Effect of Repeated Foliar Application of Urea on Growth, Fruit Quantity and Quality of Pistacia vera Cv. “Kalleh-Ghuchi”

In this experiment, the effect of repeated foliar application of 0.5 percent urea at three different stages of fruit growth (including initiation of embryo growth, rapid growth of embryo and during flower bud abscission with two weeks interval) on growth and yield of pistachio was investigated. To this aim, 20 mature trees of Kalleh-ghuchi were selected from the Research Garden of Vali-e-Asr University of Rafsanjan, Iran in 2016. Growth characteristics such as shoot length, leaf number and the length of inter node were increased by increasing urea application events. Three times application of urea decreased bud abscission by 62%, also it resulted in a 65% increase in leaf nitrogen concentration compared to the control trees. Also L index of hull and cluster weight, nut weight and fruit moisture were increased by increasing urea application events, while fruit firmness and ounce were decreased by increase in urea application events. The presented data suggests that three times application of urea during the third stage of nut growth with two weeks-interval, can have some positive effects on qualitative and quantitative traits of fruit; furthermore, it can initiate alternate bearing by decreasing flower bud abscission during the “On” year.