Effect of Spermine, Epibrassinolid and their interaction on inflorescence buds and fruits abscission of pistachio tree (Pistacia vera L.), “Ahmad–Aghai” cultivar

Several physiological problems such as abscission of inflorescence buds and fruit, incidence of blank, non–split and deformed nuts leads to diminish yield of pistachio trees. This research designed study the effects of epibrassinolid and spermine application on fruit disorders and abscission on Pistacia vera “Ahmad–Aghai” cultivar. Shoots, of pistachio trees sprayed with Epi–epibrassinolid and spermine, with three replicates. The hormonal treatments consisted of, 0.5 and 1 ppm Epi–Br and 100 and 200 ppm Spm and their combination. Some yield traits including inflorescence and fruit abscission were studied. Fruit abscission diminished significantly in all treatments in comparison with untreated hormonal trees. Epibrassinolid and spermine treatments decreased fruit blankness percentage and ethylene emission in compared with control. Simlutanouse application of epibrassinolid and spermine effectively raised split percentage in compared to each hormonal treatment alone. Chlorophyll content and carbohydrate content significantly increased by spermine 100 and 200 ppm, epibrassinolid 0.5 ppm and combination of spermine and epibrassinolid 0.5 in compared with the control. According to the results, it seems that spermine, epibrassinolid and combination of these hormones could significantly reduce fruit abscission and improve some of the physiological parameters in pistachio trees, probably through the antagonistic effects on ethylene production. Keyword: Ethylene emission, Fruit and bud abscission, fruit disorder, pistachio yield.