Influence of spraying Zinc Sulphat and Gibbralic Acid on yield and fruit properties of “Manzanillo” Olives

Abstract

This study was carried out during the two seasons 2013, 2014 on olive trees Manzanillo cv. The trees were 10 years old growing in sandy soil at a private orchard in Ismailia governorate, Egypt. This investigation was performed to study the effect of zinc sulphat and gibbralic acid (GA3) on olive trees Manzanillo cv. Zinc sulphat ( 0, 0.25 and 0.5%) was used as foliar application once time before flowering period and gibbralic acid ( 0 and 0.25 ppm) was sprayed once time after fruit set. At the end of the season, yield (kg/tree) and Fruit quality: average fruit size (volume), weight, shape index (length\ diameter) and pulp\pit ratio also fruit chemical characterizes: fruit oil and acidity percentage were recorded.  It is clear from data obtained that the response of Manzanillo olive trees to zinc sulphat spraying depended on the time of application as well as the concentration used, where full bloom is a suitable time for zinc sulphat to increase or improve physical fruit quality in terms of fruit weight (gm), volume (cm3) and pulp/pit. Meanwhile, zinc sulphat at 0.5% and gibbralic acid as a growth regulator at 10 ppm is recommended for increasing fruit weight and oil %, reduction in fruit drop, yield per tree.