Effects of Concentration and Time of Application of Gibberellic Acid on Reduction of Splitting percent of Pistachio Fruit

The present research was conducted in a commercial orchard of pistachio during 2006-2007 in Rafsanjan, Iran. Gibberellic acid (GA3) were applied at 0, 25, 50 and 75 mgL-1 and at three time of spray (the first of June, July and August) on “Ahmad-aghai” pistachio cultivar. Two branches of each tree was sprayed during two years of study. Spraying at June had least of early splitting. GA3 at 50 and 75 mgL-1 significantly reduced early splitting and cracking. Time of application had no significant effect on in dehiscent of pistachio nut. Percentage of indehiscent pistachio nut was increased by increasing the concentration of GA3. Spraying in August increased fat and protein content of kernel of pistachio nut. Treatments of GA3 had no significant effect on fat and protein content of kernel. GA3 was increased chlorophyll content of kernel of pistachio nut at 75 mgL-1.