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EFFECT OF SOME CHEMICAL THINNING COMPOUNDS ON FRUIT QUALITY OF TABLE OLIVES By DALIA MOHAMED HUSSEIN MOHAMED B.Sc. (Pomology),Fac.Agric.,Cairo Univ.,2006 THESIS Submitted In Partial of the Requirements of the Degree of MASTER OF SCIENCE In Agricultural Sciences (Pomology) Department of Pomology Faculty of Agriculture Cairo University EGYPT 2017 1 ABSTRACT This investigation was conducted during two successive seasons (2009-2010) on two olive cultivars (Manzanillo and Eggizi Shami) in a private orchard in the Alex. desert road. The aim of this study is to investigate the effect of some chemical thinning agents GA3 (100,150 and 200 p.p.m), NAA (100,150 and 200 p.p.m) and Urea (4,6,8 and 10%) sprayed at full bloom, five days after full bloom, ten days after full bloom and fifteen days after full bloom on initial fruit set (twenty one days after full bloom), final fruit set (forty five days after full bloom), sixty days after full bloom and at harvest date. The effect of these treatments on fruit characteristics (fruit length, diameter and weight) and oil content of Manzanillo and Eggizi Shami olive cvs. was also studied. The results showed that used chemical thinning agents reduced fruit set significantly and improved fruit quality and oil content compared with control (sprayed with water only). Urea spray was the most effective in reducing fruit set compared with GA3 and NAA. The highest concentration was more effective than the lower one in each chemical component. Fruiting of Manzanillo cv. was significantly lower than Eggizi Shami cv. GA3 of studied showed moderate effect in reducing fruit set (between Urea and NAA). The most effective date in reducing fruiting was at full bloom, while the lowest was at fifteen day after full bloom. It could be recommended that spraying with Urea or NAA at moderate concentration (4% and 150 p.p.m) was effective in reducing fruit set and improving fruit quality and oil content in both cultivars of study. 2 INTRODUCTION Olive (olea europaea L.) is a species of the oldest cultivated fruits since its fossilized leaves dating to around 37,000 years ago have been discovered on the Aegean island of santorini. The olive is belonged to the family oleaceae, which comprises of 22 genera and the genera Olea is one of them with 35 species (Heywood, 1978).The domesticated olives belong to the genus olea, species europaea, sub species sativa and number of the cultivated species is estimated more than 2500 cultivars. Olive cultivation plays an important role in the economy of many countries in the Mediterranean basin, it isn‟t only increase the land value where the soil is unsuitable for other crops, but also contributes to soil conservation and helps to overcome environmental problems (Dennis, 1977) Its fruit is of major agricultural importance in the Mediterranean region as the source of olive oil. The world production of olive, as shown in Table (1), was 20,344,342 tons. The major producer countries are Spain , Italy, Greece, Turkey, Morocco, Syria, Tunisia, Egypt, Algeria, Portugal and others, (FAO, 2013). Table1 : Countries and production with ton of olive trees. (FAO, 2013): Production Percent Country (Tons) (%) Spain 7,875,800 38.7 Italy 3,022,886 14.9 Greece 2,000,000 9.8 Turkey 1,676,000 8.2 Morocco 1,181,675 5.8 Syria 1,000,000 4.9 Tunisia 963,000 4.7 Egypt 510,000 2.5 Algeria 395,000 1.9 Portugal 350,900 1.7 Total 20,344,342 100 3 Table 2 : Egyptian Governorates area and production of olives (Ministry of Agriculture and Land Reclamation, 2013): New land Old land Total Fruiting Total Fruiting Prod. Prod. Governorate area area area area (Ton) (Ton) (Fed.) (Fed.) (Fed.) (Fed.) N. Sinai 43,468 24,864 56,839 - - - Noubaria 37,739 19,440 143,856 - - - Matruh 28,960 21,867 56,286 - - - S. Sinai 13,860 9,661 14,714 - - - Ismailia 13,523 7,283 48,111 6,048 5,623 37,146 Fayoum 10,671 10,671 49,268 4,220 4,219 19,479 Cairo 9,908 5,720 3,844 - - - (Others) 30,261 23,882 114,135 4,085 3,795 19,392 Total 188,390 123,388 487,053 14,353 13,637 76,017 The olive tree produces more flowers and sets more fruits than can be sustained by the available raw materials. This condition of heavy crop results in limb breakage; small fruit of less value, late maturity and poor quality; reduced vegetative growth; and ultimately depressed prices. The year following excessive production the return crop may be so depressed that harvest would not be economical. Use of (NAA) at(150 p.p.m) as a foliar spray effectively reduces crop size and helps to ensure larger individual fruit size the current year and return cropping the next year. Martin et al., (1980). The present study aimed to investigate: 1- The effect of some chemical thinning compounds (GA3 , NAA and Urea) used at full bloom, + five days after full bloom, + ten days after full bloom and fifteen days after full bloom on fruit set of Manzanillo and Eggizi Shami olive cvs. 4 2- The effect of previous chemical thinning compounds on fruit physical characteristics in both studied cvs. 3- The effect of chemical thinning compounds on fruit oil content of both studied cvs. REVIEW OF LITERATURE 1- Problems of olive production Olive (Olea europaea L.) shows alternate bearing, with unreliable cropping patterns and inconsistent fruit size and quality every year. Olive trees are prone to bear fruit in alternate cycles (Krueger et al., 2004; Lavee, 1996). The heavy crop loads of “on” seasons give rise to fruit of very poor quality while in “off” seasons, the increase in fruit size does not make up for the loss in yield (Krueger et al., 2004). The thinning of olive fruit in intensively irrigated orchards is a prerequisite for obtaining more suitable fruits heavy cropping years (on years). Olive growers are advised to do fruit thinning during “on” year crop to reduce the occurrence of alternate bearing ( Abu-Zahra and Al-Dmoor, 2013). In many countries, thinning NAA is used to minimize alternate bearing behavior in olives (Barone et al., 2013). Decreasing the crop load early in “on” seasons increases fruit quality in the year of application, and also increases the crop load in the subsequent season, thereby reducing the negative effects of yield alternation (Dag et al., 2009). Application of NAA at 100 - 150 p.p.m. at 15 days after full bloom (DAFB) has been used to chemically thin olives in various countries (Lavee, 2006). 2- Alternate bearing. Alternate bearing is a widespread phenomenon in many fruit trees and a major problem facing olive growers. Alternate bearing causes substantial fluctuation in income for olive farmers, as the heavy crop loads of “on” season give rise to very poor fruit quality, small fruit size in several oil cvs. (Dag et al., 2009) and table olive cultivars (Hartmann, 1952; Martin et al., 1980., Krueger et al., 2004., El-Sharony., 2012). 5 Fruit size is the limiting factor, as too small fruit do not qualify as table olives (Lavee, 2006), thus resulting in a significant loss of income, whereas the increase of fruit size in an “off‟‟ year does not make up for the loss in yield (Krueger et al., 2002). That said, not only does alternate bearing create challenges regarding operating and utilizing storage and processing facilities, but also with the planning of labour and other horticultural farming practices (Morselise and Goldschmidt, 1982). Olives are valued based on fruit size. Heavy crops have preponderance of small fruit that are expensive to pick and of little value. Further, olives are alternate bearing; light crops invariably follow heavy crops. Fruit thinning has been shown to reduce crop load, improving size of the remaining fruit and to minimize alternate bearing (Ferguson et al., 1994). Chemical thinning has certain advantages over hand or mechanical thinning: low thinning cost, greater size of olives, earlier maturation and better quality and decrease in biennial bearing (Loonnis, 2008). 3- Solving of alternate bearing. Excessive crops must be reduced early in the “on” season to overcome biennial bearing and to obtain adequate fruit quality. Fruit thinning can rectify or ameliorate an established alternate bearing cycle and is also a management technique used to increase fruit size (Link, 2000). Hartmann et al.,(1980) found that there are different cultural methods are commonly applied in the world in order to decrease the severity of alternation and improve the fruit quality in olive as well in many fruit species showing alternation. These methods can be summarized as breeding, fertilization, pruning, girdling, thinning, using of plant growth regulators and applying convenient harvest (Hartmann et al., 1980, Morselise and Goldscihmodt, 1982, Poli, 1987, El- Sharony, 2012). -Thinning. 4-Types of thinning. a. Hand thinning: Stino et al., (2010) studied the effects of manual thinning by removing 25 and 50% of the fruit set and foliar application of Pix (Mepiquat 6 chloride MC: N, N-dimethyl piperidiniurn chloride) at 500, 1000, 1500 and 2000 p.p.m (during the on‟ season) were assessed as tools to enhance fruiting of Picual and Manzanillo olive cultivars in the off season. Data clarified that manual thinning by removing 50% of the fruit set was the most effective treatment in increasing flowering density, sex ratio setting and yield. The attained effect was assumed to be due to reducing the number of fruits in the 'on' year which lead to increasing stored nutrients and assimilates in the on' year and or due to decreasing the inhibitory effect of seeds on floral bud induction and differentiation leading to better flowering and fruiting in the 'off year.

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