Amelioration of physiological disorders in pistachio nuts by organic manure and gypsum

Abstract

Pistachio is of high sensitivity to such physiological disorders as fruit abscission, endocarp lesion nut, blank, deformed, early split and non-split nuts. However, little research has been carried out on the physiological disorders in pistachio. In this study, the effects of organic manure, gypsum and boric acid treatments with their combination were studied on physiological disorders in ‘Kaleh-Ghoochi’ Pistachio. The treatments were done in autumn as soil application and physiological disorders as well as tree vegetative growth; in addition, biochemical traits including catalase (CAT), poly phenol oxidase (PPO), peroxidase (POD) and phenylalanine ammonilyase (PAL) enzymes activities, total phenol content and proline content were measured throughout the growth. Results showed that organic manure and gypsum treatments alone or in combination reduced the physiological disorders and improved split nut percent and vegetative growth in pistachio as compared to control; however, combination treatments were more effective than each treatment lonely in reducing physiological disorders and increasing split nuts and vegetative growth. Effective treatments also reduced CAT, PPO, POD and PAL enzymes activities and total phenol and proline contents in the nuts. Generally, an increase in physiological disorders was concomitant with an increase in the enzyme activities and total phenol and proline contents in pistachio. The boric acid has not been effective alone or in the combined treatment in this study.