SEED GERMINATION STUDIES IN PAPAYA (Carica papaya L.)

Transcription

1 SEED GERMINATION STUDIES IN PAPAYA (Carica papaya L.) PADMA LAY PAK 9271 DEPARTMENT OF SEED SCIENCE AND TECHNOLOGY UNIVERSITY OF AGRICULTURAL SCIENCES GKVK, BENGALURU

2 SEED GERMINATION STUDIES IN PAPAYA (Carica papaya L.) PADMA LAY PAK 9271 Thesis submitted to the University of Agricultural Sciences, Bengaluru in partial fulfillment of the requirements for the award of the degree of Master of Science (Agriculture) in SEED SCIENCE AND TECHNOLOGY BENGALURU AUGUST, 2011

3 Affectionately dedicated to my Abalay,Amalay and family

4 DEPARTMENT OF SEED SCIENCE AND TECHNOLOGY UNIVERSITY OF AGRICULTURAL SCIENCES BENGALURU CERTIFICATE This is to certify that the thesis entitled Seed germination studies in papaya ( Carica papaya L.) submitted by Ms. Padma Lay ID No. PAK 9271, for the award of degree of MASTER OF SCIENCE (Agriculture) in SEED SCIENCE AND TECHNOLOGY of the University of Agricultural Sciences, Bengaluru, is a record of the research work carried out by her during the period of her study in this University, under my guidance and supervision and no part of the thesis has been submitted for the award of any other degree, diploma, associateship, fellowship or other similar titles. Bengaluru August, 2011 Dr. G.V. Basavaraju Professor and former head Approved by: Chairman: (G.V. BASAVARAJU) Members: (K.R. SREERAMULU) (B.C. CHANNAKESHAVA) (R. PARAMESH) (H.S. YOGEESHA)

5 ACKNOWLEDGEMENT Gratitude takes three forms A feeling from heart, an expression in words and a giving in return, I sincerely thank all those who directly made this thesis possible. First of all I would thank God Almighty for His grace and mercy which made it possible for me to complete this present venture. It is my privilege to express my deepest sense of gratitude and indebtedness to my Major Advisor and Chairman of Advisory Committee Dr. G.V. Basavaraju Professor and former head, Department of Seed Science and Technology, University of Agricultural Sciences, Bengaluru for his interest, enthusiasm, innovative suggestions and dynamic guidance during the period of research and preparation of manuscript. I am extremely grateful to the members of my Advisory Committee Dr. K.R. Sriramulu, Professor and Head, Department of Agricultural Microbiology, University of Agricultural Sciences, Bengaluru, Dr. B.C. Channakeshava, Professor and Head, Department of Seed Science and Technology, University of Agricultural Sciences, Bengaluru, Mr. R. Paramesh, Associate Professor,Department of Seed Science and Technology, University of Agricultural Sciences, Bengaluru and Dr. H.S. Yogeesha, Principal Scientist, IIHR, Hessaraghatta, Bengaluru who have kindly rendered their cooperation, encouragement and suggestions throughout my course of investigation. With sense of pride and dignity, I would sincerely thank my respected teachers Dr. Ramegowda, Professor, Dr. K.P.R. Prasanna, Professor & Dean (SW), Dr. Balakrishna, Professor, Dr. P. J. Devaraju, Associate Professor, Department of Seed Science and Technology, for their generous assistance and support during my study. I bestow my genuine thanks to all the supporting staff of the department, Mr. Urs, for his generous help during my course of study. I also wish to thank Smt. Kamalamma, for her liberal assistance during my course of study.

6 I am personally thankful to Mr. Somashekar, SMS, KVK, IIHR, Hirehalli and Mr. Manjunath, Farm Manager, KVK, Hirehalli for their help and support during my work. My gratitude also goes to Mr. Mallikarjuna, Associate Professors Department of Statistics, UAS, GKVK, Bengaluru. I avail this unique opportunity to express my heartfelt gratitude with regards to Dr. Zahoor Ahmed Dhar Asst Professor genetics and plant breeding of SKAUST- K,Shalimar for extending their help either directly or indirectly throughout my study. I express my gratitude towards ICAR for giving me seat in this University. My parents Sri Nawang Chotak, Smt. Disket Yangdol, aspiration was my source of inspiration. As a token of love, I dedicate this manuscript to them. My deep sense of love and gratitude also goes to my brothers Tsering Phuntsog, Stanzin Dorjey, Chamba Skalzang, sisters Cho Cho Zangmo, Chamba Lhamo and other family members whose affectionate blessing and worthy counsel gave me a sense of warm impetus beyond the academic scene. Without their help, cooperation and understanding throughout, the ambition of completing this task would not have been fulfilled. Not to forget that without my friends Spaldon, Gowri, Vrushali, Baphi, Soubhagya, Rohith, Dawa, Donal, Hema, Pankaj, Gavi, Maruthi, Ravi, Sangmesh this endeavour would have seemed longer. I sincerely thank them for their timeless support and help. I also would like to thank my seniors Nagaraju sir, Reddy sir and Nataraj sir for their suggestions and encouragement and last but not the least I would like to thank my juniors. Any omission in this brief acknowledgement does not mean lack of gratitude. Bengaluru August, 2011 (Padma Lay)

7 SEED GERMINATION STUDIES IN PAPAYA (Carica papaya L.) PADMA LAY ABSTRACT A study was carried out to know the optimum fruit maturity stages, ideal temperature and media, dormancy breaking methods on seed quality parameters of papaya (Carica papaya L.) cv. Surya. Seeds extracted from fruits harvested at 1/4 th, 1/2, 3/4 th and Complete yellow/orange and after ripening were subjected to germination after removal of sarcotesta at different temperature (20, 25, 30, 35, 20-30, and C) and at different media (BP, TP, Sand and Coir pith). Seeds from full mature fruits were subjected for dormancy breaking treatments by using GA 3, KNO different concentrations and durations, Hot water 50 C and Azotobacter 5g/kg seed at different durations. The results revealed that seeds extracted from freshly harvested complete yellow/orange and 1/4 th yellow/orange fruits subjected to after ripening recorded higher germination (52.50 and 94.00%), TDH activity ( and 1.204), lower EC ( and 0.131) and higher field emergence (48.0 and 72.00%) respectively C alternate temperature, Sand and BP media recorded higher germination (89.00, and 81.20%), speed of germination (48.56, and 27.52) respectively. Among dormancy breaking treatments higher germination was recorded in 300ppm for 12 h and KNO 2% for 24 h (93.00 and 91.00% respectively). Bio inoculation of Azotobacter chrococcum for 20 days and Hot water 50 C for 45 min recorded maximum germination respectively ( and 78.00%), SVI (1387 and 969) field emergence (81.30 and 59.33%). Thus, Seed extraction from complete yellow/orange fruits, GA 3, KNO 3 and Azotobacter chrococcum treatments can enhance the germination and other seed quality parameters in papaya ( Carica papaya L.) cv. Surya. Department of Seed Science and Technology, University of Agriculture Sciences G.K.V.K., Banglore-65 Dr. G.V.BASAVARAJU Major Advisor

8 ÀgÀAV Ãd ªÉƼÀ«PÉAiÀÄ CzsÀåAiÀÄ À ÀzÀä Éà ÀgÁA±À F CzsÀåAiÀÄ ÀªÀ ÀÄß ÀgÀAV ºÀtÄÚ ÄAiÀÄÄ«PÉAiÀÄ ºÀAvÀ, CzÀ±Àð vá ÀªÀiÁ À ªÀÄvÀÄÛ ªÀÄzsÀåªÀiÁ, Ãd ÀÄ ÁÛªÀ ÉÜ ºÉÆgÀºÁPÀĪÀ «zsá ÀªÀ ÀÄß ÃdUÀÄtzsÀªÀÄðUÀ¼À è CzsÀåAiÀÄ À ªÀiÁqÀ ÁVzÉ. ÀÆAiÀÄðvÀ½AiÀÄ è Ãd ÀA±ÀÌgÀtªÀ ÀÄß ««zsà ºÀtÄÚ Ä«PÉAiÀÄ ºÀAvÀzÀ è (1/4, 1/2, 3/4 Éà ªÀÄvÀÄÛ Àj ÀÆtð ºÀ¼À /QvÀÛ¼É tú AzÀ PÀÆrzÀ ºÁUÀÆ ÀAvÀgÀ ºÀtÄÚ qàäªà ºÀAvÀzÀ è Ãd ÀA ÀÌgÀuÉ ªÀiÁr Ãd ªÉƼÀ«PÉAiÀÄ ÀÄß zàpàð mé ÀÖ véuézà ºÁQzÀ ÀAvÀgÀ ««zsà GµÁÚA±À (20,25,30,35,20-30,20-35 ºÁUÀÆ ÉÃ), ««zsà ªÀiÁzsÀåªÀÄUÀ¼À è (ªÀÄzsÀå Éà Àgï, ªÉÄà À Éà Àgï; ªÀÄgÀ¼ÀÄ ªÀÄvÀÄÛ PÁAiÀÄð À è G ÀZÁgÀzÀ è Ãd ªÉÆüÀ«PÉAiÀÄ ÀÄß zár À ÁVzÉ, ÀA ÀÆtð zà ºÀtÄÚUÀ¼À ÀÄß PÉÆAiÀÄÄèªÀiÁr CªÀÅUÀ¼À ÀÄß ««zsà Ãd ÀÄ ÁÛªÀ ÉÛ ºÉÆgÀºÁPÀĪÀ «zsá ÀªÀ ÀÄß (eé æ Pï CªÀÄè záæªàt, ÉÊnæPï CªÀÄè záæªàtªà ÀÄß ««zsà, PÁ ªÀjAiÀÄ è ºÁUÀÆ 50 Éà GµÀÚA±ÀzÀ è PÁ ĹzÀ Ãj AzÀ ªÀÄvÀÄÛ CdmÉÆà ÁåPÀÖgï 5UÁæA Àæw PÉÃfUÉ. F G ÀZÁgÀ AzÀ PÀAqÀÄ AzÀ sà váa±àªéazàgé. QvÀÛ É/ºÀ¼À tú AzÀ PÀÆrzÀ ÀA ÀÆtð ºÀtÚUÀ¼À ÀÄß PÉÆAiÀÄèªÀiÁrzÀ ºÀtÄÚUÀ¼À è Ãd ÀA ÀÌgÀuÉ ªÀiÁr C üpà Ãd ªÉƼÀªÀ½PÉAiÀÄ ÀæªÀiÁt (52.50 ªÀÄvÀÄÛ 94.00) MlÄÖ qéêºéêqéææãeé À ï ZÀlĪÀwPÉ (1.204) ªÀÄvÀÄÛ PÀrªÉÄ «zsàäåvï ÀAºÀzÀðvÉ (0.10 ªÀÄvÀÄÛ (0.131) C üpà PÉëÃvÀæ Ãd ªÉƼÀ«PÉAiÀÄ ÀæªÀiÁt (48 ªÀÄvÀÄÛ 72.0) zár À ÁVzÉ. ÀAiÀiÁðAiÀÄ GµÁÚA±À (25-30 É.), ªÀÄgÀ¼ÀÄ ªÀÄvÀÄÛ ªÀÄzsÀå Éà Àgï Ãd ªÉÆüÀªÀ½PÉAiÀÄ (89.00, ªÀÄvÀÄÛ 81.20), ªÉƼÀªÀ½ÃPÉAiÀÄ ªÉÃUÀ (45.56, ºÁUÀÆ 27.52) zár À ÁVzÉ. Ãd ÀÄ ÀÛªÀå ÉÜAiÀÄ «zsà ÀzÀ è- f æ Pï CªÀÄè záætªà ÀÄß ÀĪÀiÁgÀÄ 12UÀAmÉ PÁ ªÀ AiÀÄ è É À¹ ªÀÄvÀÄÛ ÉÊnæPï CªÀÄè ±ÉÃ. 2 ÀÄß ÃeÉÆà ÀZÁgÀ ªÀiÁrzÀ è C üpà Ãd ªÉƼÀªÀ½PÉAiÀÄ ÀæªÀiÁt (93.00 ªÀÄvÀÄÛ 91.00) zár À ÁVzÉ. CzÉà jãw eéê«pà G ÀPÀå ìªàä CdÄqÀ ÁåPÀÖgï PÀÆgÀPÁgÁªÀÄ 20 Éà ÃeÉÆà ÀZÁgÀ ªÀiÁr ªÀÄvÀÄÛ 50 Éà GµÀÚ±ÀA±À AzÀ ÀĪÀiÁgÀÄ 45 «ÄµÀ É À ÀĪÀÅzÀjAzÀ C üpà Ãd ªÉƼÀªÀ½ÃPÉAiÀÄ (92.50 ªÀÄvÀÄÛ 78), À¹ ÀvÀé ÀÄa (1387 ªÀÄvÀÄÛ 969) ±ÉÃPÀqÀ PÉëÃvÀæ ªÉƼÀªÀ½PÉ (81.30 ªÀÄvÀÄÛ 59.33) ÀÄß zár À ÁVzÉ. F CzsÀåAiÀÄ À AzÀ w½zàä AzÀ sà váa±àªéazàgé ºÀ¼À /QvÀÛ¼É tzàtzà ºÀtÄÚUÀ¼À ÀÄß PÉÆAiÀÄÄèªÀiÁr CªÀÅUÀ¼À ÀÄß Ãd ÀA ÀÌgÀuÉ ªÀiÁr CªÀÅUÀ¼À ÀÄß ««zsà ÃeÉÆà ÀZÁgÀ (eé æ Pï CªÀÄè, ÉÊnæPï CªÀÄè, ù j AzÀ G ÀZÁgÀ ªÀiÁqÀĪÀÅzÀjAzÀ Ãd ÀÄ ÁÛªÀ ÉÜ ºÉÆgÀºÁPÀĪÀÅzÀ èzé GvÀÛªÀÄ Ãd ªÉÆà ªÀ½PÉAiÀÄ ÀæªÀiÁt ªÀÄvÀÄÛ EvÀvÉ Ãd UÀÄtzÀªÀÄðUÀ¼À ÀÄß ºÉaÑ À ºÀÄzÁVzÉ. DUÀ ïö, 2011 Ãd «eáõ À ªÀÄvÀÄÛ vàavàæeáõ À «sáuà PÀÈ «±Àé«zÁå AiÀÄ f.pé.«.pé. ÉAUÀ¼ÀÆgÀÄ-65 qá. f.«. ÀªÀgÁdÄ ÀæªÀÄÄR À ºÉUÁgÀgÀÄ

9 CONTENTS CHAPTER TITLE PAGE No. I INTRODUCTION 1 3 II REVIEW OF LITERATURE 4 22 III MATERIAL AND METHODS IV EXPERIMENTAL RESULTS V DISCUSSION VI SUMMARY VII REFERENCES

10 LIST OF TABLES Table No (a) 8(b) 9 10(a) Title Influence of stage of fruit maturity on fresh fruit weight (g), fresh Seed weight (g) with sarcotesta, fresh seed weight (g) without sarcotesta, and seed recovery (%) in papaya (Carica papaya L.) Influence of stage of fruit maturity on seed index (g), seed moisture (%), germination (%) and fresh ungerminated seeds (%) in papaya (Carica papaya L.) Influence of stage of fruit maturity on seedling length (cm), seedling dry weight (mg), seedling vigour index-i and seedling vigour index II in papaya (Carica papaya L.). Influence of stage of fruit maturity on EC (µscm -1 ), TDH (A480) and field emergence (%) in papaya (Carica papaya L.). Influence of different temperatures on Seed quality parameters of papaya (Carica papaya L.) Interaction of temperature and substrata on seed quality parameters of papaya (Carica papaya L.) Interaction of temperature and substrata on seedling dry weight (mg), seedling vigour index-i and Seedling vigour index-ii in papaya (Carica papaya L.) Seed quality as influenced by the interaction of GA3 (T) Duration (D) in papaya (Carica papaya L.) Seed quality as influenced by the interaction of GA3 (T) Duration (D) in papaya (Carica papaya L.) Influence of GA3 on Seedling vigour index-i, seedling vigour Index-II and field emergence (%) of papaya seed (Carica papaya L.) Interaction effect of KNO3 and duration on seed quality parameters of papaya seed (Carica papaya L.) Page No

11 Table No. 10(b) Title Interaction effect of KNO3 and duration on seed quality parameters of papaya seed (Carica papaya L.) Influence of KNO3 on Seedling vigour index-i, Seedling vigour index-ii and field emergence (%) of papaya seed (Carica papaya L.) Influence of Azotobacter chrococcum on seed quality parameters of papaya (Carica papaya L.) Influence of hot water soaking at 50 C for different durations on seed quality parameters of papaya (Carica papaya L.) Influence of stage of fruit maturity on fresh fruit weight(g), fresh seed weight(g) with sarcotesta, fresh seed weight (g) without sarcotesta, and seed recovery (%) of ring spot infected fruit of papaya (Carica papaya L.) Influence of ring spot infection at fruit maturity stages on seed quality parameters of papaya (Carica papaya L.) Influence of ring spot infected fruit maturity stage on seedling vigour index-i, seedling vigour index II, EC (µscm -1 ), TDH(A480) and field emergence in papaya (Carica papaya L.) Page No

12 LIST OF FIGURES Figure No Title Influence of stage of fruit maturity on fresh fruit weight (g) and fresh seed weight with sarcotesta (g) in papaya (Carica papaya L.) Influence of stage of fruit maturity on seed index (g) and seed moisture (%) in papaya (Carica papaya L.) Influence of stage of fruit maturity on germination (%) and field emergence (%) in papaya ( Carica papaya L.) Influence of stage of fruit maturity on seedling vigour index-i and seedling vigour index-ii in papaya (Carica papaya L.) Influence of stage of fruit maturity on electrical conductivity (µscm -1 ) in papaya (Carica papaya L.) Influence of different temperatures on germination (%) and speed of germination of papaya ( Carica papaya L.) Interaction of temperature and substrata on germination (%) and speed of germination of Papaya (Carica papaya L.) Seedling vigour index-i and seedling vigour index-ii as influenced by substrata and temperature in papaya (Carica papaya L.) Germination (%), seedling length (cm) and seedling dry weight (mg) influenced by the interaction of GA3 (T ) Duration (D) in papaya (Carica papaya L.) SVI, SVII and field emergence (%) influence d by the interaction of GA3 (T) Duration (D) in papaya (Carica papaya L.) Between Pages

13 Figure No Title Interaction effect of KNO3 and duration on seed germination, seedling length (cm) and seedling dry weight (mg) of papaya seed (Carica papaya L.) Interaction effect of KNO3 and duration on SVI, SVII and field emergence (%) of papaya seed ( Carica papaya L.) Influence of Azotobacter chrococcum on seed quality parameters of papaya (Carica papaya L.) Influence of hot water soaking at 50 c for different durations on seed quality parameters of papaya (Carica papaya L.) Influence of ring spot infection at fruit maturity stages On seed index (g) and seed moisture (%) in papaya (Carica papaya L.) Influence of ring spot infection at fruit maturity stages on seed germination (%) and field emergence (%) in papaya (Carica papaya L.) Influence of ring spot infection at fruit maturity stages on seedling vigour index-i and seedling vigour index-ii Influence of ring spot infection at fruit maturity stages on electrical conductivity (µscm -1 ) Between Pages

14 LIST OF PLATES Plate No. Title Between Pages 1 Different fruit maturity stages (a) (b) (c) 5(a) (b) 6(a) (b) 7 8 Influence of stage of fruit maturity on seed germination Influence of different temperature on seed quality parameters of papaya (Carica papaya L.) Interaction of temperature ( C, C and C) and substrata (between paper) on seed quality parameters of papaya (Carica papaya L.) Interaction of temperature ( C, C and C) and substrata (sand and coirpith) on seed quality parameters of papaya (Carica papaya L.) Interaction of temperature ( C, C and C) and substrata (top of paper) on seed quality parameters of papaya (Carica papaya L.) Seed quality as influenced by Interaction of GA3 and duration in papaya (Carica papaya L.) Seed quality as influenced by Interaction of GA3 and duration in papaya (Carica papaya L.) Seed quality as influenced by Interaction of KNO3 and duration in papaya (Carica papaya L.) Seed quality as influenced by Interaction of KNO3 and duration in papaya (Carica papaya L.) Influence of Azotobacter chrococcum for different durations on seed quality parameters of papaya (Carica papaya L.) Influence of hot water soaking at 50 C for different durations on seed quality parameters of papaya (Carica papaya L.)

15 Plate No Title Seed quality as Influenced by control( seed soaking at different duration) Different fruit maturity stages with ring spot infection Influence of ring spot infected fruit maturity stage on seed quality parameters of papaya (Carica papaya L) Between Pages

16 Introduction

17 I. INTRODUCTION Among the fruits which have attained a great deal of popularity in recent years, papaya ( Carica papaya L.) stands foremost, because of its easy cultivation, quick returns, adaptability to diverse soil and climatic conditions, and above all, it is an attractive delicious and wholesome fruit that is credited with multifarious uses. Papaya ( Carica papaya L.), originated from Central America and successfully introduced to all the tropical areas of the world, is now being cultivated as a commercial fruit in almost all the tropical countries of the world. It is popularly known as paw paw or papaw (British), mamao (Brazil), and lechosa (Venezuela). It was introduced in India by Dutch traders during the 16th century. Papaya is now grown widely in India, Sri Lanka, Australia, Philippines and South Africa In India, it is grown luxuriantly in the southern peninsular region of Tamil Nadu, Karnataka, Kerala and Andhra Pradesh. Papaya is also successfully cultivated in the states of Maharashtra, Gujarat, Madhya Pradesh, Uttar Pradesh, Bihar and Assam and West Bengal in subtropical region. Due to favourable climatic conditions, it performs better in South India than in North India, where low temperature and frost often limit its growth and productivity. India stands first in the area and production of papaya followed by Brazil, Nigeria, Mexico, Ethiopia, with high productivity 72.7 metric tonnes per hectare in Indonesia. The total area under this crop was 411,163 hectares and the production amounted to 10,104,917 metric tonnes with the productivity 24.6 metric tonnes per hectare. In this, india s share was hectares and the production metric tonnes with the productivity 40.9 metric tonnes per hectare (FAO, 2010)

18 The total area cultivation of papaya during increased to 102,600 hectares and the production stood at 3,911,600 metric tonnes. Among states in India, Andhra Pradesh tops the list with 19.8 M.ha followed by Gujarat15.3 M.ha., Karnataka 6.0 M.ha and West Bengal 11.1 M.ha. Fruits produced in the states are utilized as fresh fruits and only small fraction is diverted to canning and processing. In recent years, growing papaya for papain, a complex mixture of proteolytic enzymes and peroxidases production is catching momentum and there are clear indications of its bright future. Due to its striking nutritional and medicinal values, papaya fruit has occupied a unique place in the diet of people. It is a wholesome fruit having more carotene compared to other fruits such as apples, guavas, plantain, etc. It is one of the richest sources of vitamin A. It also contains vitamin C in appreciable quantity besides being high in sugars and pectins. The raw fruits are used for the treatment of gastric ulcers and other related stomach ailments. A ripen papaya fruit is delicious, nutritive, digestive and wholesome for people of all ages and hence papaya tree finds a place in almost every backyard. All these aspects have made papaya an ideal dessert fruit. Propagation by seed is the universally followed method of multiplication in papaya. Though this method does not safeguard the purity of the progeny, it is inevitable because of the absence of any commercially feasible vegetative propagation technique. With the commercialization of papaya cultivation, the demand for quality seeds of well established varieties has increased. Few attempts have been made in the past to develop effective methods of producing quality seeds and maintain their viability.

19 Taking quality into consideration, the stage of seed maturity, influence of temperature and media on seed germination and breaking dormancy, the information available on these aspects is scanty. Therefore, the present investigation entitled Seed germination studies in Papaya (Carica papaya L.) as influenced by maturity, temperature, media and dormancy breaking was undertaken at the University of Agricultural Sciences, G.K.V.K., Bangalore during with the following objectives. 1) To study the effect of fruit maturity stages on seed quality 2) To develop protocol for testing seed germination 3) To assess the presence of dormancy in fresh seeds and methods to break dormancy 4) To evaluate the quality of seeds extracted from ring spot infected fruits

20 Review of Literature

21 II. REVIEW OF LITERATURE In this chapter, the literature available is pertaining to the maturity studies, influence of temperature and media on seed germination, dormancy breaking treatments and influence of ring spot infected fruits at different maturity. Wherever information is not available on the papaya crop, other related crops are also reviewed on the relevant aspects. 2.1 Seed development and maturation Mature seeds are ovate and when taken out fresh from the fruit have a smooth surface. The sarcotesta is whitish, succulent and translucent. The cells of the outer epidermal layer of the sarcotesta, which form the seed epidermis, are smaller opposite the endotestal ridges while they are bigger in the position of furrows. The cells of the sarcotesta, on exposure to atmosphere, lose the water rapidly and ultimately disintegrate. The dried seeds, which have endotesta as the outermost covering, are black and have rough outer surface showing ridges and furrows lying parallel to their long axis. The endosperm occupies maximum space in the seed with full of food reserve. The dicotyledonous embryo is embedded in the endosperm (Singh, 1960). Jha et al., (1984) studied the biochemical changes occurring during seed germination and seedling growth of papaya. Total sugars increased and reducing sugar decreased upto 9 days in all the parts except in the seed coat. Starch content decreased throughout germination and seedling growth in all the parts. Total and water soluble proteins decreased in all parts of the seed during germination. Pandita et al., (2001) opined that chilli seeds of mature green and half-red fruits had poorer germination (at 13 C and 25 C), vigour and

22 field emergence than those taken from red-ripen fruits. Post- harvest ripening upto 10 days in half-red fruits improved seed germination, vigour and field emergence significantly Pandita et al., (2003) opined that maximum (86%) seed germination was obtained when papaya fruits were harvested at turner stage followed by ripen stage (81%) where seed extracted from over -ripe stage reduced the seed germination (53%). Turner ripen stage of fruit maturity showed higher seedling vigour than green and over-ripe. Suresh babu et al., (2003) conducted a study to ascertain the effect of three stages of fruit maturity viz., purple half yellow and full yellow and six post harvest ripening periods viz., 0, 2, 4, 6, 8 and 10 days on fruit and seed quality parameters in brinjal. Fruits harvested at complete yellow colour maturity stage and kept upto six days of post harvest ripening recorded higher fruit weight (68.11g), seed weight per fruit (1.18 g), 1000 seed weight (3.67g), germination (85.44%), field emergence (74.49%), vigour index (994),seedling dry weight (6.297 mg) and lower electrical conductivity of seed leachates (1.478 dsm-1). Krishnakumrary et al., (2004) stated that seeds extracted from fruits of 33 days after flowering recorded maximum values for fruit weight, length, and perimeter and seed number, seed weight, germination (%) and vigour index. Hence, they concluded that the optimum physiological maturity stage for oriental pickling melon (variety mudicode) for harvest for seed purpose is 33 days after flowering. Early and delayed harvests reduced quality of seeds. Jayabharathi et al., (1990) studied that brinjal fruits harvested at completely yellow stage gave the highest seed yield (102.5 kg/ha), seed recovery (34.64%), seed germination (90%) and vig our index (2201) compared to other stages.

23 Kalavathi (1990) established that the highest germination (91.2%) and vigour index (174) were observed when the seeds were harvested at 130 DAS as compared to seeds of premature stage i.e. 100 DAS (8.8% and 105, respectively) in chilli. Chaudhary et al., (1992) observed the highest germination (94.62%), seedling length (6.37 cm) a nd vigour index (11649) from the seeds harvested at full maturity and ripe with red skin. They also reported the increased seed quality parameters with increase in maturity stages in tomato. Sanchez et al., (1993) opined that bell pepper seeds extracted from mature green fruits gave higher gemination regardless of storage time. Seeds allowed to mature for short period in red fruits after harvest achieved maximum seed germination potential (88%). Naik et al., (1996) noticed that the fruits of chilli Cv. Arka Gaurav harvested at full yellow colour recorded maximum 1000 seed weight (1.69 g), germination (88%), and also the root length. Fruits harvested at full yellow colour stage compared to the fruits harvested at full green colour. Balaraj (1999) revealed tha t the chilli fruits harvested at full red colour, recorded highest germination (84.53%), seedling length (16.76cm), seedling vigour index (1418), dry weight of seedling (0.212g) and field emergence (82%), while electrical conductivity was less (1.16 ds/m) compared with other stages of harvesting. Hamsaveni (2002) observed the highest 1000 seed weight (2.20g), germination percentage (90), vigour index (822) seed dry weight (1.90mg), field emergence (81.86%) with low electrical conductivity of (1.17 ds/m) when the tomato fruits were harvested at full red colour.

24 Vinodkumar et al., (2002) noticed that chilli seeds extracted from fruits harvested at 60 DAA showed the highest 1000 seed weight (8.29g), germination (96.50%), field emergence (90.50%), shoot length ( 7.67 cm), root length (5.67 cm) and seedling vigour index (1288) compared to seeds from other stages of harvest Ganar et al., (2004) observed that the seeds extracted from the fruits harvested at 72 DAA recorded maximum germination (87.5%) with the release of dormancy after four months of storage and concluded physiological maturity was attained at 72 DAA with highest test weight in ash gourd. Dias et al., (2006) reported that the tomato seeds extracted from the fruits harvested at full red colour with a short period of post-harvest ripening recorded the highest germination (92%), seedling emergence (65%) and speed of germination (3.7) compared with the fruits harvested at green and colour break stage. Papaya fruits of the Formosa group, Tainung 01 hybrid, were harvested at maturation stage 1 (15% external color yellow) at five different times: July and November/2004 and February, May and September/2005. The fruits were stored at room temperature until they reached maturation stage 5 (more than 75% external color yellow). Seeds with and without sarcotesta were obtained at each harvest time. July/2004 showed poor germination (18 and 27%) on 15 and 30 days, although it was statistically superior when compared to seeds with sarcotesta and November/2004 resulting in (33 and 68%) on 15 and 30 days. and February/2005 the lowest germination at 15 and 30 days (23 and 67%) of seed with sarcotesta. With the removal of sarcotesta seed germination at 15 and 30 days (67 and 86%) increased significantly, indicating that the removal of sarcotesta helped to increase germination. And May was practically zero at 15 and 30 days did not differ

25 significantly from the seeds without sarcotesta showed 18% germination (at 15 and 30 days), indicating the presence of post-harvest dormancy in these seeds and September/2005 showed high germination at the 15 and 30 days (82 and 88%) likewise it was also verified for the seeds of fruit harvested in July/2004. However, the germination of seeds with sarcotesta was significantly less than that obtained for seeds whose sarcotesta was removed, which was also found in crops and November/2004 February/2005 (Tokuhisa et.al. 2007(a)). Lopes et al., (2009) observed that seeds of semi-mature fruits showed higher germination percentage than those of mature fruits, when soaked in solutions of 250 mg L -1 and 500 mg L -1 GA3. The seeds treated with 1,000 mg L -1 GA3, the highest germination percentage was observed in seeds of riped fruits. The results indicated that the immersion of seeds of semi-mature fruits in a 500 mg L -1 GA3 solution and seeds of mature fruits in a 1,000 mg L -1 GA3 solution promoted a better germination and seedlings with greater vigor. Shamsheer et al., (2009) reported that seeds obtained from fruits harvested at red ripen stage and allowed up to 14 days of post harvest ripening period recorded higher 1000 seed weight (5.78g), germination (89.10 %), shoot length (7.30 cm), root length (10.67 cm), seedling dry weight (6.820 mg) and seedling vigour index (1780) with lower electrical conductivity (1.417dSm -1 ) and seed infection (1.33 %) in chilli. 2.2 Seed size Singh and Singh (1979) reported that the thousand seed weight was important in selecting genotypes for high germination capacity. The germination percentage in large and small seed grades differed significantly only in a few genotypes. Hereditary differences exist in the

26 genotypes of papaya which can be exploited in developing quality seeded variety. 2.3 Influence of temperature and media on seed germination Seeds of different species require different temperature ranges to germinate. The most desirable temperature for germination is generally the one at which a given number of seeds achieve their maximum percent of germination over a period of time, which is considered as the optimum temperture. The maximum and minimum temperatures for germination are the highest and lowest temperatures at which germination still occurs (Copeland and McDonald, 1989). The role of media for germination is considered to be vital. Richard et al., (1964) characterized an ideal medium for germination and suggested that it should be sufficiently firm and dense, retentive of moisture, sufficiently porous, etc. Kalantyr (1968) observed that the use of vermiculate as a substrate markedly improved seed germination and seedling emergence in many medicinal plants. Germination of Polyanthus seeds covered with sand or compost improved with mist irrigation. Seed sown on wet paper germinated equally good at 15 C and 20 C. But, seeds covered with sand and tested at 20 C were found deleterious. Germination was much better at 15 C when seeds were not covered at all and although seeds did not respond to light for germination. (Turner and Heydecker, 1974) According to Mastalerz (1976) the optimum temperature for germination test of Cartharanthus roseus was C. Joshua (1978) reported that an alternating temperature of 10/25 C hastened the germination of Solanum incanum.

27 Roberts et al., (1978) opined that Solanum nigrum seeds germinated rapidly at an alternate temperature of 25/30 C. Wagenvoort and Vanopstal (1979) recommended alternate temperature for improving the germination of Solanum nigrum seeds. The optimum temperature for germination of Solanum nigrum was found 20/30 C (Kazinci and Hunyadi, 1990) Chokecherry seeds ( Prunus virginiana) gave highest germination percentage at alternate temperature at C and after stratification at 3 C for 16 weeks and it was on par with 14 weeks of stratification (Lockley, 1980) Jethani (1982) reported 15 C and between paper were best suited for testing the germination of coriander. Among three media viz., 100 per cent soil, 100 per cent sand and 50 per cent soil + 50 per cent sand, 100 per cent soil was found to be the best for Diphysa robiniodes (Mora and Rodrieviz, 1982). According to Horowitz and Givelberg (1983) Solanum nigrum seeds did not germinate in dark but in light they germinated between 20 C and 35 C temperature with optimum of 25 C. Furutani and Nagao (1989) reported that seeds germination of papaya increased when preconditioned at 24 C for 0,1,3,5,7 and 30 days before transfer to 32 C from 9%, 4%, 13%, 16%, 29% and 60%. And preconditioning for 1 or 7 days at 32 C followed by second preconditioning at 24 C for 29 or 23 days and maintained at 32 C gave 70% and 45% germination. However, preconditioning at 32 C followed by transfer to 24 C did not increase germination.

28 Tarkeshwar Singh et al., (1990) standardized the temperature and medium required for fenugreek at 20 C (constant) and between paper for maximum germination. Ferrari (1991) showed that sand m edium was found as most suitable substrate for testing germination of seeds of triticale. Kumar et al., (1991) reported that in six varieties of cotton, tested in soil (in the field), sand and paper towel showed lowest germination and lowest emergence. Zade et al., (1991) reported that 25 C temperature and between paper medium was found best for testing the germination of niger seeds. Zade et al (1992) recommended alternate temperature 20 C/30 C or constant 30 C temperature and between paper medium for testing germination of rice bean Seeds of Ephedra gerardiana gave better germination (95%) on sand media (Bhagat et al., 1992) Ganigara et al., (1995) recommended the constant temperature of either 25 C or 30 C with sand medium to test the seeds of Tamarindus indica. In Acacia nilotica, constant temperature of 30 C, between paper as substratum and first count on day 3 and final count on day 7 were found to be optimum. Kurdikeri et al., ( 1995) reported that between the two media (between paper and sand), the germination and speed of germination of maize were found in sand than between paper medium. Sivasubramanian (1996) found that C temperature and sand medium as best for testing the germination of moringa seeds.

29 In Pithecolobium dulse, the alternate temperature of C in TP or BP and in Switenia mahogany, maximum germination per cent was observed at C in between paper method (Nazir Miyan, 1997). Anonymous (1998) standardized the temperature and medium for true potato seed as 20 C or C and top of paper. The first and last counts can be taken on 8 th and 18 th day respectively and also revealed that 30 C constant temperature and sand medium were best for testing the pasture grasses. Gangare et al., (1998) recommended top of paper method for Andrographis paniculata and Helicteres isova and between paper method for Thespesia populanea for better and quick germination. According to Suryawanshi et al., (1998) top of paper media was found to be best for conducting germination test in Solanum viarum, Artemisia pallens and Cassia angustifolia. Yogeesha et al., (2007) stated that alternate temperature of 20 C for 16 hr and 32 C for 8 hr was found optimum for papaya seed germination with 69.5, 92.0 and 61.5 percent in fresh seeds of Surya, CO2 and CO7 as against 0.0, 11.5 and 2.0 percent respectively and seeds without any treatment at constant temperature of 25 C. 200 ppm was found effective at 25 C in all cultivars with 85.0, 69.3 and 75.0 percent germination in Surya, CO2 and CO7 respectively. Okeyo and Ouma (2008) reported that per cent germination of papaya seed was similar to washed and unwashed top soil but for sand it was 70% germination for washed and 40% germination for unwashed. Washing seeds before sowing improved germination in sand but not in top soil. The presence of the gelatinous material (sarcotesta) reduced the

30 average percent germination. Washing the seeds resulted in increased germination. 2.4 Breaking of Seed dormancy The germination capacity of papaya seeds is generally low due to the presence of dormancy. Any chemical treatment given may release the seed dormancy.seed germination response of certain cultivated papaya plants to various physical and chemical treatments aimed at breaking dormancy and thereby improving germination percentage are given below. Seed dormancy and germination are complex adaptive traits of higher plants that are influenced by a large number of genes and environmental factors. Studies of genetics and physiology have shown the important roles of the plant hormones abscisic acid and gibberellin in regulation of dormancy and germination. (Koornneef et al., 2002). Koyamu (1951) reported that treating the papaya seeds with ash and soaking in cow s urine before sowing, increased the germination percentage & also induces early germination and vigorous seedlings. Chacko et al., (1966) reported that pre-sowing treatment of papaya seeds with GA3 at concentration of 50, 100, 250, 500 and 1000 ppm resulted in an increased rate of germination, but did not affect the germination percentage. Sen and Ghunti (1976) reported highest germination percentage of papaya seeds cv. Ranchi in non- chilled seeds with GA 200 ppm followed by GA 100 ppm. Chilling alone had no beneficial effect on seed germination.

31 Enhancement in germination, plant height, plant dry weight and yield was noticed when okra seed was treated with GA3 and IAA (Omran et al.,, 1980). Peres et al., (1980) revealed that immersion of papaya seeds in a nutrient solution containing KNO3 and KH2PO4 reduced significantly the germination in the three year old seeds and increased germination in the zero (0) year old seeds of P.R Reyes et al., (1980) stated that the natural growth inhibitors of papaya seeds might be minimized by removing sarcotesta (the gelatinous envelope) of the seed, which contains the most endogenous growth inhibitors, plus a careful washing to eliminate the soluble inhibitors of the sclerotesta during the extraction of seeds from fruits. Hari Singh et al., (1985) revealed that the germination of muskmelon seeds, improved when separated and washed after 24 hour of fermentation. Per cent germination was highest when the fruits were harvested at full maturity stage. Poor germination in Carica papaya L. was partly due to the absence of embryos in about 20% of the seeds. Final germination and the rate of seedling emergence were improved by seed separation with sucrose solution soaking with 1.0M potassium nitrate or 600 ppm gibberellic acid. Final germination was 87.8% for the potassium nitrate treatment and 80.5% for gibberellic acid. Seedlings from potassium nitrate treatments were normal whereas gibberellic acid caused excessive elongation of stems (Nagao and Furutani, 1986). Pepper seeds treated with KNO3 solution were found to increase mean rate of germination with advancement of hypocotyl development, but seed germination per cent was not affected (Sundstorm and

32 Edwards, 1989). In tomato seeds treated with KNO3 and KH2PO4, improved germination and reduction in time taken for 50 per cent germination have been noticed (Alvarado et al., 1987). Begum et al., (1987) observed that 0.2 percent thiourea, 50 and 100 percent cattle urine were highly detrimental to the papaya seed germination and seedling growth. Treatments with 50 and 100 ppm GA, accelerated the growth of seedling (length and fresh weight) Furutani and Nagao (1987) noticed that papaya seeds soaked in potassium nitrate (KNO 3) or gibberellic acid (GA 3) for 15 minutes exhibited an increased percentage emergence and reduced time for 50% seedling emergence in compared to seeds soaked in water. Increasing the KNO3 concentration from 0 to 1.0 M and GA3 from 0 to 1.8 Mm increased percentage seedling emergence 9.8 and 5.5 fold over the controls at 25 C; and at 35 C emergence was increased 4.0 and 3.1 fold respectively. Begum et al., (1988) reported that papaya seeds stored for one, two, and three months recorded decreased germination of 75, 49 and 6.3 percent respectively. Pre- soaking of seeds in GA3 (50-200mgl -1 ) did not increase the germination percentage but enhanced the vigour. Thiourea treatment (4-10gl -1 ) on the other hand had an inhibitory effect on both the germination percentage and vigour. Ariyaratne et al., (1993) observed that the cucumber seeds which have cut through the radical end damaged the nucellar membrane and when seeds were soaked in 0.34 M NaCl for 16 h and kept for germination, the treatment has overcome dormancy in 94 percent of the seeds compared to zero (0%) in the uncut control. Claudinei et al., (1993) observed that combining matriconditioning with 100 or 200 µm GA4+7 could effectively reduce germination time and

33 improve seedling emergence and recommended as a standard procedure for testing papaya seed germination. There were significant differences in germination and seedling vigour index of seeds treated with 200 mm, 150 mm and 150 mm over the untreated control in tomato, capsicum and onion. (Jagadish et al., 1994). Renugadevi et al., (1994) reported that soaking of bittergourd seeds with KNO3 (1%) has given maximum germination percentage (100), vigour index (1540) and speed of germination (25.82) compared to control (54, 1209, 9.89 respectively). Patil et al., (1995) stated that pre sowing treatment urea plus micronutrient solution was found the best for seed germination of papaya followed by ascorbic acid solution as compared to control. Sathiyamoorthy and Nakamura (1995) studied the effect of GA and inorganic salts in breaking dormancy and enhancing germination of true potato seeds. Both GA3 and GA4 eliminated seed dormancy and GA3 (1000 ppm) enhanced germination. Seeds soaked for 4 days in one per cent KNO3 eliminated dormancy and reduced mean germination time. Christopher et al., (2000) noticed that dormancy could be removed in a large proportion of the population by the application of a single heat shock to rehydrated seeds for 4 hr, with at 36 C, with subsequent return to 26 C for germination and also reported that dormancy was re-imposed in heat shocked seeds when they were subsequently dried to seed relative humidities of 25 to 75 per cent (5 to 11% moisture content (fresh weight basis) in papaya.

34 Germination per cent and seedling vigour index in tomato cv. Pusa ruby were found influenced by inorganic salts such as 1%, 1%, (Gayathri, 2001). Nalini et al., (2001) reported that soaking of onion seeds in GA3 (100 ppm) has given highest germination (88.70%) compared to control (82.0%). Yogananda et al., (2004) noticed that bell pepper seeds invigorated with GA3 (200ppm) or KNO 3 (1.0%) recorded higher germination, root and shoot length, seedling dry weight, rate of germination and seedling vigour index over control. Tokuhisa et.al., (2007)(b) noticed that seeds with sarcotesta had lower germination speed and percentage. The best treatments to overcome dormancy in papaya seeds were the use of substratum moistened with GA3 600 ppm or the immersion of the seeds GA3 600 ppm for 24 hours and immersion of the seeds in KNO3 1M for 30, 60 and 90 minutes. Lopes et al (2009) reported that papaya ( Carica papaya L.) hybrid group 'Tainung 01' seeds from semi-mature fruits showed higher germination percentage than those from mature fruits, when soaked in solutions of 250 mg L -1 and 500 mg L -1 GA3. For ripe fruit seeds treated with 1,000 mg L -1 GA3, the highest germination percentage was observed. The results showed that immersion of seeds of semi-mature fruits in a 500 mg L -1 GA3 solution and seeds of mature fruits in a 1,000 mg L -1 GA3 solution have promoted a better germination and vigour. Anburani and Shakila (2010) reported that highest germination percentage (78.3%) were noticed in the seeds treated with GA ppm for 12 h followed by the seeds treated with thiourea 2000 ppm for 12 h

35 (75.3). The least germination percentage (38.1) recorded in the control. The time taken for 50% germination was also earlier (20 days) in seeds soaked in GA3 200 ppm for 12h which was also on par with seed treatment with thiourea 2000 ppm for 6 h (20 days). Longer duration for 50% germination was recorded in the control (29 d ays).the maximum shoot and root length of 14.9 and 8.4 cm respectively observed in seeds treated with GA3 200 ppm for 12 h followed by seed treatment with thiourea 2000 ppm for 12 h (13.9 and 8.2 cm respectively). The shoot and root length was minimum (5. 4 and 4.1 cm respectively) in the control. The vigour index was maximum (1826) in the seeds treated with GA3 200 ppm for 12 h followed by seeds treated with thiourea 2000 ppm for 12 h (1668). Barche et al.,(2010) found that the maximum germination (78.50%) was recorded in Hybrid Mayuri soaked in gibberellic acid at 500 ppm, while minimum (42.62%) was observed in Pusa Nanha soaked in urea at 2%.Early germination (15 days) was noticed in Hybrid Mayuri followed by Pusa Nanha (15.75 days) soaked in gibberell ic acid at 500 ppm. Maximum days taken for completion of germination (23 days) in Pusa Nanha, soaked in boron at 2 ppm Maximum seedling height (12.79 cm) was observed in Hybrid Mayuri soaked in gibberellic acid at 500 ppm. Deb et al.,(2010) recorded that maximum germination (72.20%) in papaya seed treated with GA3 at 100 ppm followed by sodium thiosulphate 20 ppm (67.76%) and seedling height was maximum (52.32cm) in GA3 200ppm at 90 days after sowing followed by borax at 0.50% +znso4 at 0.25% (48.34 cm) and sodium thiosulphate at 20ppm (47.56cm). Dhinesh babu et al., (2010) observed as the increasing the concentration GA3 from 0 to 100 ppm, there was significant improvement in the germination (66.17%) over the control (42.40%). At the o ptimal

36 concentration of GA3 at 100 ppm, the maximum germination was manifested by Coorg Honey Dew (84.00%) followed by Pant Papaya (80.20%).The performance of Coorg Honey Dew was superior by 67.33% and 26.88% over that of Washington which expressed the minimum germination and mean germination respectively. Seeds treated with GA3 showed a significant effect in enhancing the seedling length. The mean seedling length at 60 days was maximum with GA3 100 ppm (17.39 cm) against control (10.98 cm).and the maxim um vigour index ( ) in GA3 treated at 100 ppm in Coorg Honey Dew closely followed by Pant Papaya ( ) and lowest in Washington (702.60). Feza Ahmad (2010) reported that maximum seed germination (67.25 and 53.00%) with the application of 2000 ppm GA3 in cvs. Bruno and Hayward respectively. Whereas, the minimum seed germination (48.62 and 45.87%) was registered with 500 ppm GA3 in cvs. Bruno and Hayward respectively. There were no significant difference on seed germination of Hayward variety when seeds were treated either with 1,500 or 2,000 ppm GA3 indicating that 1,500 ppm is optimum for economic and better seed germination for cv. Hayward. 2.5 Effect of Azotobacter chrococcum Azotobacter is a heterotrophic free living nitrogen fixing bacterium that grows successfully in the rhizospheric zone of sunflower, cotton, potato and many others and fix kg N ha -1 per cropping season (Sudhir and Shende, 1982; Jadhav et al.,, 1987). The bacteria produce abundant slime which helps in soil aggregation. It serves as a broad spectrum inoculant and is found to increase the per cent seed germination and root proliferation.

37 Bhanavese et al., (1990) recorded the highest root and shoot length of garlic due to the treatment of Azotobacter under pot culture conditions. Govedarica et al., (1993) reported that the production of growth substances by nine Azotobacter chroococcum strains isolated from a chernozem soil showed that these strains have the ability to produce auxins, gibberelins, and phenols and in association with the tomato plant, it increased plant length, biomass, and nitrogen content. Pamar and Dadarwal (1997) reported that the beneficial effect o f Azotobacter is attributed to production of plant growth hormones, improved nutrient uptake and antagonistic effect on plant pathogens. Kader et al., (2002) while studying the effect of Azotobacter inoculant on the yield and nitrogen uptake by wheat found that the free living nitrogen fixer Azotobacter in the rhizospheric zone have the ability to synthesize and secrete some biologically active substances like B vitamins, nicotinic acid, pantothenic acid, biotin, heteroauxins, gibberellins, etc. which enhances the root growth. Pathak et al., (2002) tested Azotobacter chroococcum HT54, a high temperature resistant mutant as an inoculant on four cultivars of Indian mustard, Brassica juncea viz. Kranti, RH 30, RN 393, and Varuna under semi- arid conditions. All the four varieties gave better yield response with HT 54 inoculation and RH 30 was found to be the best, followed by Kranti and RN 393. Soleimanzadeh et al., (2008) studied the effect of seed inoculation by Azotobacter and different levels of nitrogen fertilizer on the growth and yield of sunflower. Azotobacter inoculation showed improved plant height, biological yield and oil content which were significantly higher

38 than uninoculated plants. Application of Azotobacter in presence of 50% recommended N had increased the seed yield and oil production to an acceptable level. Mirzakhani et al., (2009) reported that the application of Azotobacter increased the available nitrogen in the soil which could enhance the seed yield in safflower. 2.6 Papaya ring spot virus Papaya Ring Spot Virus (PRSV) has been reported from every continent, wherever papaya is grown. Of the total 12 viruses reported on papaya, PRSV is the most destructive and has been the major constraint and limiting factor for its cultivation in all tropical and subtropical regions. In India, the first report of PRSV was made by Capoor and Verma (1948) as papaya mosaic, subsequently it was reported in Bihar by Mishra and Jha (1955) as mosaic, from Madhya Pradesh by Garga (1963), from Uttar Pradesh by Khurana and Bhargava (1970). Later Surekha et al., (1977) recorded incidence of PRSV in Udaipur of Rajasthan. From Marathwada region of Maharastra, Yemewar and Mali (1980) severe incidences of PRSV were reported from Punjab by Cheema and Reddy (1985), papaya mosaic virus, from Andhra Pradesh by Susan John (1985), as papaya mosaic. Ramakrishna Rao (1988) from Maharashtra stated that the virus causing mosaic, leaf distortion, shoe stringing and rings on fruits of papaya was PRSV P, a member of potyvirus group. In Karnataka, Byagdi et al, (1995) recorded a severe incidence of PRSV from northern parts of the state; later Shaikh (1996) recorded the incidence of PRSV from Dharwad and Belgum districts of Karnataka, respectively. Singh et al., (2003) recorded a virus on papaya in Eastern

39 Uttar Pradesh causing severe mosaic and distortion of leaves followed by ringspots on fruits and confirmed the virus serologically as PRSV. Shaikh (1996) reported that Myzus persicae was the most efficient and principal vector for PRSV showing 80 per cent transmission followed by Aphis gossypii, A. craccivora and Pentalonia nigronervosa. Appearance of symptoms was early in case of plants inoculated with Myzus persicae as compared to other vectors. Apparently seed transmission of viruses is noticed, but in many of the cases it fails. Various workers have reported that PRSV is not seed transmitted through papaya seeds (Wang, 1982, Prasad and Sarkar, 1989). Whereas a rare incidence of two out of 1355 seedlings, showing symptoms closely related to PRSV was noticed by Bayot et al., (1990). In contrast to this, again earlier reports were confirmed by Shaikh (1996) in his experiment involving one thousand seedlings raised out of PRSV infected papaya fruit seeds even after 12 months and again similar observations were recorded by Lakshminarayan Reddy (2000). Lakshminarayan Reddy (2000) reported that Myzus persicae, showed 90 per cent, Aphis gossypii 70 per cent and Aphis craccivora 50 per cent transmission of PRSV from papaya to papaya. Maximum transmission of 90 per cent was recorded with 12 aphids per plant and minimum of 10 per cent with one aphid.

40 Material and Methods

41 III MATERIAL AND METHODS The investigation on the effect of fruit maturity stages on seed quality, ideal temperature and media, methods of breaking dormancy and effect of ring spot infected fruits on seed quality of papaya (Carica papaya L.) surya was assessed in the laboratory at the Department of Seed Science and Technology,UAS, G.K.V.K., Bangalore. The materials used and the techniques adopted during the course of investigation for collection of data, analysis and interpretation of data are described in this chapter. 3.1 General Description Papaya fruits were harvested from field of Krishi Vigyan Kendra, (IIHR) Hirehalli, Tumkur. It lies between 13 N latitude and 77 E longitude at 845 m above MSL. 3.2 Effect of stages of harvest of fruit on the seed quality of papaya (Carica papaya L.) The fruits were harvested at different maturity stages from papaya field of K.V.K. (IIHR) Hirehalli, Tumkur and subjected to following treatments. Treatment: T1: 1/4 th yellow/orange stage before ripening T2: 1/2 yellow/orange stage before ripening T3: 3/4 th yellow/orange stage before ripening T4: Complete yellow/orange stage before ripening T5: 1/4 th yellow/orange stage till ripening upto 7 days T6: 1/2 yellow/orange stage till ripening upto 5 days

42 T7: 3/4 th yellow/orange stage till ripening upto 3 days T8: Complete yellow/orange stage till softening upto 2 days Twenty fruits of uniform shape and size were manually harvested carefully without any mechanical damages from each maturity stages as listed above. In each maturity stage, ten out of 20 fruits were subjected to seed extraction soon after harvest and remaining ten fruits are subjected to seed extraction after complete ripening. Treatment: T1: 1/4 th yellow/orange stage of freshly harvested fruits T2: 1/2 yellow/orange stage of freshly harvested fruits T3: 3/4 th yellow/orange stage of freshly harvested fruits T4: Complete yellow/orange stage of freshly harvested fruits T5: 1/4 th yellow/orange stage ripened for 7 days T6: 1/2 yellow/orange stage ripened for 5 days T7: 3/4 th yellow/orange stage ripened for 3 days T8: Complete yellow/orange stage ripened for 2 days Design: Complete randomized design Replications: Four Seed extraction The fruits of appropriate maturity stage were cut into two halves longitudinally. Seeds were scooped out of the fruit using a stainless steel spoon with a soft edge. Such seeds which contained the sarcotesta (outer slimy covering of the seed) were removed of the sarcotesta by scrubbing the seeds using cotton cloth and washed with running water repeatedly to remove slimy sarcotesta. Such cleaned seeds were once again

43 Freshly harvested fruit 1/4 th yellow/orange 1/2yellow/orange 3/4 th yellow/orange Completeyellow/orange Post harvest ripened 1/4 th yellow/orange stage 1/2 yellow/orange stage 3/4 th yellow/orange stage Complete yellow/orange stage Plate 1. Different fruit maturity stages

44 subjected to manual cleaning to eliminate any traces of unwanted materials such as inert matter, etc. The wet seeds were placed in plastic trays. The seeds were uniformly spread to a thin layer and allowed to dry under shade until safe storage moisture content (8%) was attained Germination test The germination test was conducted for seeds by employing Between Paper method as prescribed by ISTA (1996). The germination counts were taken every day until the completion of germination. The cumulative germination was calculated on the basis of number of seedlings germinated on each day. Besides, the fresh ungerminated, abnormal and chaffy seeds were also identified as per ISTA (1996) and expressed in percentage to reveal the occurance of dormancy The following observations were recorded: Fresh fruit weight (g) The weight (g) of individual fruit just before seed extraction was recorded using a physical balance Fresh seed weight (g) The weight of seeds (g) with existing moisture content, after cleaning was recorded using a precision weighing balance Dry seed weight (g) The weight of seed (g) after drying the seeds to safe storage moisture content (8% MC) was recorded Seed moisture content after harvest (%) The seeds were extracted from the fruit of each maturity stage and five grams of seeds were drawn from extracted seeds of each treatment in

45 four replications and were pre dried in an oven at 70 C for 4 hours, depending on the initial water content. Thereafter, the trays are left open in the laboratory for two hours. Then weight was recorded and again subjected to oven dried at 102±1 C for 17 hour. After cooling in desiccator their final weight was recorded and moisture content of the seeds was determined on wet basis by using the following formula. Moisture Content (%) = S1 + S2 S1 X S2 100 Where, S1 = percentage of moisture lost by pre-drying (stage 1) S2 = percentage of moisture lost by the oven method (stage 2) Seed recovery (%) The seed recovery (%) was calculated based on the quantity of seeds obtained with fruit of net plot area. Seeds were dried to seven to eight per cent moisture content and seed recovery was calculated by using the formula as stated below Seed recovery (%) = W2 W1 X 100 Where, W1 fruit yield of net plot (g) W2- weight of seeds yield obtained from net plot area after drying (g) Seed index (g) Test weight was determined by counting 1000 seeds of four replicatios from each of the different matured fruits at random, and weighed and expressed in grams as the weight of 1000 seeds.

46 Electrical conductivity (µscm -1 ) The electrical conductivity of seed leachate was determined as per the procedure outlined by ISTA (1995). Three replication of 25 seeds each was taken randomly and soaked in 25ml of distilled water for 18 hours at constant temperature at 25 C ± 1 C after incubation, the seed leachate was decanted and the conductivity was measured by digital conductivity meter (model-di 9009) and expressed in µscm Total dehydrogenase activity (A480) Tz vigor test of different vigour levels was determined by estimating the total dehydrogenase activity as per the method described by Perl et al. (1978). Ten seeds are selected randomly and preconditioned by imbibing the seeds for 24hours.After the removal of seed coat, the embryos were soaked in 0.5 per cent 2,3,5-triphenyl tetrazolium chloride (TTC) solution in a test tube and incubated at 25 C ± 1 C in dark for 16 hours. Then they were washed thoroughly with distilled water, the red coloured formazan from stained embryos was extracted, by soaking the stained embryos with 5ml of 2- methoxy ethanol for 8 hours in an airtight container. The extract was decanted and the colour intensity was measured with the help of spectrophotometer (Model-Systronics UV-VIS spectrophotometer 1l7) at 480 nm. The dehydrogenase activity was expressed in terms of Absorbance at 480 nm Fixing the first count and final count The first and final count of germination were fixed based on the daily germination count as per the specifications of ISTA (Anon., 1985)

47 Germination (%) The laboratory germination was recorded at two stages giving the first count at the end of 15 days and the second count at the 20 days as per the standardization Seedling length (cm) Ten seedlings from germination test in each replications were randomly selected for the measurement of root and shoot lengths in centimeters on the day of final count. The shoot length was measured from collar region to the point of attachment of cotyledon and root length from the collar region to the tip of the primary root Seedling dry weight (mg) Ten seedlings selected for seedling length measurement were utilized to determine dry weight of seedling. These seedlings were dried in hot air oven at 80 C for 24 h and dry weight per seedling was expressed in milligrams (mg) Seedling vigour index Seedling vigour index (SVI) and (SVII) of seedling was calculated by adopting the method suggested by Abdul-Baki and Anderson (1973) and expressed as whole number. The formula used to estimate the SVI and SVII is as follows: Seedling vigour index (SVI) = Germination (%) Mean seedling length (cm) Seedling vigour index (SVII) = Germination (%) Mean seedling dry weight (mg)

48 Field emergence Field emergence was recorded similar to that of laboratory germination, but only those emerged out and established into normal seedlings were recorded on 15 th and 20 th day 3.3 Effect of different temperature and media on seed germination of papaya (Carica papaya L.). The seeds extracted from matured papaya fruits are subjected to germination at different temperature and evaluated for ideal temperature. From the experiment the standard temperature range at which germination percentage was higher, was taken as ideal temperature for further studies Influence of temperatures on seed germination The fresh seed is extracted from matured papaya fruits which had high initial moisture content were dried to safe moisture content of 8% by spreading on open air trays. The germination test was carried out in double chamber seed germinator. For alternate temperature, the lower temperature was maintained for 16 hours and higher temperature for 8 hours on each day. The germination paper was used for the test as per ISTA specification (Anon., 1985). The paper being used in the study was porous and free from toxic chemicals and water soluble dyes. For seed germination, the rolled towel method was used. The rolled towels were placed in slant position in the germinator maintained in the required temperature levels as per the treatment schedule 3.2.1

49 Treatments T1: 20 C T2: 25 C T3: 30 C T4: 35 C T5: C T6: C T7: C Design: Complete Randomized Design Repilication: four Record of observations Germination (%) The germination was recorded at two stages giving the first count at the end of 15 days and the second count at the 20 days as per the standardization Speed of germination Speed of germination was determined by putting 50 seeds in rolled towels and germinated at alternate temperature (20-30 C). Daily counts of germinated seeds (seedlings having minimum four centimetre root and two centimetre shoot were considered as normal seedlings) were recorded upto final count. An index of speed of germination was calculated. It is the summation of the number of seeds germinated on specific day divided by reciprocal of a day on which seedlings were counted and removed (Maguire, 1962 and Dadlani, 1982). Speed of germination = + +

50 Where N1, N2, , Nn = No. of emerged seedlings 1, 2 and n days after planted D1, D2, , Dn = No. of days after planted Seedling length (cm) Ten seedlings from germination test in each replications were randomly selected for the measurement of root and shoot lengths in centimeters on the day of final count. The shoot length was measured from collar region to the point of attachment of cotyledon and root length from the collar region to the tip of primary root Seedling dry weight (mg) The ten seedlings selected for seedling length measurement were utilized to determine dry weight of seedling. These seedlings were dried in an hot air oven at 80 C for 24 h and dry weight per seedling was expressed in milligrams (mg) Seedling vigour index Seedling Vigour index (SVI) and (SVII) of seedling was calculated by adopting the method suggested by Abdul-Baki and Anderson (1973) and expressed as whole number. The formula used to estimate the SVI and SVII is as follows: Seedling vigour index (SVI) = Germination (%) Mean seedling length (cm) Seedling vigour index (SVII) = Germination (%) Mean seedling dry weight (mg)

51 3.3.2 Effect of different media on seed germination of papaya (Carica papaya L.) The seeds were extracted from matured papaya fruits were subjected to different media for germination in ideal temperature (20-30 C, C & C) selected from experiment II and evaluated for ideal media. MEDIA T1: Between paper T2: Top of paper T3: Sand T4: Coir pith Design: Complete Randomized Design Replication: four The fresh seeds extracted from matured papaya fruits which had high initial moisture content were dried to safe moisture content of 8% by spreading on open air trays. The seeds were put to germination in Between the paper, Top of paper by using blotters and pots containing sand and coir pith The germination test was carried out in double chamber seed germinator. For alternate temperature the lower temperature was maintained for 16 hours and the higher temperature for 8 hours on each day. The germination paper was used for the test as per ISTA specification (Anon., 1985). The paper being used in the study was porous and free from toxic chemicals and water - soluble dyes. Paper as substratum was used in two methods viz., Between paper method (BP) and Top of paper (TP)

52 Between paper method Hundred seeds of four replicates were placed between two layers of moist Kraft paper and then rolled. The rolled towels were placed in slant position in the germinator maintained at required temperature levels as per the treatment schedule Top of paper Two moist Whatmann filter paper (No.1) were placed in the glass petridish of 20 cm diameter. Fifty seeds of four replicates were sown and incubated at the required temperature. The lid was covered to minimize the evaporation loss. The petriplates were placed in the seed germinator maintained at the required temperature levels as per the treatment schedule Sand medium The sand was sieved through 0.05 mm diameter mesh and repeatedly washed in running water and sterilized in a hot air oven as specified by ISTA (1996). The sand was filled in plastic pots measuring 12.5 cm diameter. The sand was moistened with sterilized water. 25 seeds of eight replicates were placed at equidistance on moist sand and covered with another thin layer of sand. After planting the seeds, the sand pots were kept inside the seed germinator maintained at different temperatures as per the treatment schedule Coir pith medium The coir pith was cleaned and repeatedly washed in running water and sterilized in a hot air oven as specified by ISTA (1996). The coir pith was filled in plastic pots measuring 12.5 cm diameter. The coir pith was moistened with sterilized water. 25 seeds of eight replicates were placed

53 at equidistance on a layer of moist coirpith and covered with thin layer of coir pith. After placing the seeds in different media were kept inside the germinator and maintained different temperatures as per treatment details. The substratum under each treatment was kept with sufficient moisture to meet the requirements for germination Record of observations Germination percentage The germination was recorded in two stages giving the first count at the end of 15 days and the second count at the 20 days as per the standardization Speed of germination Speed of germination was determined by putting fifty seeds in rolled towels kept in slant position in seed germinator. Daily counts of germinated seeds (normal seedlings) were recorded upto final count. An index of speed of germination was calculated, it is the summation of the number of seeds germinated on specific day divided by reciprocal of a day on which seedlings were counted and removed (Maguire, 1962 and Dadlani, 1982). Speed of germination = + + Where N1, N2, Nn = No. of emerged seedlings 1, 2 and n days after planted D1, D2, Dn = No. of days after planted

54 Seedling length (cm) Ten seedlings from germination test in each replications were randomly selected for the measurement of root and shoot lengths in centimeters on the day of final count. The shoot length was measured from collar region to the point of attachment of cotyledon and root length from the collar region to the tip of primary root Seedling dry weight (mg) The ten seedlings selected for seedling length measurement was utilized to determine dry weight of seedling. These seedlings were dried in a hot air oven at 80 C for 24 h and dry weight per seedling was expressed in milligrams (mg) Seedling vigour index Seedling Vigour Index (SVI) and (SVII) of seedling was calculated by adopting the method suggested by Abdul-Baki and Anderson (1973) and expressed as whole number. The formula used to estimate the SVI and SVII is as follows: Seedling vigour index (SVI) = Germination (%) Mean seedling length (cm) Seedling vigour index SVII = Germination (%) Mean seedling dry weight (mg) 3.4 Studies on seed dormancy breaking methods in papaya This experiment was conducted in the laboratory conditions of the department of seed science and technology, for this experiment the papaya fruits of complete yellow/orange stage were selected and harvested and the seeds from these fruits were extracted by adopting the earlier mentioned seed extraction method listed in 3.1.1

55 The extracted seeds were further dried to 8 per cent moisture content by keeping them under open air conditions and soon after seed extraction the seeds were subjected to different methods of breaking of dormancy of papaya seeds as follows Treatments of seeds: Experiment I. Effect of Giberellic acid on breaking of seed dormancy of papaya. This experiment was conducted as follows I factor: Giberellic acid concentration (T) T1: 100ppm T2: 200ppm T3: 300ppm T4: 400ppm T5: Control (water soaking) II factor: Soaking duration (D) D1: 12 hours soaking D2: 24 hours soaking D3: 36 hours soaking D4: 48 hours soaking

56 Experiment II. Effect of Potassium nitrate on breaking of seed dormancy of papaya. This experiment was conducted as follows I factor: Potassium nitrate concentration (T) T1: 0.5% T2: 1 % T3: 1.5% T4: 2% T5: Control (water soaking) II factor: Soaking duration (D) D1: 12 hours soaking D2: 24 hours soaking D3: 36 hours soaking D4: 48 hours soaking Experiment III. Effect of hot water soaking on breaking of seed dormancy of papaya. This experiment was conducted as follows I: Hot water 50 C (T) T1: 10minutes T2: 20minutes T3: 30minutes T4: 45minutes

57 Experiment IV. Effect of Azotobacter chrococcum on breaking of seed dormancy of papaya. This experiment was conducted as follows I: Azotobacter 5g/kg of seed (T) T1: 5days T2: 10days T3: 15days T4: 20 days Design: Complete Randomized Design Replication: four Preparation of test solutions Giberellin (GA3) The required quantity of gibberellins (GA 3) was dissolved in little absolute ethyl alcohol solution and then diluted with distilled water to give a stock solution of 1000 ppm. From the stock solution, further dilutions were made according to the treatment requirement by using distilled water Potassium nitrate (KNO3) It was prepared by dissolving 20 g of KNO3 in distilled water and volume was made upto 1000 ml. From the stock solution, further dilutions were made according to the requirement by using distilled water Giberellin treatment The seeds were soaked in Giberellic acid (GA 3) solution at four different concentrations 100 ppm, 200ppm, 300ppm, and 400ppm for

58 (12hr, 24hr, 36hr, and 48hr). About hundred seeds in four replicates, for every treatment was used and they were tested for germination Potassium nitrate (KNO3) treatment The Seeds were soaked in KNO3 solution at four different concentrations 0.5 (%), 1 (%), 1.5 (%), 2 (%) for (12hr, 24hr, 36hr, and 48hr). About hundred seed in four replicates, for every treatment was used and tested for germination Azotobacter chrococcum treatment Seeds were treated with 5g of Azotobacter chroccum per kg of seed for (5days, 10 days, 15 days and 20 days).hundred seeds in four replicates, for every treatment were used and tested for germination Hot water treatment Hundred seeds were tied in a muslin cloth bag in four replicates and exposed at 50 C for (10min, 20min, 30min, and 45min respectively) and tested for germination Control (water soaking for 12hr, 24hr, 36hr, and 48hr) As per treatment schedule hundred seeds in four replicates were immersed in water for 12hr, 24hr, 36hr, and 48hr at room temperature and tested for germination Field emergence Different treatment treated seeds in twenty five each in four replicates were sown in open field and polyhouse conditions in well prepared bed. The emergence was noted at final count of germination. After treatment, following observations were recorded

59 3.4.9 Germination (%) The seeds were tested for germination by adopting BP method as per ISTA (1996).The germinated seedlings were evaluated on the final day of germination test. The total germination was expressed as per cent on the basis of number of normal seedlings obtained Seedling length (cm) Ten normal seedlings from each replications were randomly selected for the measurement of root and shoot lengths in centimeters on the day of final count. The shoot length was measured from collar region to the point of attachment of cotyledon and root length from the collar region to the tip of primary root Seedling vigour index Seedling Vigour Index (SVI) and (SVII) was calculated by adopting the method suggested by Abdul-baki and Anderson (1973) and expressed in whole number. The formula used to estimate the SVI and SVII is as follows: Seedling Vigour Index (SVI) = germination (%) Mean seedling length (cm) Seedling Vigour Index (SVII) = germination (%) Mean seedling dry weight (mg) 3.5 Evaluation of the quality of seeds extracted from ring spot infected fruits The ring spot virus infected fruits were observed in variety red lady grows in Hosakote field. The infected fruits were collected on the basis of different maturity level and studies were carried out as follows

60 Treatments T1. 1/4 th yellow/orange stage T2. 1/2 yellow/orange stage T3. 3/4 th yellow/orange stage T4. Complete yellow/orange stage T5. Control (complete yellow/orange stage without infection) Design: Complete Randomized Design Seed extraction was done as described per earlier experiment Observations like Seed index (g) Seed Moisture Content (%) Electrical conductivity (µscm -1 ) Total dehydrogenase activity (TDH) Germination (%) Seedling vigour index I Seedling vigour index - II and Field emergence were recorded as the procedure described in the experiment Statistical analysis The mean experimental data was analysed by Fisher s method of Analysis of Variance (Sundararaj et al., 1972). All the observations recorded were subjected to F test, wherever, F test was found significant. The critical differences between the treatments were worked out at five per cent significance (Snedecor and Cochran, 1967). The data on percentage germination and field emergence were transformed into arc sine root percentage and the transformed data was used for statistical analysis.

61 Experimental Results

62 IV. EXPERIMENTAL RESULTS In the present study, the influence of different fruit maturity stages on seed quality, influence of different temperature and media on seed germination, influence of dormancy breaking treatment in seed germination, seedling length, seedling dry weight, seedling vigour index (I & II) and influence of papaya ring spot infected at different maturity stages on seed quality parameters of papaya ( Carica papaya L.). The results obtained during the course of investigation are presented in this chapter. 4.1 Determination of optimum maturity stage for harvesting papaya fruits for quality seeds. The data on influence of stage of fruit maturity on fruit weight, seed weight with sarcotesta, seed weight without sarcotesta and seed weight after drying are presented in Table Fresh fruit weight (g) Significant differences were seen in fruit weight due to different harvesting stages. The harvesting at compete yellow/orange stage recorded the maximum fruit weight T4 ( g) followed by after ripened complete yellow/orange stage T8 (732.55g), 1/2 yellow/orange stage T2 (692.15g), 1/4 th yellow/orange stage T1 (660.55g), after ripened 3/4 th yellow/orange stage T7(658.35g), after ripened 1/4 th yellow/orange stage T5 (656.25g), 3/4 th yellow/orange stage T3 (650.60g) and after ripened1/2 yellow/orange stage T6 which recorded the minimum with g of fruit weight Fresh seed weight with sarcotesta (g) There is significant difference in fresh seed weight with sarcotesta. It recorded the highest (80.38g) in T 4 complete yellow/orange stage of

63 Table 1. Influence of stage of fruit maturity on fresh fruit weight (g), fresh seed weight (g) with sarcotesta, fresh seed weight (g) without sarcotesta, and seed recovery (%) in papaya (Carica papaya L.) Treatments Fresh Fruit weight (g) Fresh Seed weight with sarcotesta (g) Fresh Seed weight without sarcotesta (g) Seed recovery (%) T T T T T T T T Mean SEm± CD (0.05) NS NS NS: Non significant Freshly harvested fruits T 1: 1/4 th yellow/orange T 2: 1/2 yellow/orange T 3: 3/4 th yellow/orange T 4: Complete yellow/orange Post harvest ripened fruits T 5: 1/4 th yellow/orange T 6: 1/2 yellow/orange T 7: 3/4 th yellow/orange T 8: complete yellow/orange

64 T1 T2 T3 T4 T5 T6 T7 T8 Maturity stages Fresh Fruit weight (g) fresh Seed weight with sarcotesta (g) Fig. 1. Influence of stage of fruit maturity on fresh fruit weight (g) and fresh seed weight with sarcotesta (g) in papaya ( Carica papaya L.) Seed index(g) seed moisture(%) 5 0 T1 T2 T3 T4 T5 T6 T7 T8 Fig. 2. Influence of stage of fruit maturity on seed index (g) and seed moisture (%) in papaya (Carica papaya L.) Freshly harvested fruits T 1: 1/4 th yellow/orangee T 2: 1/2 yellow/orange T 3: 3/4 th yellow/orange T 4: Complete yellow/orange Post harvest ripened fruits T 5: 1/4 th yellow/orange T 6: 1/2 yellow/orange T 7: 3/4 th yellow/orange T 8: complete yellow/orange

65 fruit harvest, whereas least fresh seed weight with sarcotesta (50.68 g) was noted in T6 after ripened 1/2 yellow/orange stage of fruit harvest Fresh seed weight without sarcotesta The fresh seed weight without sarcotesta showed highest (41.79 g) in the T8 after ripened complete yellow/orange stage whereas least (25.74 g) was observed in T6 after ripened1/2 yellow/orange stage and seed recovery percentage recorded highest in T7 after ripened 3/4 th yellow/orange stage(1.68%), and lowest in T4 complete yellow/orange stage(1.24%). However, there was no significant difference with respect to fresh seed weight without sarcotesta and dry seed weight of all stages of maturity Seed index (1000 seed weight) Maximum 1000 seed weight was recorded in T7 after ripened 3/4 th yellow/orange stage (16.49g) followed by T4 complete yellow/orange stage (16.37g), T2 1/2 yellow/orange stage (16.16g), T 6 after ripened1/2 yellow/orange stage(16.12g) which were on par with each other but significantly different from that of T3 3/4 th yellow/orange stage(15.85g), T1 1/4 th yellow/orange stage (15.46g), T 8 after ripened complete yellow/orange stage (15.44g), T5 after ripened 1/4 th yellow/orange stage (14.33g) as depicted in Table Moisture content (%) There is significant difference among the moisture content of seed of different maturity stages of fruit. It was the highest (20.31per cent) in T3 3/4 th yellow/orange stage followed by (15.18 per cent) in T4 complete yellow/orange stage and lowest (5.51 per cent) was found in T 7 after ripened 3/4 th yellow/orange stage shown in Table.2

66 Table 2. Influence of stage of fruit maturity on seed index (g), seed moisture (%), germination ( %), and fresh ungerminated seeds (%) in papaya (Carica papaya L.) Treatment Seed index (g) (1000 seed weight) Seed moisture (%) Germination (%) Fresh ungerminated seeds (%) T T T T T T T T (24.21) (28.11) (30.68) (46.43) (76.26) (49.64) (59.37) (61.73) (64.98) (60.25) (57.06) (40.36) (12.00) (34.44) (28.58) (25.76) Mean SEm± CD (0.05p) Freshly harvested fruits Post harvest ripened fruits T 1: 1/4 th yellow/orange T 5: 1/4 th yellow/orange T 2: 1/2 yellow/orange T 6: 1/2 yellow/orange T 3: 3/4 th yellow/orange T 7: 3/4 th yellow/orange T 4: Complete yellow/orange T 8: complete yellow/orange Figures in parentheses are arc sine transformed values

67 1/4th yellow/orange 1/2 yellow/ orange 3/4th yellow/orange 1/4th yellow/orange stage after ripened 1/2 yellow/orange stage after ripened 3/4th yellow/orange stage after ripened Plate 2. Influence of stage of fruit maturity on seed germination Complete yellow /orange Complete yellow/orange stage after ripened

68 4.1.6 Germination (%) Germination was highest (94.00%) in the seed ext racted after full ripening from the fruits harvested at T5 1/4 th yellow/orange stage and the least (21.50%) was in seed extracted soon after harvest from the fruits harvested at T1 1/4 th yellow/orange stage of fruit maturity. In freshly harvested fruits, T4 complete yellow/orange stage recorded maximum germination (52.50%) followed by T 3 3/4 th yellow/orange stage (26.50%), T 2 1/2 yellow/orange stage (22.50%), T 1 1/4 th yellow/orange stage (21.50%) being at par with T 3 3/4 th yellow/orange stage. In case of after ripened fruits, maximum germination was recorded in T5 1/4 th yellow/orange stage (94.00%) followed by after ripened T8 complete yellow/orange stage (77.50%), T 7 3/4 th yellow/orange stage (74.00%) and T 6 1/2 yellow/orange stage (58.00%). The statistical analysis revealed that there was significant difference on germination with respect to the fruit maturity stages as presented in Table Fresh ungerminated seeds (%) There is significant difference in presence of fresh ungerminated seeds in different stages of fruit maturity. The highest (77.50%) was found in T1 1/4 th yellow/orange and least (4.50%) was recorded in T 5 after ripened 1/4 th yellow/orange stage as dipicted in Table Seedling length (cm) The highest seedling length (14.46 cm) was recorded in T 2 1/2 th yellow/orange stage followed by (13.87cm) in T 3 3/4 th yellow/orange stage which was on par with T4 Complete yellow/orange stage (13.75cm) and T5 after ripened 1/4 th yellow/orange stage (13.67 cm) and least

69 (12.79 cm) seedling length in T7 after ripened 3/4 th yellow/orange stage. However, there was no statistically significant difference with respect to the seedling length and maturity stages of fruits presented in Table Seedling dry weight (mg) Non significant differences were recorded in seedling dry weight with respect to different maturity stages of fruits, however numerically higher(4.20mg) was recorded in T6 after ripened 1/2 th yellow/orange stage and lower (2.62) seedling weight in T 2 1/2 th yellow/orange stage dipicted in Table Vigour index Seedling vigour indexes I and II as influenced by different stages of fruit maturity showed significant differences. Higher vigour index (1286 and 391) was recorded in T5 after ripened 1/4 th yellow/orange stage followed by (945 and 307) in T 7 after ripened 3/4 th yellow/orange stage and least (318 and 61) were recorded in T 2 1/2 yellow/orange stage as depicted in Table 3. The data on influence of stage of fruit maturity on electrical conductivity (µscm -1 ), total dehydrogenase activity (A 480) and field emergence (%) of papaya (Carica papaya L.) are shown in Table Electrical conductivity (µscm -1 ) Lowest EC as shown in Table.4 recorded ( ) in the seed harvested at T4 Complete yellow/orange stage, followed by (0.1028) T8 after ripened complete yellow/orange stage which were on par with each other but significantly different from the (0.1280) T 6 after ripened 1/2 yellow/orange stage, (0.1310) T5 after ripened 1/4 th yellow/orange stage, (0.1683) T1 1/4 th yellow/orange stage, (0.1700) T7 after ripened 3/4 th

70 Table 3. Influence of stage of fruit maturity on seedling length (cm), seedling dry weight (mg), seedling vigour index -I and seedling vigour index-ii in papaya (Carica papaya L.) Treatment Seedling length (cm) Seedling dry weight (mg) Seedling vigour index-i Seedling vigour index -II T T T T T T T T Mean SEm± CD (0.05P) NS NS NS: Non significant Freshly harvested fruits T 1: 1/4 th yellow/orange T 2: 1/2 yellow/orange T 3: 3/4 th yellow/orange T 4: Complete yellow/orange Post harvest ripened fruits T 5: 1/4 th yellow/orange T 6: 1/2 yellow/orange T 7: 3/4 th yellow/orange T 8: complete yellow/orange

71 Table 4. Influence of stage of fruit maturity on EC (µscm -1 ), TDH (A480) and field emergence (%) in papaya (Carica papaya L.) Treatment EC (µscm -1 ) TDH (A480) Field emergence (%) T T T T T T T T (19.45) (21.37) (26.49) (43.86) (58.20) (44.23) (54.08) (45.78) Mean S.Em.± CD (0.05P) NS NS: Non significant Freshly harvested fruits Post harvest ripened fruits T 1: 1/4 th yellow/orange T 5: 1/4 th yellow/orange T 2: 1/2 yellow/orange T 6: 1/2 yellow/orange T 3: 3/4 th yellow/orange T 7: 3/4 th yellow/orange T 4: Complete yellow/orange T 8: complete yellow/orange Figures in parentheses are arc sine transformed values

72 yellow/orange stage, (0.1803) T3 3/4 th yellow/orange stage and (0.1893) T2 1/2 yellow/orange stage Total dehydrogenase activity (A480) Highest TDH activity was recorded in T4 Complete yellow/orange stage(1.2490), followed by (1.2046) T5 after ripened 1/4th yellow/orange stage and (1.1230) T 2 1/2 yellow/orange stage which were on par with each other and lowest(0.4426) was observed in T7 yellow/orange stage. after ripened 3/4 th Field emergence (%) The highest field emergence was recorded in T5 after ripened 1/4 th yellow/orange stage of fruit maturity (72.00%) followed by T 7 after ripened 3/4 th yellow/orange stage (65.30%), T8 after ripened complete yellow/orange stage(51.30%), T6 after ripened 1/2 yellow/orange stage(48.70%), T4 Complete yellow/orange stage (48.00%), T 3 3/4 th yellow/orange stage (20.0%) and T 2 1/2 th yellow/orange (13.30%) and least (12.00%) was recorded in T1 1/4 th yellow/orange stage. 4.2 Effect of temperature on seed quality of papaya (Carica papaya L.) The data on germination percentage, fresh ungerminated seeds, Speed of germination, Seedling length (cm), Seedling dry weight (mg), Vigour index I and II are depicted in Table Germination (%) Different temperatures influenced significantly the germination percentage. The seeds tested at T C registered maximum germination (89.00%) and it was significantly higher germination compared to the T C (81.50%) and T C (73.00%) alternate

73 T1 T2 T3 T4 T5 T6 T7 T8 germination (%) field emergence(%) Maturity stages Fig. 3. Influence of stage of fruit maturity on germination (% ) and field emergence (%) in papaya (Carica papaya L.) SVI SVII T1 T2 T3 T4 T5 T6 T7 T8 Fig. 4. Influence of stage of fruit maturity on seedling vigour indexpapaya I and seedling vigour index-ii in papaya (Carica L.) Freshly harvested fruits T 1: 1/4 th yellow/orangee T 2: 1/2 yellow/orange T 3: 3/4 th yellow/orange T 4: Complete yellow/orange Post harvest ripened fruits T 5: 1/4 th yellow/orange T 6: 1/2 yellow/orange T 7: 3/4 th yellow/orange T 8: complete yellow/orange

74 Table 5. Influence of different temperatures on seed quality parameters of papaya (Carica papaya L.) Treatment Germination (%) Fresh ungerminated seeds (%) Speed of emergence Seedling length (cm) Seedling dry weight (mg) Seedling vigour index-i Seedling vigour index-ii T1:20-30 C (64.57) (22.69) T3:20-35 C (58.80) (23.68) T2: C (71.30) (16.99) Mean S.Em.± CD (0.05p) Figures in parentheses are Arc sine transformed values

75 EC (µscm-1) T1 T2 T3 T4 T5 T6 T7 Maturity stages T8 Fig. 5. Influence of stage of fruit maturity on conductivity in papaya (Carica papaya L.) electrical Freshly harvested fruits T 1: 1/4 th yellow/orangee T 2: 1/2 yellow/orange T 3: 3/4 th yellow/orange T 4: Complete yellow/orange Post harvest ripened fruits T 5: 1/4 th yellow/orangee T 6: 1/2 yellow/orange T 7: 3/4 th yellow/orangee T 8: complete yellow/orange Germination (%) Spe eed of emergence germination 20 0 T1 T2 Treatments T3 Fig. 6. Influence of different temperatures on germination (%) and speed of germination (%) of papaya (Carica papaya L.) T 1: C T 2: :20-35 C T 3: C

76 Alternate temp C Alternate temp C Alternate temp C Plate 3. Influence of different temperature on seed quality parameters of papaya (Carica papaya L.)

77 temperature, and there was no result of germination in constant temperatures (20 C, 25 C, 30 C, and 35 C) Fresh ungerminated seeds (%) The seeds of papaya ( Carica papaya L.) tested at T C showed less fresh ungerminated seeds (9.00%) and it was significantly different compared tot C (15.00%) and T C(17.00%) Speed of germination The speed of germination was higher (48.56) at alternate temperature T C compared to T C (18.4 9) and lowest (15.54) at T C alternate temperature. However there were statistically significant differences with respect to different alternate temperatures Seedling length (cm) Seedling length was significantly the highest (19.52 cm) at T C alternate temperature followed by T C (15.89) and it was lowest (13.08) at T C Seedling dry weight (mg) Significant difference was observed in seedling dry weight. The highest (3.95 mg) was noticed in T C alternate temperature followed by T C (3.75 mg) and lowest (3.20mg) in T C Seedling vigour index-i Seedling vigour index-i was higher (1749) in T C followed by T C (1163) and lower (1066) was observed in T C. Statistically F value indicates a significant difference between the seedling vigour index-i and between alternate temperatures.

78 Seedling vigour index-ii There were significant differences in Seedling vigour index-ii highest (338) was o bserved at T C alternate temperature compared to (334) at T C and (235) at T C alternate temperatures The data on germination parameters as influenced by media and temperature are depicted in Table Germination (%) Germination was tested in different media (BP, sand coir pith, and TP) with different temperatures (T C, T C and T C). The mean germination percent was higher (85.75%) in sand followed by coir pith (85.35%), BP (81.16%) and TP (9.33% ). No significant difference was observed for the sand and coir pith. However significant difference was observed in BP and TP Speed of germination Speed of germination was tested in different media (BP, sand coir pith, and TP) with different temperatures (T C, T C and T C). Significant differences were observed in the mean speed of germination recorded highest (32.19) in sand media. It was superior over the BP (27.52), coir pith (19.52) and least was observed in TP (4.43) Seedling length (cm) Seedling length was tested in different media (BP, sand and coir pith,) with different temperatures (T C, T C and T C). The mean seedling length was highest (16.16cm) in BP than the sand (13.18cm) and coir pith (12.42cm). Significant difference was observed in between paper. However no significant difference was observed in BP sand and coir pith.

79 Table 6. Interaction of temperature and substrata on seed quality parameters of papaya ( Carica papaya L.) Treatment Germination (%) Speed of germination Seedling length (cm) BP Sand Coir pith TP BP Sand Coir pith TP BP Sand Coir pith T (64.50) (66.24) (72.78) (15.66) T (58.80) (62.05) (75.70) (12.56) T (71.30) (82.10) (49.64) (23.15) Mean SEm± CD (0.05p) NS NS NS NS NS: Non significant BP: Between paper TP: Top of paper T 1: C T 2:20-35 C T 3: C Figures in parentheses Are arc sine transformed values

80 Germination (%) T1: C T2: C T3:20-35 C BP Sand Treatments Coirpith Speed of emergence T1: C T2: C T3:20-35 C 5 BP Sand Treatments Coirpith Fig. 7. Interaction of temperature and substrata on germination (%) and speed of germination of papaya (Carica papaya L.)

81 Alternate temp C Media- BP Alternate temp C Media- BP Alternate temp C Media- BP Plate 4(a). Interaction of temperature (20-300C, C and C) and substrata (between paper) on seed quality parameters of papaya (Carica papaya L.)

82 0 Alternate temp C, Media- Sand 0 Alternate temp C, Media- coir pith 0 Alternate temp C, Media- Sand 0 Alternate temp C, Media- coir pith 0 Alternate temp C, Media- BP 0 Alternate temp C, Media- BP Plate 4(b). Interaction of temperature (20-300C, C and C) and substrata (sand and coir pith) on seed quality parameters of papaya (Carica papaya L.)

83 Alternate temp C Media- TP Alternate temp C Media- TP Alternate temp C Media- TP Plate 4(c). Interaction of temperature (20-300C, C and C) and substrata (top of paper) on seed quality parameters of papaya (Carica papaya L.)

84 Seedling dry weight (mg) Seedling dry weight was tested in different media (BP, sand and coir pith,) with different temperatures (T C, T C and T C). Mean seedling dry weight was the highest (3.82 mg) in sand followed by coir pith (3.70mg) and BP (3.63mg). No significant difference was observed in sand and coir pith. However, significant difference was observed in BP are presented in table Seedling vigour index-i Mean seedling vigour index-i was the highest (1326) in BP followed by sand (1126) and lowest (1061) was observed in coir pith. No Significant difference was observed in sand and coir pith, however significant difference was observed in BP as indicated in table Seedling vigour index-ii The highest mean seedling vigour index II was recorded in sand (328) compared to coir pith (317) and BP (302). Significant difference was observed in BP. However no Significant difference was observed in sand and coir pith. 4.3 Effect of dormancy breaking treatment on seed quality of papaya (Carica papaya L) The data on seed quality parameters as influence by GA3 treatment are depicted in Table 8(a) Germination percentage The data on germination percentage as influenced by seed treated with GA3 at different concentrations (T4 100ppm, T3 200ppm, T2 300ppm & T1 400ppm) for different durations (D 1 12h, D2 24h, D3 36h and D4 48h) are depicted in Table.8

85 Table 7. Interaction of temperature and substrata on seedling dry weight (mg), seedling vigour index-i and seedling vigour index-ii in papaya (Carica papaya L.) Treatment Seedling dry weight (mg) Seedling vigour index-i Seedling vigour index-ii BP Sand Coir pith BP Sand Coir pith BP Sand Coir pith T T T Mean SEm± CD (0.05p) 0.45 NS NS NS NS NS NS NS: Non significant BP: Between paper TP: Top of paper T 1: C T 2:20-35 C T 3: C

86 SVIl T1 T2 T BP Sand Treatments Coir pith SVII T1 T2 T3 0 BP Sand Treatments Coir pith Fig. 8. Seedling vigour index-i and seedling vigour index-ii as influenced by substrata and temperature in papaya (Carica papaya L.) T 1: C T 2: :20-35 C T 3: 25-35

87 Table 8(a).Seed quality as influence by the interaction of GA3 (T) and Duration (D) in papaya ( Carica Treatment T1 T2 T3 T4 T5 papaya L.) Germination (%) Fresh ungerminated seeds (%) D1 D2 D3 D4 Mean D1 D2 D3 D4 Mean (69.10) (74.80) (66.50) (73.40) (59.74) (72.90) (70.22) (67.86) (70.60) (60.07) (68.15) (68.20) (63.13) (75.05) (53.28) (71.2) (68.7) (66.4) (69.8) (53.18) (19.92) (14.48) (19.11) (15.77) (27.49) (15.14) (19.47) (16.66) (13.01) (27.78) (17.32) (17.12) (19.11) (14.94) (33.29) (13.22) (17.80) (17.89) (16.16) (33.58) Mean SEm± CD (0.05P) SEm± CD (0.05P) T D 1.09 NS 1.08 NS TxD 2.44 NS 2.42 NS T 1: GA 400ppm, D 1: 12h T 2: GA 300ppm, D 2: 24h T 3: GA 200ppm D 3: 36h, T 4: GA 100ppm D 4: 48h, T 5: CONTROL T D = Treatment Duration Figures in parentheses are Arc sine transformed values

88 ppm 12 h soaking GA3@400 ppm 24 h soaking GA3@300 ppm 12 h soaking GA3@300 ppm 24 h soaking GA3@200 ppm 12 h soaking GA3@200 ppm 24 h soaking GA3@200 ppm 12 h soaking GA3@100 ppm 24 h soaking Plate 5(a). Seed quality as influenced by interaction of GA3 and duration in papaya (Carica papaya.l)

89 ppm 36 h soaking GA3@400 ppm 48 h soaking GA3@300 ppm 36 h soaking GA3@300 ppm 48 h soaking GA3@200 ppm 36 h soaking GA3@200 ppm 48 h soaking GA3@100 ppm 36 h soaking GA3@100 ppm 48 h soaking Plate 5(b). Seed quality as influenced by interaction of GA3 and duration in papaya (Carica papaya.l)

90 Increase in seed germination percentage was recorded in all the treatments compared to untreated control. The mean seed germination registered maximum (90.00%) when treated with T4 GA3 at 100ppm followed by the T1 GA3 at 400ppm & T2 300ppm, (88.50 %, 88.25%). However minimum increase (82.75%) was observed in treatment T3 GA3 200ppm. The interaction between T2D1 GA3 at 300ppm and 12 h duration recorded higher germination (93.00%) which is on par with the T4D3 GA3 at 100ppm in the 36h duration. Significant differences were observed with respect to germination due to treatments. Non significant differences were observed in the treatment and durations interactions Fresh ungerminated seeds Less mean fresh ungerminated seeds were recorded in T4 GA3 100ppm (7.50%) followed by T 2 GA3 at 300ppm (8.30%) and maximum fresh ungerminated seeds observed in untreated control. The interaction between T1D4 GA3 at 400 ppm and 48 h duration recorded less fresh ungerminated seeds (5.50%) followed by the T4D2, T4D3, GA3 at 100ppm (7.00%) in the 24h and 36h durations. Significant differences were observed with respect to germination due to treatments. Non significant differences were observed in the interaction of treatments and durations Seedling length (cm) Seedling length differed significantly in treatments and treatment and duration interactions. The results are presented in the Table.9 The mean maximum seedling length was recorded when treated with T1 GA3 at 400ppm (14.08cm) followed by the T 5 untreated control

91 Table8(b). Treatment Seed quality as influence by the interaction of GA3 (T) and Duration (D) in papaya ( Carica papaya L.) Seedling length(cm) Seedling dry weight(mg) D1 D2 D3 D4 Mean D1 D2 D3 D4 Mean T T T T T Mean SEm± CD (0.05p) SEm± CD (0.05p) T D 0.25 NS 0.05 NS T x D NS: Non significant T 1: GA 400ppm, D 1: 12h T 2: GA 300ppm, D 2: 24h T 3: GA 200ppm D 3: 36h, T 4:GA 100ppm D 4: 48h, T 5: CONTROL T D = Treatment Duration

92 100 Germination (%) T1 T2 T3 T4 T5 Treatments D1: 12h D2: 24h D3: 36h D4: 48h 18 Seedling length (cm) T1 T2 T3 T4 T5 D1: 12h D2: 24h D3: 36h D4: 48h Treatments Seedling dry weight(mg) T1 T2 T3 T4 T5 Treatments D1: 12h D2: 24h D3: 36h D4: 48h Fig. 9. Germinationn (%), seedling length ( cm) and seedling dry weight (mg) influenced by the interaction of GA33 (T) Duration (D) in papaya (Carica papaya L.) T 1: GA 400ppm T 2: GA 300ppm T 3: GA 200ppm T 4:GA 100ppm T 5: CONTROL

93 (13.80cm) and T2 GA3 at 300ppm (13.01cm) which were on par with each other and minimum was observed in T3 GA3 at 200ppm (12.40cm). Among durations the highest (13.60cm) seedling length was observed in D3 36h soaking and lowest (12.80cm) was recorded in D 1 12 h duration soaking. Maximum seedling length was observed in the T5D3 untreated control at 36 h duration soaking (16.85cm) followed by T 5D1 untreated control at 12 h duration soaking (14.15cm) and T1D2 GA3 at 400 ppm at 24 h duration soaking (14.31cm). Minimum seedling length was observed in T5D4 untreated control at 48 h duration soaking (11.26 cm) Seedling dry weight (mg) Data on effect of treatments and duration on seedling dry weight are presented in Table 8(b) Significant difference with respect to seedling dry weight was observed both in treatments and treatment and duration interactions. The mean highest seedling dry weight was recorded when treated with T1 GA3 400ppm (4.04mg) followed by the GA3 at (T2 300ppm, T3 200ppm and T4 100ppm) (3.98mg, 3.91mg and 3.86mg) when compared to T5 untreated control (3.68mg). The mean seedling dry weight was maximum in D3 36 h soaking (3.99mg) and minimum in D4 48 h soaking (3.82mg) Among the interactions T1D1 GA3 at 400ppm for 12 h duration recorded highest (4.10mg) followed by T1D2, T1D3 & T1D4 GA3 at 400ppm for 24h, 36h and 48h duration (4.00mg) and least was recorded in T 5D4 untreated control at 48h soaking (3.40mg).

94 Seedling vigour index-i The mean seedling vigour index I differed significantly and recorded highest vigour index in seeds treated with T1 GA3 at 400ppm (1339) compared to other treatments and least was observed in T5 untreated control (952) The seeds of papaya treated for D1 12 h duration registered maximum mean seedling vigour index-i (1174) which was superior over D2 24h, D3 36h and D4 48h. The interaction between T1D1 GA3 at 400ppm for 12h duration recorded higher seedling vigour index I (1566) and lower (713) in T 5 D4 untreated control with 48 h soaking in water. However, non significant difference was indicated in duration and interaction (treatments and durations) are presented in table Seedling vigour index-ii The seedling vigour index-ii was significantly higher (357) in T 1 GA3 at 400ppm followed (352) by T2 GA3 at 300ppm which was on par with each other compared to other treatments. Among the durations, the seedling vigour index-ii at D2 24 h recorded higher (334) and lowest at D4 48 h treatment (317). Among interactions the seedling vigour index -II was significantly the highest (393) in seeds treated with T 4D3 GA3 at 100ppm for 36 h whereas lowest in T5D4 untreated control with 48 h water soaking (219).However non significant difference was noticed in durations are presented in table Field emergence (%) The data on field emergence as influence by GA3 concentrations at different durations are indicated in Table 9. The field emergence was significantly higher (76.90%) in treatment T1 GA3 at 400ppm and T2 GA3 at 300ppm followed by T4 GA3 at 100ppm

95 Table 9. Influence of GA3 on seedling vigour index-i, seedling vigour index-ii and field emergence(%) of papaya seed (Carica papaya L.) Treatment Seedling vigour index-i Seedling vigour index-ii Field emergence (%) D1 D2 D3 D4 Mean D1 D2 D3 D4 Mean D1 D2 D3 D4 Mean T (66.52) (57.28) (64.22) (59.88) T (62.43) (61.17) (60.34) (62.51) T (61.98) (56.85) (62.09) (60.75) T (62.51) (57.58) (58.38) (65.83) T (54.75) (55.97) (51.97) (50.77) Mean SEm± CD (0.05p) SEm± CD (0.05p) SEm± CD (0.05p) T D NS NS NS TxD NS NS NS: Non significant T 1: GA 400ppm D 1: 12h T 2: GA 300ppm D 2: 24h T 3: GA 200ppm D 3: 36h T 4:GA 100ppm D 4: 48h T 5: CONTROL T D = Treatment Duration

96 2000 Vigour index-i T1 T2 T3 T4 T5 Treatments D1: 12h D2: 24h D3: 36h D4: 48h 400 Vigour index-ii T1 T2 T3 T4 T5 Treatments D1: 12h D2: 24h D3: 36h D4: 48h Field emergence(%) T1 T2 T3 T4 T5 Treatments D1: 12h D2: 24h D3: 36h D4: 48h Fig. 10. SVI, SVIII and field emergence (%) influence by the interactionn of GA3 papaya L..) (T) Duration (D) in papaya ( Carica T 1: GA 400ppm T 2: GA 300ppm T 3: GA 200ppm T 4:GA 100ppm T 5: CONTROL

97 (74.70%). Among durations, D1 12 h soaking registered maximum (76.90%) compared to other. Among interactions, seeds treated with T1 D1 GA3 at 400ppm for 12 h recorded highest field emergence (84.00%). It was low (60.00%) in T5 D4 untreated control with 48 h soaking in water The data on seed quality parameters as influence by treatment KNO3 are depicted in Table 10(a) Germination percentage The data on germination percentage as influenced by seed treated with KNO3 at different concentrations (T 1 2%, T2 1.5%, T3 1% and T4 0.5%) for different durations (D 1 12h, D2 24h, D3 36h and D4 48h) are depicted in Table.10(a) Increase in seed germination percentage was recorded in all the treatments compared to untreated control. The mean seed germination registered maximum (83.00%) when treated with T1 KNO3 2% followed by the T3 KNO3 at 1% & T2 1.5% (82.00% & 81.90%). However minimum (78.00%) was observed in treatment T4 KNO3 0.5%. Among durations, seed germination was higher (79.80%) in D2 24 h soaking followed by D1 12 h soaking (79.20%) which is on par with each other compared to other. The interaction between T1 D2 KNO3 at 2% treatments and 24 h duration recorded higher germination (91.00%) and least was observed in T5D3 and T5D4 untreated control with 36 and 48 h soaking in water (64.00%). Significant differences were observed with respect to germination due to treatments and treatment duration interactions. No significant differences were observed in the duration.

98 Table 10(a). Interaction effect of KNO3 Treatment T1 T2 T3 T4 T5 (Carica papaya L.) and duration on seed quality parameters of papaya seed Germination (%) Fresh ungerminated seeds (%) D1 D2 D3 D4 Mean D1 D2 D3 D4 Mean (63.50) (72.90) (70.26) (58.60) (23.15) (11.75) (15.24) (22.40) (66.28) (69.49) (64.34) (60.41) (18.41) (2.88) (20.66) (25.05) (64.55) (61.70) (65.02) (69.68) (21.90) (09.83) (18.91) (11.19) (61.77) (55.71) (61.35) (71.28) (19.54) (07.08) (16.10) (14.29) (59.74) (60.07) (53.28) (53.18) (27.49) (27.08) (33.29) (33.58) Mean SEm± CD (0.05p) SEm± CD (0.05p) T D 0.99 NS T x D NS: Non significant T 1: KNO 2% D 1:12 h T 2: KNO 1.5% D 2: 24h T 3: KNO 1% D 3:36 h T 4: KNO 0.5% D 4: 48 h T 5: CONTROL T D = Treatment Duration Figures in parentheses are Arc sine transformed values 26.40

99 12 h soaking KNo3@2% 24 h soaking KNo3@1.5% 12 h soaking KNo3@1.5% 24 h soaking KNo3@1% 12 h soaking KNo3@1% 24 h soaking KNo3@0.5% 12 h soaking KNo3@0.5% 24 h soaking Plate 6(a). Seed quality as influenced by interaction of KNO3 and duration in papaya (Carica papaya.l)

100 KNo 36 h soaking KNo 36 h soaking KNo 36 h soaking KNo 36 h soaking KNo h soaking KNo h soaking KNo h soaking KNo h soaking Plate 6(b). Seed quality as influenced by interaction of KNO3 and duration in papaya (Carica papaya.l)

101 Fresh ungerminated seed Mean fresh ungerminated seeds were less in T4 KNO3 0.5% (7.30%) followed by T3 KNO3 at 1% (8.60%) and maximum fresh ungerminated seeds observed in untreated control. Among duration, the least (6.90%) fresh ungerminated seeds were observed in D2 24 h soaking and maximum (15.50%) was recorded ind4 48 h soaking. The interaction between treatment T2D2 KNO3 at 1.5% and 24 h duration recorded less fresh ungerminated seeds (1.00%) followed by the treatment T3D2 & T4D2 KNO3 at 1% and 0.5% (3.00%) in the 24h duration. Significant differences were observed with respect to germination due to treatments, duration and treatment duration interactions Seedling length (cm) Seedling length differed significantly in treatments, durations and treatment and duration interactions. The results are presented in the table 10(b) The mean seedling length was maximum T5 untreated control (13.80cm) followed by the T1 KNO3 at 2% and T3 1% (12.30cm) which is on par with each other and minimum was observed in T4 KNO3 at 0.5% (11.70cm) and among durations it is significantly highest (13.50cm) in D3 36 h and least in D2 24h soaking (10.90cm). Maximum increase in seedling length was observed in the T5D3 untreaed control at 36 h duration soaking (16.85 cm) followed by T 5D1 untreated control at 12 h duration soaking (14.15 cm) and Minimum seedling length was observed in T5D4 untreated control at 48 h duration soaking (11.26 cm)

102 Table 10(b).Interaction effect of KNO3 and duration on seed quality parameters of papaya seed (Carica papaya L.) Treatment Seedling length (cm) Seedling dry weight (mg) D1 D2 D3 D4 Mean D1 D2 D3 D4 Mean T T T T T Mean SEm± CD (0.05p) SEm± CD (0.05p) T D NS T x D NS: Non significant T 1: KNO 2% D 1:12 h T 2: KNO 1.5% D 2: 24h T 3: KNO 1% D 3:36 h T 4: KNO 0.5% D 4: 48 h T 5: CONTROL T D = Treatment Duration

103 100 Germination (%) D1: 12h D2: 24h D3: 36h D4: 48h 50 T1 T2 T3 T4 T5 Treatments 18 seedling length (cm) T1 T2 T3 T4 T5 Treatments D1: 12h D2: 24h D3: 36h D4: 48h Seedling dry weight (mg) T1 T2 T3 T4 T5 Treatments D1: 12h D2: 24h D3: 36h D4: 48h Fig. 11. Interactionn effect of KNO3 and duration on seed germination, seedling length (cm) and seedling dry weight (mg) of papaya seed (Carica papaya L.) T 1: KNO 2% T 2: KNO 1.5% T 3: KNO 1% T 4: KNO 0.5% T 5: CONTROL

104 Seedling dry weight (mg) Data on effect of treatment and duration on seedling dry weight are presented in Table.10(b) Significant difference with respect to seedling dry weight was observed both in treatments and treatment and duration interactions The highest seedling dry weight was recorded when treated with the T1 KNO3 2% (4.01g) followed by the T2 KNO3 1.5%, T4 0.5% and T3 1% (3.97mg, 3.89mg and 3.88mg) when compared to T5 untreated control (3.69mg). Among durations the highest seedling dry weight was observed in D1 12 h soaking (3.94mg) and least (3.81mg) in D2 24h. The interaction between T4D4 KNO3 0.5% and 48 h duration recorded highest seedling dry weight (4.15 mg) followed T1D3, T1D1, T1D2 KNO3 2%, at 36 h, 12h and 24h and duration (4.05mg, 4.02mg and 4.00 mg) and least was recorded in T5D4 untreated control at 48h soaking (3.40 mg) Seedling vigour index-i The mean seedling vigour index I differed significantly and it recorded highest (1020) in seed treated with T1 KNO3 2%, compared to other treatments and least (921) was observed in T 4 KNO3 0.5%, untreated control depicted in table.11 The seeds of papaya treated for D3 36 h duration registered maximum mean seedling vigour index-i (1048) which was superior over D4 48h (992), D1 12h (986) and D2 24h (872). The interaction between T3 D4 KNO3 at 1% with 48 h recorded higher seedling vigour index I (1212) and lower (678) in T4D2 KNO3 at 0.5% with 24 h soaking. However significant differences were indicated in duration and interaction (treatment and duration)

105 Table 11. Influence of KNO3 on seedling vigour index-i, seedling vigour index-ii and field emergence (%) of papaya seed (Carica papaya L.) Treatment Seedling vigour index-i Seedling vigour index-ii Field emergence (%) D1 D2 D3 D4 Mean D1 D2 D3 D4 Mean D1 D2 D3 D4 Mean T (60.12) (60.37) (56.56) (55.75) T (60.27) (61.58) (60.75) (56.39) T (56.77) (56.95) (60.76) (62.09) T (60.00) (56.88) (58.59) (56.11) T (54.75) (55.57) (51.97) (50.77) Mea n SEm± CD (0.05P) SEm± CD (0.05P) SEm± CD (0.05P) T NS NS D NS NS T x D NS NS: Non significant T 1: KNO 2% D 1:12 h T 2: KNO 1.5% D 2: 24h T 3: KNO 1% D 3:36 h T 4: KNO 0.5% D 4: 48 h T 5: CONTROL T D = Treatment Duration Figures in parentheses are Arc sine transformed values

106 SVI T1 T2 T3 T4 T5 Treatments D1: 12h D2: 24h D3: 36h D4: 48h 400 SVII T1 T2 T3 T4 T5 Treatments D1: 12h D2: 24h D3: 36h D4: 48h Field emergence (%) T1 T2 T3 T4 T5 Treatments D1: 12h D2: 24h D3: 36h D4: 48h Fig. 12. Interactionn effect of KNO3 and duration on SVI, SVII and field emergence (%) of papaya seed (Carica papaya L.) T 1: KNO 2% T 2: KNO 1.5% T 3: KNO 1% T 4: KNO 0.5% T 5: CONTROL

107 Seedling vigour index-ii The mean seedling vigour index-ii depicted in table.13 and it was significantly higher in T1 KNO3 2% (333) followed by T2 KNO3 1.5 % (325) compared to other treatments. Among the durations, the seedling vigour index-ii at D1 12 h recorded highest (311) and it was lowest at D 4 48 h treatment (303). Among interactions the seedling vigour index -II was significantly the highest in seeds treated with T4D4 KNO3 0.5% for 48h (371) whereas lowest in T5D4 untreated control with 48 h water soaking (216).However difference was not significant in durations Field emergence (%) The data on field emergence as influenced by KNO3 concentrations at different durations are indicated in table 11 The field emergence was significantly higher (73.90%) in treatment T2 KNO3 1.5%, and T3 KNO3 1%, which is on par with each other followed by T1 KNO3 2%, and T4 0.5 % (71.80% and 71.50%). Among durations, D1 12 h and D2 24 h soaking registered maximum (71.90 and 71.80%) which is on par with each other, and superior over to other treatment. Among interactions, seeds treated with KNO3 T2D2 1.5%, for 24 h and T3D4 1%, for 48h recorded the highest field emergence (77.3%) which is on par with each other. It was lowest (60.00%) in T5D4 untreated control with 48 h soaking in water The data on seed quality parameters as influence by treatment with Azotobacter chrococcum (5g/kg of seed) are depicted in Table Germination (%) The germination rate has increased with the seed treatment of

108 Table 12. Influence of Azotobacter chrococcum on Seed quality parameters of Papaya (Carica papaya L.) Treatments A.chro. 5D A.chro.10D A.chro.15D A.chro.20D Control Germination (%) (66.82) (63.90) (65.64) (74.39) (46.43) Fresh ungerminated seeds (%) (21.12) (23.03) (22.73) (12.56) (40.36) Seedling length(cm) Seedling dry weight(mg) Seedling vigour index-i Seedling vigour index-ii Field emergence (%) (61.86) (58.60) (59.48) (64.75) (43.86) Mean SEm± CD (0.05p) NS NS NS NS NS: Non significant Figures in parentheses are arc sine transformed values

109 Germination (%) FUS(%) Field emergence(%) A.chro. 5D A.chro.10D A.chro.15D A.chro.20D Control Treatments vigour index-i vigour index-ii A.chro. 5D A.chro.10D A.chro.15D A.chro.20D Control Treatments Fig. 13. Influence of Azotobacter chrococcum on seed quality parameters of papaya (Carica papaya L.)

110 A.chrococcum treated seeds A. chrococcum, 5 days A. chrococcum, 10 days A. chrococcum, 15 days A. chrococcum, 20 days Plate 7. Influence of Azotobacter chrococcum on seed for different durations on seed quality parameters of papaya ( Carica papaya L.)

111 Azotobacter chrococcum.significant difference in germination percentage was highest (92.50%) in seed treated with Azotobacter chrococcum for 20 days followed by Azotobacter chrococcum 5 days (84.50%) while minimum (52.50%) germination rate was observed in untreated control Fresh ungerminated seeds (%) There is significant difference in fresh ungerminated seeds. The lowest (5.00%) was observed in seed treated with Azotobacter chrococcum for 20 days and higher (42.00%) was observed in untreated control Seedling length (cm) The highest seedling length (15.28cm) was observed in seeds treated with Azotobacter chrococcum for 5 days followed by Azotobacter chrococcum treatment 20 and 10 days (14.99 and 14.55cm) which are on par with each other and least (13.75cm) was in untreated control. However, there was no significant difference with respect to seedling lengths Seedling dry weight (mg) The seedling dry weight was highest (4.17mg) in seed treated with Azotobacter chrococcum for 5 days and least (3.55mg) was observed in untreated control. However, non significant difference was observed in seedling dry weight Seedling vigour index-i There is significant difference in seedling vigour index-i which was maximum (1387) SVI in seeds treated with Azotobacter chrococcum for 20 days and minimum (732) was recorded in untreated control

112 Seedling vigour index-ii There is no significant difference in Seedling vigour index-ii. The higher (352) SVII was recorded in seed treated with Azotobacter chrococcum for 5 days and lower (187) in untreated control Field emergence (%) Field emergence was found to be higher in the seeds treated with Azotobacter chrococcum for 20 days (81.33%) and lower in untreated control seeds. Statistically,there was no significant difference in the field emergence The data on seed quality parameters as influence by hot water soaking at 50 C for different duration are depicted in Table Germination (%) Significant difference in germination percentage was highest (78.00%) in seed soaked in hot water at 50 C for 45 minutes while minimum (48.00%) germination rate was observed in 10 minutes treatment and untreated control showed higher germination rate Fresh ungerminated seeds There is significant difference in fresh ungerminated seeds. The lowest (17.00%) was observed in 45 minutes treatment and higher (48.00%) was observed in 10 minutes treatment Seedling length (cm) There is significant difference in seedling length. The highest seedling length was observed in seed soaked for 20 minutes in hot water at 50 C (14.64cm) followed by untreated control (13.75 cm) and seed soaked for 10 minutes (12.84cm), 45 minutes (12.45 cm) and 30 minutes (12.08 cm) which is on par with each other.

113 Table 13. Influence of hot water soaking at 50 C for different durations on seed quality parameters of Papaya (Carica papaya L.) Treatments Hot water soaking 10 min Hot water soaking 20min Hot water soaking 30min Hot water soaking 45min Control Germination (%) (43.79) (48.49) (56.93) (62.50) (46.43) Fresh ungerminated seeds (%) (43.85) (37.44) (27.10) (24.32) (40.36) Seedling length (cm) Seedling dry weight (mg) Seedling vigour index-i Seedling vigour index-ii Field emergence (%) (38.04) (42.21) (48.46) (50.38) (43.86) Mean S.Em.± CD (0.05p) NS NS NS: Non significant Figures in parentheses are arc sine transformed values

114 Germination (%) FUS(%) 10 0 Hot water soaking 10 min Hot water soaking 20min Hot water soaking 30min Hot water soaking 45min Control Treatments vigour index-i vigour index-ii Hot water soaking 10 min Hot water soaking 20min Hot water soaking 30min Treatments Hot water soaking 45min Control Fig. 14. Influence of hot water soaking at 50 C for different durations on seed quality parameters of papaya (Carica papaya L..)

115 Hot 10 M Hot 20 M Hot 30 M Hot 45 M Plate 8. Influence of hot water soaking at 50 C for different durations on seed quality parameters of papaya (Carica papaya L.)

116 Control 12 h soaking Control 24 h soaking Control 36 h soaking Plate 9. Seed quality as influenced control (seed soaking at different duration) Control 48 h soaking

117 Seedling dry weight (mg) The seedling dry weight was highest in seed soaked for 20 minutes (4.22mg) and least was observed in untreated control (3.55mg). However no significant difference was observed in seedling dry weight and treatment Seedling vigour index-i There is significant difference in seedling vigour index I. The maximum SVI was observed in seeds soaked for 45 minutes in hot water (969) and minimum in 10 minutes treatment (611) Seedling vigour index-ii Significant difference in Seedling vigour index-ii is higher SVII was recorded in seed soaked in hot water at 50 C for 45 minutes (304) and lowest (181) was noted in 10 minutes treatment Field emergence (%) Field emergence was found to be higher in seeds soaked for 45 minutes (59.33%) and lowest in 10 minutes treatment (38.67%). 4.4 Effect of different ring spot infected fruits stages on quality of seeds The data Influence of stage of fruit maturity on fruit weight, seed weight with sarcotesta, seed weight without sarcotesta, and Seed recovery (%) of ring spot infected fruit of papaya are depicted in Table Fruit weight (g) Non significant differences were recorded in fruit weight when harvested at T5 control (compete yellow /orange stage without infection) which recorded the maximum fruit weight (593.33g) followed by T 3 3/4 th

118 Table 14. Influence of stage of fruit maturity on fresh fruit weight (g), fresh seed weight (g) with sarcotesta, fresh seed weight (g) without sarcotesta, and seed recovery (%) of ring spot infected fruit of papaya (Carica papaya L.) Treatments Fruit weight (g) Fresh seed weight with sarcotesta (g) Fresh seed weight without sarcotesta (g) Seed recovery (%) T T T T T Mean SEm± CD (0.05p) NS NS NS: Non significant T 1: 1/4th yellow/orange T 2:1/2th yellow/orange T 3: 3/4th yellow/orange T 4: complete yellow/orange T 5: Control (complete yellow/orange)

119 1/4 th yellow/ orange stage 1/2 yellow/ orange stage 3/4 th yellow/ orange stage Complete yellow/ orange stage Complete yellow/ orange stage 1/4 th yellow/orange stage 1/2 yellow/orange stage 3/4 th yellow/orange stage Complete yellow/orange stage Plate 10. Different fruit maturity stages with ring spot infection

120 yellow/orange stage (574.17g) and T 1 1/4 th yellow/orange stage (507.83g), and least weight in T4 compete yellow/orange stage (412.33g) Fresh Seed weight with sarcotesta (g) There is no significant difference in fresh seed weight with sarcotesta which recorded numerically more (40.84g) in T 5 control (compete yellow/orange stage without infection), whereas less fresh seed weight with sarcotesta (23.38g) was noted in T4 compete yellow/orange stage Fresh seed weight without sarcotesta (g) Significant difference was observed among the fresh seed weight without sarcotesta which showed highest in the T5 (complete yellow/orange stage without infection) control (19.65g) whereas least in T4 complete yellow/orange stage (5.16g) Seed recovery percentage Seed recovery percentage recorded the highest in the T1 yellow/orange stage (1.72%) and lowest (0.57%) in T 4 complete yellow/orange stage. However there was statistically non significant difference with respect to the dry seed weight of all stages of maturity. The data influence of ring spot infection at fruit maturity stages on seed index (g), seed moisture content (%), electrical conductivity (ds/m -1 ), total dehydrogenase activity, germination (%), fresh ungerminated seeds (%) and field emergence (%) as depicted in Table Seed index (g) There was significant difference in 1000 seed weight. The maximum was recorded in T1 1/4 th yellow/orange stage (15.56g) followed by T3 3/4th yellow/orange stage (15.26g), T 2 1/2 yellow/orange stage

121 (14.17g), T5 control (complete yellow/orange stage without infection) (13.82g) and least (13.37g) is observed in T 4 complete yellow/orange stage are shown in table Seed moisture content (%) There is significant difference among the moisture content of seed of different maturity stages of ring spot infected fruits was observed the highest (53.18 per cent) in T 5 control (complete yellow/orange stage without infection) followed by (30.49 per cent) in T4 Complete yellow/orange stage and lowest (3.77 per cent) in 1 /4 th yellow/orange stage are presented in table Germination (%) Germination was significantly higher in the seed extracted at T1 1/4 th yellow/orange stage(80.00 %), followed in T5 (control) complete yellow/ orange stage by without infection (78.00%) and the least was in seed extracted from the fruits harvested at T2 1/2 yellow/orange stage (15.00 %) of ring spot infected fruits at maturity as depicted in table Fresh ungerminated seeds (%) There was significant difference in fresh ungerminated seeds in different stages of fruit maturity. The lowest value was found in T1 1/4 th yellow/orange (12.25%) and highest was recorded in T2 1/2 yellow/orange stage (81.25 %) as indicated in table Seedling length (cm) Seedling length did not differ statistically but it was numerically higher (14.34cm) in T 1 1/4th yellow/orange stage followed by T3 3/4th yellow/orange stage 12.83cm, T4 complete yellow/orange stage 12.57cm and T5 complete yellow/orange stage without infection (control) 12.10cm

122 Table 15. Influence of ring spot infection at fruit maturity stages on seed quality parameters of papaya (Carica papaya L.) Treatment Seed Index (g) Seed moisture (%) Germination (%) Fresh ungerminated seeds (%) Seedling length (cm) Seedling dry weight (mg) T (65.17) (19.01) T (16.59) (70.21) T (24.66) (62.01) T (30.82) (56.74) T (62.99) (22.31) Mean S.Em.± CD (0.05P) NS 1.66 NS: Non significant T 1: 1/4 th yellow/orange T 2:1/2 yellow/orange T 3:3/4 th yellow/orange T 4: complete yellow/orange T 5: Control Figures in parentheses are arc sine transformed values

123 seed index (g) Seed moisture(%) 0 T1 T2 T3 Maturity satages T4 T5 Fig. 15. Influence of ring spot infection at fruit maturity stages on seed index (g) and seed papaya L..) moisture (%) in papaya ( Carica Germination (%) Field emergence(%) T1 T2 T3 T4 T5 Treatments Fig. 16. Influence of ring spot infection at fruit maturity stages on seed germination (%) and field emergence (%) in papaya (Carica papaya L.) T 1: 1/4 th yellow/orangee T 2:1/2 yellow/orange T 3:3/4 th yellow/orangee T 4: complete yellow/orange T 5: Control

124 1/4th yellow/orange stage with PRSV infection 1/2 yellow/orange stage with PRSV infection Complete yellow/orange stage with PRSV infection 3/4th yellow/orange stage with PRSV infection Control (without infection) Plate 11. Influence of ring spot infected fruit maturity stage on seed quality parameters of papaya (Carica papaya L)

125 which were on par with each other. The least was observed in T2 1/2 yellow/orange stage (6.45cm) are presented in table Seedling dry weight (mg) Significantly highest seedling dry weight was recorded in T4 complete yellow/orange stage (3.9mg) and least in T 2 1/2 yellow/orange stage (1.8mg). The data Influence of ring spot infection at fruit maturity stages on seedling vigour index-i & II, electrical conductivity (µscm -1 ), total dehydrogenase activity and field emergence (%) are depicted in Table Seedling vigour index-i Seedling vigour index as influenced by ring spot infected fruit maturity showed significant differences. Highest seedling vigour index I was recorded in T1 1/4 th yellow/orange stage (1137) and least was noted in T2 1/2 yellow/orange stage (194) Seedling vigour index-ii The statistical analysis revealed that there was significant difference among seedling vigour index-ii of maturity stages of ring spot infected fruits. Highest seedling vigour index-ii was observed in T1 1/4 th yellow/orange stage (290) followed b y T5 ( control) Complete yellow/orange stage without infection (286) and lowest in T2 1/2 yellow/orange stage (55) Electrical conductivity (µscm -1 ) There was statistically significant difference with respect to the Electrical conductivity (µscm -1 ) and maturity stages of ring spot infected fruits. Lowest EC was recorded in the seed harvested at T4 Complete yellow/orange stage (0.1460), followed by T2 1/2 yellow/orange stage

126 Table 16. Influence of ring spot infected fruit maturity stages on seedling vigour index-i, seedling Treatment vigour index II, electrical conductivity (µscm -1 ), total dehydrogenase activity (A480) and field emergence (%) in papaya (Carica papaya L.) Seedling vigour index-i Seedling vigour index-ii EC (µscm -1 ) TDH (A480) T T T T T Field emergence (%) (49.28) (21.32) (23.01) (30.14) (48.09) Mean S.Em.± CD (0.05) NS NS: Non significant T 1: 1/4 th yellow/orange T 2:1/2 yellow/orange T 3:3/4 th yellow/orange T 4: complete yellow/orange T 5: Control Figures in parentheses are arc sine transformed values

127 SVI SVII T1 T2 T3 T4 T5: Fig. 17. Influence of ring spot infection at fruit maturity stages on seedling vigour index-i and seedling vigour index-ii in papaya (Carica papaya L.) EC(µScm-1) T1 T2 T3 T4 T5 Fig. 18. Influence of ring spot infection at fruit maturity stages on electrical conductivity µscm -1 in papaya (Caricaa papaya L.) T 1: 1/4 th yellow/orangee T 2:1/2 yellow/orange T 3:3/4 th yellow/orangee T 4: complete yellow/orange T 5: Control