Performance of "Marsh" Grapefruit and "Mexican" Lime Trees on Seven Rootstocks in Saudi Arabia.

Transcription

1 Performance of "Marsh" Grapefruit and "Mexican" Lime Trees on Seven Rootstocks in Saudi Arabia. Al-Obeed R.S., M. M. Harhash and M.M. Sourour Plant production Dept., College of Food & Agric. Sciences, King Saud Univ. ABSTRACT Two years field experiment was conducted on 6-year-old "Marsh" grapefruit (Citrus paradisi Macf.) and 'Mexican" lime (Citrus aurantifolia Swing.) trees during 2002/2003 and 20003/2004 growing seasons. The experimental trees were cultivated in sandy soil located at Deyrab, El-Riyadh governorate. The tested trees were budded on seven rootstocks namely: Cleopatra mandarin, Macrophylla, Volkamer lemon, Carrizo citrange, Troyer citrange, Shaub rough lemon and Estes rough lemon. Volkamer lemon rootstock promoted the fruiting potentiality of grapefruit trees (yield, fruit weight and fruit volume) followed by Shaub and Estes rough lemon rootstocks in both seasons. Lime trees on Macrophylla and Carrizo citrange rootstocks were the most productive in both seasons. The fruit characteristics, i.e. fruit weight, volume, length, diameter, shape, peel thickness, peel weight, juice percentage, TSS, acidity, TSS/acidity ratio and V.C were nearly higher in fruit collected from grapefruit and lime trees on Macrophylla and Carrizo Citrange rootstocks, respectively. INTRODUCTION Citrus acreage in the kingdom of Saudi Arabia reached ha in The total production of this area amounted to about ton of fruits (Agric.Stat.Year Book, 2004).This means that the average yield of citrus trees in the kingdom is 13.6 ton per hectare which is far below the average one of most citrus growing area in the world which reaches about 25 tons or more per hectare (FAO, 2004).Riyadh region comprises about 20% of total citrus production area of the kingdom. The total local production of citrus fruits represents a small percentage of total consumption. Therefore, the development of citrus crop needs to increase its productivity and use capacity. The rootstock scion relationship is a major factor in citrus tree establishment and productivity throughout the different environmental conditions. In the meantime, the ultimate objectives of citrus growers aim at optimization and regulation of output throughout the productive life of citrus trees. To achieve this, it is necessary to obtain information with respect to the effect of rootstocks on yield and fruit quality under the conditions prevailing in certain locality. Rootstocks have had a substantial role in the development of the citrus industry in the world. The effect of rootstocks on citrus fruit production Vol. 10 (1), 2005 ١٦٥

2 and fruit quality has been intensively studied in many citrus producing areas (Continella et al.,1988; Economides and Gregoriou, 1993; Fallahi and Rodney, 1992; Fallahi et al., 1989; Gardner and Horanic, 1961 and 1967; Grisoni et al., 1989; Monteverde et al., 1988; Roase and Maxwell, 1979, Rouse et al., 1989; Wheaton et al., 1991; Zekri, 1996, 1997, 1999, 2000a and 2000b; Al-Jaleel and Zekri, 2003).These studies have revealed different results and inconsistent conclusions, which were attributed to several factors including climatic conditions and soil characteristics. Therefore, it is unwise to adopt rootstock recommendations from one part of the world to another without a locally thorough evaluation. So, the present investigation was carried out during 2003 and 2004 seasons to evaluate the performance of "Marsh" grapefruit and "Mexican" lime trees on seven rootstocks in Saudi Arabia. MATERIALS AND METHODS The present investigation has been carried out during 2003 and 2004 growing seasons in order to study the performance of "Marsh" grapefruit (Citrus paradisi Macf.) and 'Mexican" lime (Citrus aurantifolia Swing.) trees budded on seven rootstocks namely: Cleopatra mandarin (Citrus reshi Hort. ex. Tan.), Macrophylla (Citrus macrophylla Wester), Volkamer lemon (Citrus volkameriana Ten ), Carrizo citrange & Troyer citrange (Citrus sinensis Osbeck Poncirus trifoliata. Raf.),Shaub and Estes rough lemons (Citrus jambhiri Lush.). The trees, six-year old, were grown in sandy loam soil at 5m apart in the Agricultural Experimental and Research Station (Deyrab) of the Faculty of Food Sciences and Agriculture-King Saud University, Riyadh. Representative soil samples under the experimental trees were collected, physically and chemically analyzed prior to initiating the experiment according to the procedure outlined by Wilde et al., 1985 (Table 1). Table (1): Physical and chemical analysis of the soil samples collected from the experimental orchard. Depth Sand cilt Clay Om Ca Ec Anions (meq/l) Cations (meq/l) (cm) (%) (%) (%) (%) Co3 % dsm - 1 HCO 3 - Cl - SO 4 - Ca ++ Mg ++ Na + K Vol. 10 (1), 2005 ١٦٦

3 The bud wood source and budded trees were free of viruses and viroids. Trees of the seven rootstock treatments were established in a randomized complete block design with five replicates of each variety ("Marsh" grapefruit and "Mexican" lime). The tested trees received the same agro-technical practices adopted in this district. Each tree was subjected to two drip irrigation emitters (4L h -1 ) located 50cm from opposite sides of the tree. At harvest time (first week of January and September for grapefruit and lime, respectively of each season), the mature fruits were harvested at the yellow orange skin color stage and the yield per tree was expressed by weight of fruits/tree (kg). Random samples of 20 fruits were harvested from each tested tree for fruit quality determinations. In each fruit sample, fruit weight,volume, length (L), diameter (D), fruit shape (L/D) and rind weight were measured. The rind thickness was measured at the equator (using digital caliper). Juice was extracted with a motor-driven hand reamer (Santos, No. 11). The juice content as a percentage of fruit weight was recorded. The percentage of total soluble solids (TSS) was determined in fruit juice using BRX-242 digital refractometer. Juice acidity percentage (estimated as citric acid equivalent) was determined by titration with NaOH and phenolphthalein indicator and TSS/acid ratios were also determined. Ascorbic Acid (Vitamin C) was determined by titration with 2, 6- dichlorophenolendophenol blue dye (A.O.A.C. 1986).The same trees were tested throughout both experimental seasons and the experiment was arranged in a complete randomized design. Each treatment (rootstock) was replicated five times with an individual tree for each replicate. Appropriate analysis of variance was performed to examine rootstock effects on yield and fruit quality characteristics on the obtained results of both experimental seasons. Comparisons among means of different treatments were carried out by the least significant difference LS.D. test at p= 0.05 level as described by Steel and Torrie (1980). Computation was performed using SAS computer program package (1989). RESULTS AND DISCUSSION The data concerning the yield and fruit quality parameters of grapefruit and lime trees grown on the different rootstocks in 2003 and 2004 seasons are listed in Tables (2 to 6). 1- Tree yield : The data presented in Table (2) clearly showed that grapefruit trees on Volkamer lemon rootstock yielded significantly higher fruit yield Vol. 10 (1), 2005 ١٦٧

4 compared with the remained ones in both seasons. The second rank was Shaub rough lemon and the least fruit yield was from the Troyer citrange rootstock in both experimental seasons. In addition, the tested rootstocks induced significant differences in fruit yield in both experimental seasons, except between Carrizo and Troyer citrange, with Cleopatra mandarin joining them in the second season. Regarding the lime yield, the present results revealed that in both seasons, Macrophylla was the most productive rootstock. The effect of the tested rootstocks was statistically significant in both 2003 and 2004 seasons. Carrizo Citrange yield was the second in rank and the least fruit yield was harvested from Troyer Citrange rootstock in both experimental seasons. These findings are in agreement with results of several studies conducted in different citrus growing regions where cumulatyields were higher on trees budded on Volkamer lemon than those budded on Swingle Citromelo and Cleopatra Mandarin (Castle et al., 1993: Fallahi et al. 1989: Monteverde et al. 1988; Wutscher and Shull, 1976: Zekri,2000b and Al- Jaleel and Zekri, 2003). However, in other studies, no significant differences in cumulative yields were found among rootstocks including Cleopatra mandarin, Sour orange, Carrizo citrange, Volkamer lemon, Rough lemon and Macrophylla (Fallahi et al., 1991 and Hearn, 1989). All these findings indicated the inconsistency in yield differences as affected by rootstocks, which could be attributed to differences in scion cultivars, tree age, climatic conditions and soil characteristics. Table (2): Effect of different rootstocks on the yield of "Marsh" grapefruit and "Mexican" lime in 2003 and 2004 seasons. Rootstock Yield (kg) "Marsh" grapefruit "Mexican" lime Cleopatra mandarin Macrophylla Volkamer lemon Carrizo citrange Troyer citrange Shaub rough lemon Estes rough lemon L.S.D. at 5% Vol. 10 (1), 2005 ١٦٨

5 2- quality: 2.1. Physical fruit characteristics: Tables ( 3 and 4) show the average fruit weight, fruit volume, fruit length, fruit diameter, fruit shape as well as both peel thickness and weight of grapefruit and lime fruits as affected by the different rootstocks in the two seasons. The present results revealed that in both seasons, there were differences between rootstocks due to their effects on the physical parameters of fruit quality. Data showed that the highest fruit weight, volume, length, diameter and peel weight were produced by grapefruit trees budded on Macrophylla in both seasons. Differences were statistically significant between Macrophylla rootstock and the remained ones, except for fruit volume obtained from Estes rough lemon rootstock in 2003 season. Regarding the fruit peel thickness, Shaub rough lemon rootstock in both seasons yielded significantly the highest peel thickness, except for fruits from trees on Carrizo citrange rootstock in the second season. Both extremes in peel thickness are not desirable. with thick peel are usually low in juice, while those with thin peel are prone to splitting and are sensitive to postharvest problems that can occur during shipping and storage. The obtained data revealed that concerning the main lime fruit characteristics i.e. fruit weight, fruit volume, fruit length, fruit diameter and fruit shape followed nearly similar trends as affected by rootstocks. Thus, it is obvious that the highest mentioned parameters were found in lime fruits collected from trees on Carrizo rootstocks in both experimental seasons. Carrizo rootstock significantly gave higher values for the considered parameters in both seasons. Worthwhile a slight increment in fruit length on Carrizo rootstock was observed over the remained rootstocks with only a significant difference with Estes rough lemon rootstock in the second season. It is worthy to mention that the fruit shape differences were statistically significant between Carrizo citrange rootstock and the remained ones in the first season and between Cleopatra mandarin and Macrophylla rootstocks in the second season. Concerning lime fruit peel thickness and weight, data of both seasons revealed that the uppermost values resulted always from trees on Shaub rough lemon rootstock. On the other hand, the least values resulted always from Cleopatra mandarin rootstock. Significant differences were detected only in the first season in peel thickness between Shaub rough lemon on one hand and both Cleopatra mandarin and Troyer citrange rootstocks on Vol. 10 (1), 2005 ١٦٩

6 the other hand. No significant differences were observed in peel weight among all the tested rootstocks in Meanwhile, peel weight was statistically significant in Shaub rough lemon rootstock compared with Cleopatra mandarin, Macrophylla, Volkamer lemon and Troyer citrange rootstocks in 2004 season. Results of the present study are in harmony with those of Al-Jaleel and Zekri (2003); Georgiou (2000) and Forner-Giner et al., (2003). Table (3): Effect of different rootstocks on some fruit physical characters of "Marsh" grapefruit in 2003 and 2004 seasons. Rootstock weight g volume cm 3 length cm diameter cm shape Peel thickness mm Peel weight g Cleopatra mandarin 2003 season Macrophylla Volkamer lemon Carrizo citrange Troyer citrange Shaub rough lemon Estes rough lemon L.S.D. at 5% season Cleopatra mandarin Macrophylla Volkamer lemon Carrizo citrange Troyer citrange Shaub rough lemon Estes rough lemon L.S.D. at 5% Vol. 10 (1), 2005 ١٧٠

7 Table (4): Effect of different rootstocks on some fruit physical characters of "Mexican" lime in 2003 and 2004 seasons. Rootstock weight g volume cm 3 length cm diamete r cm shape Peel thicknes s mm Peel weight g 2003 season Cleopatra mandarin Macrophylla Volkamer lemon Carrizo citrange Troyer citrange Shaub rough lemon Estes rough lemon L.S.D. at 5% season Cleopatra mandarin Macrophylla Volkamer lemon Carrizo citrange Troyer citrange Shaub rough lemon Estes rough lemon L.S.D. at 5% Chemical fruit characteristics: Influence of different rootstocks on some chemical fruit properties of grapefruit and limes trees in 2003 and 2004 seasons is shown in Tables (5 and6) Juice content : Generally, grapefruit juice content was relatively high (around 41%). The juicer the fruit, the better is its acceptance not only for the juice market but also as a fresh fruit. Like other fruit quality variables, juice content was affected by rootstocks and varied through the seasons. The obtained data revealed that the fruit juice content followed nearly similar response with the tested rootstocks in both experimental seasons. s from trees on Cleopatra mandarin, Troyer citrange, Shaub rough lemon and Macrophylla rootstocks gave higher values for the considered parameter in both seasons. The uppermost values resulted always from Cleopatra Mandarin, descendingly followed by Troyer Citrange, Shaub and Macrophylla then the remained rootstocks. On the other hand, the least values resulted in both seasons from fruits on Volkamer Lemon rootstock. Worthwhile, differences among the tested rootstocks were statistically significant in 2003 season, except between Cleopatra Mandarin and Troyer Citrange rootstocks. This was true, except between Cleopatra Mandarin on one hand and both Vol. 10 (1), 2005 ١٧١

8 Troyer Citrange and Shaub rough lemon rootstocks on the other hand in The obtained results are in accordance with those found by Castle and Phillips (1980) and Fallahi et al. (1989) working on "Marsh" and "Redblush" grapefruit varieties, respectively. Also, the present results are in harmony with those of Wutscher and Bistline (1988) who mentioned that "Hamlin" orange fruit from trees on rough lemon and Volkamer lemon rootstocks had the lowest juice content. Similarly, the juice content was relatively high (around 48.5 %) in lime fruit. It is obvious that the tested rootstocks markedly affected the lime juice content in both experimental seasons. Data of the first season clarify that Macrophylla rootstock was pioneer and always surpassed other rootstocks in the juice percentage. However, insignificant differences were found between Macrophylla rootstock and the remained ones, except Carrizo rootstock. Analogical pattern of response was observed in the second season. Worthwhile, significant differences were found between Macrophylla rootstock on one hand and each of Cleopatra mandarin, Troyer citrange, Shaub and Estes rough lemon on the other hand. Meanwhile, not all studies demonstrated rootstock influence on juice content. For example, no significant differences in juice content of "Persian" lime', "Comune" clementine, "'Fairchild" mandarin, 'Orlando' tangelo and grapefruit were found from trees grown on all the studied rootstocks Al-Jaleel et al. (2005); Colburn et al., (1963); Continella et al., (1988); Fallahi and Rodney, (1992); Wutscher and Shull, (1976) and Wutscher et al. (1975) Total soluble solids: The flavor and palatability of citrus fruit is a function of relative levels of TSS, acids and the presence or absence of various aromatic or bitter juice constituents (Davies and Albrigo, 1994). Although fruit quality standards, which determine minimum levels of acceptability, has not been established in Saudi Arabia, soluble solids concentration in the juice has not been completely ignored as an important parameter for fresh fruit. Data of both experimental seasons clearly showed that TSS of grapefruit juice was noticeably affected by the different rootstocks. It is obvious that Cleopatra mandarin, Troyer and Carrizo citrange rootstocks significantly encouraged and promoted the TSS percentages over the remained rootstocks in both seasons. Also, it is worthy to mention that the lowest values in this respect came from Volkamer lemon in 2003 and 2004 seasons. Vol. 10 (1), 2005 ١٧٢

9 Similarly, the present investigation revealed that rootstocks were found to affect markedly TSS in lime juice. Results revealed that juice of fruits from trees on Macrophylla, Estes rough lemon and Troyer citrange rootstocks always yielded the highest TSS percentages in both seasons, meanwhile the lowest values with Cleopatra mandarin. Significant differences were detected between the three pioneers mentioned rootstocks and the remained ones in both experimental seasons, except Volkamer lime in the second season. The obtained findings are in line with those reported by Economides and Gregoriou (1993); Gregoriou and Gregoriou (1998) and Zekri and Al- Jaleel (2000).The results on soluble solids of all these studies are consistent showing poorer internal fruit quality for trees grown on relatively vigorous rootstocks such as Estes rough lemon and Volkamer lime compared with trees grown on less vigorous rootstocks such as Swingle citrumelo and Sour orange Acid content: Total acidity percentages of citrus juices can be considered as limiting factors in overall juice quality parameters and in determining time of harvest in several citrus producing regions. Table (5): Effect of different rootstocks on some fruit chemical characters of "Marsh" grapefruit in 2003 and 2004 seasons. Rootstock Juice % TSS % Acidity % TSS/ Acidity V.C mg/100 ml juice 2003 season Cleopatra mandarin Macrophylla Volkamer lemon Carrizo citrange Troyer citrange Shaub rough lemon Estes rough lemon L.S.D. at 5% season Cleopatra mandarin Macrophylla Volkamer lemon Carrizo citrange Troyer citrange Shaub rough lemon Estes rough lemon L.S.D. at 5% Vol. 10 (1), 2005 ١٧٣

10 Table (6): Effect of different rootstocks on some fruit chemical characters of "Mexican" lime in 2003 and 2004 seasons. Rootstock Juice % TSS % Acidity % TSS/ Acidity 2003 season Cleopatra mandarin Macrophylla Volkamer lemon Carrizo citrange Troyer citrange Shaub rough lemon Estes rough lemon L.S.D. at 5% season Cleopatra mandarin Macrophylla Volkamer lemon Carrizo citrange Troyer citrange Shaub rough lemon Estes rough lemon L.S.D. at 5% V.C mg/ 100 ml juice Results of the present study demonstrated that the acidity percentages in the juice of grapefruit differed among the tested rootstocks. In both seasons, the obtained data clarify highest acid content in fruits from trees on Troyer citrange over the remained rootstocks. Differences due to the previous rootstock in levels of acidity were significant in both seasons. However, the least values always resulted from fruits of trees on Cleopatra mandarin in 2003 and These results confirmed those of Fallahi et al., (1991); Fallahi and Rodney (1992) working on 'Orlando' tangelo and 'Fairchild' mandarin, respectively and Al-Jaleel and Zekri (2003) on 'Parent Washington Navel' trees. Concerning lime trees, rootstocks seem to affect greatly the fruit acid content in both seasons. It is clear that the highest acid content always resulted in fruits from trees on Shaub rootstocks. On the other hand, Cleopatra mandarin rootstock yielded the lowest values in this respect. Significant differences were found between Shaub and all the remained rootstocks in the second season. These findings are in agreement with those reported by Al-Jaleel and Zekri (2003); Zekri and Al-Jaleel (2004) and Al-Jaleel et al., (2005) working on 'Allen Eureka' lemon. Although internal fruit quality including acid content can be affected by the scion cultivar, tree age and other factors, the Vol. 10 (1), 2005 ١٧٤

11 results on acid content from most of these studies are consistent showing relatively lower acid content for trees grown on vigorous lemon rootstocks Total soluble solids: acid ratio: Total soluble solids/ acid ratio can be considered as an alternative parameter of fruit quality component and play important roles in fruit juice industry. The present investigation revealed that Cleopatra mandarin rootstock induced the highly TSS/acid ratio in grapefruit over the tested rootstocks in both seasons. In this respect, the mentioned rootstock surpassed significantly all the remained rootstocks in both experimental seasons. In the meantime, data of the present trial indicated that the TSS/acid ratio in lime fruit was noticeably affected by the different tested rootstocks. However, no consistent trend could be traced in this respect. These findings partially agreed with those reported by Castle and Phillips, 1980 on 'Marsh' grapefruit and Georgiou (2000) on 'Nova' mandarin Vitamin C: Data concerning the effect of various rootstocks on the ascorbic acid content of fruit juice of grapefruit and lime trees revealed that the consider parameter was not greatly affected in both seasons. However, Carrizo rootstock induced significantly highest V.C content in grapefruit juice as compared with both Macrophylla and Troyer citrange only in the first season. Likewise, V.C content in lime fruit juice was not noticeably affected by the different tested rootstocks. However, it is worthyto note that Shaub rough lemon rootstock yielded significantly the highest V.C in lime juice in the first season only when compared with Macrophylla and Volkamer lemon rootstocks. In the second season, results revealed that juice of fruits from trees on Cleopatra mandarin and Carrizo rootstocks yielded significantly the highest V.C content. Conclusion: yield and quality must be considered together when making rootstock choices, because of the critical role of fruit quality in the commercial profitability of citrus destined for fresh consumption. Consequently rootstocks that result in improved grapefruit and lime fruit quality will be often chosen even if their yield performance is not the highest. Given that our experiment was conducted with a narrow range of Vol. 10 (1), 2005 ١٧٥

12 rootstocks (all of them already in use commercially) and that edaphic and climatic conditions, except temperature were near optimal for both tested cultivars (Hodgson, 1967) it may be possible that experiments with more diverse rootstocks under less-ideal conditions can be concluded in a shorter period. In our experiment "Macrophylla" and "Carrizo Citrange", on balance, could be considered the best commercial rootstocks choice for "Marsh" grapefruit and "Mexican" lime grown under similar conditions. REFERENCES Agriculture Statistical Year Book Agricultural Research and Development Affairs. Department of Studies Planning and Statistics.17 th Issue. Saudi Arabia Kingdom. Al-Jaleel, A. and M. Zekri Yield and fruit quality of "Olindo Valencia" trees grown on nine rootstocks in Saudi Arabia. Proc. Fla. State Hort. Soc. 115: Al-Jaleel, A. and M. Zekri Effects of rootstocks on yield and fruit quality of "Parent Washington Navel" trees. Proc. Fla. State Hort. Soc. 116: Al-Jaleel, A., M. Zekri and Y. Hammam Yield, fruit quality, and tree health of 'Allen Eureka' lemon on seven rootstocks in Saudi Arabia. Sc. Hort.,105: A.O.A.C Association of Official Agricultural Chemists. Official and Tentative Methods of analysis. 13 th ed. Association of Official Agricultural Chemists, Washington, D.C., USA. Castle, W.S.and R.L.Phillips Performance of Marsh grapefruit and Valencia orange trees on 18 rootstocks in a closely spaced planting. J. Amer. Soc. Hort. Sc. 105: Castle, W.S., D. P. H. Tucker, A. H. Krezdorn, and C.O. Youtsey Rootstocks for Florida citrus. Fla. Coop. Ext. Serv. Bull. SP 42. Colburn, B., F.E. Gardner and G.E. Horanic A rootstock trial for Tahiti limes in Dade County, Florida. Proc. Fla. State Hort. Soc. 76: Continella, G., C.Germana, G. La Rosa and E. Tribulato Performance and physiological parameters of Comune" Clementine influenced by four rootstocks. Citrus Congr. Proc. Sixth Inter. pp Davies, F.S. and L.G. Albrigo Citrus. CAB international, Wallingford. Vol. 10 (1), 2005 ١٧٦

13 Economides, C.V. and C. Gregoriou Growth, yield and fruit of nucellar frost "Marsh" grapefruit on fifteen rootstocks in Cyprus. J. Amer. Soc. Hort. Sc. 118: Fallahi, E.and D.R. Rodney Tree size, yield, fruit quality and leaf mineral nutrient concentration of "Fairchild" mandarin on six rootstocks. J. Amer. Soc. Hort. Sc.117: Fallahi, E., J.W. Moon, J and D.R. Rodney Yield and fruit quality of "Redblush" grapefruit on twelve rootstocks. J. Amer. Soc. Hort. Sc.114: Fallahi, E, Z. Mousavi and D.R.Rodney Performance of "Orlando" trees on ten rootstocks in Arizona. J. Amer. Soc. Hort. Sc.116:2-5. FAO Food and Agriculture Organization. FAOSTAT data. http//faostat.fao.org/faostat/collections. Forner-Giner, M.A., A. Alcaide, E. Primo-Millo and J.B.Forner Performance of "Navelina" orange on 14 rootstocks in Northern Valencia (Spain).Sci. Hort.98: Gardner, F. E. and G. E. Horanic A comparative evaluation of rootstocks for Valencia and Parson Brown oranges on Lakeland fine sand. Proc. Fla. State Hort. Soc. 74: Gardner, F. E. and G. E. Horanic Poncirus trifoliate and some of its hybrids as rootstocks for Valencia sweet orange. Proc. Fla. State Hort. Soc. 53: Georgiou, A Performance of "Nova" mandarin on eleven rootstocks in Cyprus. Sci. Hort. 84: Georgiou, A., and Georgiou C Yield and fruit quality of 'Shamoutia' orange on 14 rootstocks in Cyprus. Sci. Hort. 1307:1-10. Grisoni, M., P. Cabeu and Aubert Resultants de douze années d'un essai de comprtement de cinq porte-greffe en association avec quatre cultivars d'agrumes à l'ile de la Reunion. s 44: Hearn, C.J Yield and fruit quality of "Ambersweet" orange hybrid on different rootstocks.. Proc. Fla. State Hort. Soc. 102: Hodgson, R.W Horticultural varieties of citrus. In: Reuther, W., H.J. Bachelor, L.D. (Eds.). The Citrus Industry, vol.1. University of California, Berkley, pp Montverde, E.E., F.J. Reyes, G. Laborem and J.R.Ruiz Citrus rootstocks in Venezuela: Behavior of Valencia orange on ten rootstocks. Proc. Sixth Inter. Citrus Congr Roase, R.E. and N. P. Maxwell Performance of mature nucellar "Red Blush" grapefruit on 22 rootstocks in Texas. J. Amer. Soc. Hort. Sci. 104: Vol. 10 (1), 2005 ١٧٧

14 Rouse, M.L., D.A. Cole, D. Atkin and R.S. Kupper Yield and tree size of four citrus cultivars on 21 rootstocks in California. J. Amer. Soc. Hort. Sc.114: J. Amer. Soc. Hort. Sc.114: SAS Institute, SAS/ STAT User's Guide, Version 6, 4 th ed., vol.1 Cary, NC. Steel, R.G. and J.H. Torrie Principles and procedures of statistics. 2 nd ed., McGraw-Hill Book Comp. New York, USA, pp.328. Wheaton, T.A., W.S. Castle, J.D. Whitney and D.P.H.Tucker Performance of citrus scion cultivars and rootstocks in a high-density planting. Hortscience 26: Wilde, S.A., R.B. Cory, J.G. Lyer and G.K. Voigte Soil and Plant analysis for Tree culture. Oxford and IBH publishing Co. New Delhi. pp Wutscher, H.K. and A.V. Shull Performance of Orlando tangelo on 16 rootstocks. J. Amer. Soc. Hort. Sci. 101 (1): Wutscher, H.K. and F.W. Bistline Performance of "Hamlin" orange on 30 citrus rootstocks in southern Florida. J. Amer. Soc. Hort. Sc.113: Wutscher, H.K., N.P. Maxell and A.V. Shull Performance of nucellar grapefruit, citrus paradise Macf. on 13 rootstocks in south Texas. J. Amer. Soc. Hort. Sc.100: Zekri, M Leaf mineral concentration, growth, yield, fruit quality and economics of "Ambersweet" orange trees on two rootstocks. Proc. Fla. State Hort. Soc. 109: Zekri, M Performance of "Ambersweet", a new citrus hybrid cultivar, on two rootstocks in Florida. s 52: Zekri, M Performance of "Valencia" orange trees in a high-density planting. Proc. Inter.American Soc. for Tropical Hort. 43: Zekri, M. 2000a. Citrus rootstocks affect scion nutrition, fruit quality, growth, yield and economical return. s 55: Zekri, M. 2000b. Evaluation of orange trees budded on several rootstocks and planted at high-density on Flatwoods soil. Proc. Fla. State Hort. Soc.113: Zekri, M. and A. Al-Jaleel The citrus industry in Saudi Arabia. The Citrus Industry Mag. 81: Zekri, M. and A. Al-Jaleel Evaluation of rootstocks for Valencia and Navel orange trees in Saudi Arabia. s 59: Vol. 10 (1), 2005 ١٧٨

15 الملخص العربى سلوك ا شجار الجريب فروت "مارش" و "الليمون المكسيكى" المطعومة على سبع من ا صول الموالح فى المملكة العربية السعودية راشد سلطان العبيد محمد محمد حرحش محمد محمود سرور قسم الا نتاج النباتى-كلية علوم الا غذية والزراعة جامعة الملك سعود ا جريت هذه الدراسة خلال موسمى ٢٠٠٤/٢٠٠٣ على اشجار جريب فروت صنف "مارش" وا شجار ليمون صنف " مكسيكى" مثمرة عمر ٦ سنوات منزرعة فى ا رض لومية رملية بمنطقة "ديراب" بالرياض.نوعى الا شجار كانت مطعومةعلى سبعة من ا صول الموالح هى يوسفى كليوباترا, ماكروفيلا, فولكاماريانا, كاريزو سيترانج, تروير سيترانج, والليمون المخرفش (ا يستس و شوب). ا ظهرت الدراسة ا ن ا شجار الجريب فروت المطعومة على ا صل "فولكاماريانا" ا كثر ا نتاجية من حيث المحصول ووزن الثمار وحجمها يليها المطعومة على اصل الليمون المخرفش "شوب" فى كلا الموسمين. كما كانت ا شجار الليمون فى كلا الموسمين المطعومة على ا صلى "الميكروفيلا" و"كاريزو سيترانج" الا على فى ا نتاجية المحصول. وا ما بالنسبة لخصاي ص جودة الثمار من حيث وزن الثمرة حجم الثمرة طول الثمرة قطر الثمرة شكل الثمرة و سمك القشرة وزن القشرة النسبة المي وية لحجم العصير النسبة المي وية للمواد الصلبة الذاي بة الكلية النسبة المي وية للحموضة نسبة المواد الصلبة الذاي بة الكلية/الحموضة وفيتامين ج فكانت نسبي ا الا على فى ثمار كل من ا شجار الجريب فروت المطعومة على ا صل الماكروفيلا وا شجار الليمون المطعومة على ا صل كاريزو سيترانج. Vol. 10 (1), 2005 ١٧٩