Effect of Some Chemical Thinning Agents on Fruit Set of Manzanillo and Eggizi Shami Olive Cultivars

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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 ppm), NAA (100,150 and 200 ppm) and Urea (4,6,8 and 10%) which sprayed at full bloom, five days after full bloom, ten days after full bloom and fifteen days after full bloom on initial fruit set (21 days after full bloom), final fruit set (forty five days after full bloom) and at harvest date. The results showed that all chemical thinning agents reduced fruit set significantly 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 concentration in each chemical component. Fruiting at different time of estimation with Manzanillo cv. was significantly lower than Eggizi Shami cv. Gibberellic acid showed moderate effect in reducing fruit set (between Urea and NAA). The most effective date was 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 ppm) was effective in reducing fruit set in both cultivars of study.

El Said S. Hegazi
Ayman A. Hegazi
Dalia M. El Koly
Journal of Horticultural Science & Ornamental Plants