EFFECT OF SPRAYING PICUAL AND KALAMATA OLIVE TREES WITH GA3 AND ZINC SULFATE ON PRODUCTIVITY AND FRUIT PROPERTIES

Abstract

Esraa Mohamed Mohamed Farahat: Effect of Spraying Picual and Kalamata Olive Trees With GA3 and ZnSO4 on Productivity and Fruit Properties. Unpublished M.Sc. Thesis, Department of Horticulture, Faculty of Agriculture, Ain Shams University, 2016. This study was conducted during 2011, 2012 and 2013 seasons in a private orchard located at Ismailia Governorate, Egypt. The trees were about eight years old grown in a sandy soil at five meters apart under drip irrigation system and received the ordinary horticultural practices. This work was divided into two separate experiments. The first amid to study the changes in some constituents in relation to fruit development stages. Results obtained provide that fruit development of both cultivars followed the double growth pattern (double Sigmoid curve) in which a great increase in fresh fruit weight occurred during the first stage, (about 10-12 weeks) after fruit set, followed by a very limited increment in fruit size for about (4-5 weeks) then a rapid increase in fresh fruit weight was followed. The change in fruit skin color shortly began during the early period of the third stage. The increment in fruit size prior to fruit coloration comes mainly from increased moisture content of the fruit. Oil begins to accumulate in the fruit and increases gradually through July, August and reaches the maximum as fruit become completely black. The second experiment was performed to study the effect of spraying Picual and Kalamata olive trees with the aqueous solution of GA3 at (0, 20 and 40 ppm) or ZnSO4 at (0.0, 0.5 and 1%) and their companions on trees productivity and fruit properties. Treatments were sprayed when fruits reached about two third of their commercial volume, the (beginning of final swelling stage). Data obtained revealed that for the Picual trees, the maximum increase in yield and flesh oil percentage resulted from spraying GA3 at 40 ppm alone. The highest values of fruit weight and volume and flesh /stone ratio were obtained in trees sprayed with GA3 at 40 ppm coupled with ZnSO4 at 1%. The highest fruit flesh oil percent (on fresh weight) found in fruits of trees received the 40 ppm GA3 plus ZnSO4 at 0.5%. The highest oil acid percentage was noticed in fruits from trees sprayed with ZnSO4 at 1%. While the oil of fruits from trees sprayed with GA3 at 20 ppm coupled with ZnSO4 either at 0.5 or 1 % showed the lowest peroxide values. Oil extracted from fruits of trees received the two high concentrations (GA3 at 40 ppm plus ZnSO4 at 1 %) showed the highest iodine value comparing with those of the other tested treatments.