior to all other treatments except, T 6. The pooled data further established that the vines irrigated at 80 per cent of field capacity (T 1 ) had significantly higher leaf magnesium content (0.38 %) than those under all other remaining treatments except, T 5. The minimum leaf 210

263 magnesium content (0.29 %) was recorded in vines irrigated at 40 per cent of field capacity, which was however, statistically at par with those under T 6. Table Effect of irrigation and mulching treatments on leaf magnesium content (%) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D FRUIT QUALITY Fruit size and weight Fruit length Average fruit length of kiwifruit cultivar Allison was significantly influenced by different treatments during the course of study (Table ). During the year 2011, the kiwifruit vines when subjected to irrigation treatment at 80 per cent of field capacity produced fruit having significantly higher length (78.7 mm) in comparison to those under all the remaining treatments. Conversely, significantly shortest fruit length (60.3 mm) was observed in vines irrigated at 40 per cent of field capacity, followed by those under the treatments T 6 and T 7. During the year 2012, the fruit length was recorded significantly more under T 1 (78.2 mm) as compared with all other treatments except T 5, while the fruit length was observed significantly shortest under the treatment T 3 (60.2 mm), followed by T 6 and T 7 in the increasing order. The pooled data clearly indicate that the vines irrigated at 80 per cent of field capacity produced fruits with highest length (78.5 mm) in comparison to those under the remaining irrigation and mulching treatments, followed by the treatments T 5 and T 4 in the decreasing order. Conversely, the vines under the treatment T 3 registered the shortest fruits length (60.3 mm), followed by T 6 and T 7 treatments in the increasing order. 211

264 Table Effect of irrigation and mulching treatments on fruit length (mm) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D Fruit diameter Fruit dimension in terms of diameter was also significantly influenced by different irrigation and mulching treatments (Table ). During the year 2011, significantly higher fruit diameter was noted in the vines subjected to irrigation at 80 per cent of field capacity (45.5 mm) in comparison to all other treatments except, T 5 and T 4. However, the vines under T 3 treatment produced fruits with minimum diameter (37.5 mm), which in respect of this attribute was however, statistically at par with those under the treatments T 6 and T 7. During the year 2012, the fruit diameter was observed significantly higher under T 1 (45.0 mm) compared with all other treatments except, T 4 and T 5. However, the minimum fruit diameter was recorded in vines under T 3 statistically at par with T 6. (37.4 mm), which was however, Table Effect of irrigation and mulching treatments on fruit diameter (mm) of kiwifruit cv. Allison Treatments Pooled T 1 : Irrigation at 80% of FC T 2 :Irrigation at 60% of FC T 3 :Irrigation at 40% of FC T 4 :Irrigation at 60% of FC + Mulching with grass T 5 :Irrigation at 60% of FC + Black polythene mulching T 6 :Irrigation at 40% of FC + Mulching with grass T 7 :Irrigation at 40% of FC + Black polythene mulching C D It is also evident from the pooled data that the fruit diameter was observed significantly higher under T 1 (45.3 mm) than all other treatments except, T 5 and 212

265 Plate 7 Effect of different irrigation levels on size of kiwifruit cv. Allison