Positive effects of foliar application of Ca, B and GA3 on the qualitative and quantitative traits of pomegranate (Punica granatum L.) cv. ‘Malase-Torshe-Saveh’

Abstract

Fruit cracking and sunburn are two main disorders that adversely affect pomegranate production in Iran. Proper horticultural practices during growing season can highly affect the fruit quality. In the present study, an experiment was conducted to assess the individual and combined effects of Calcium (Ca) (0, 0.75% and 1.5%), Boron (B) (0 and 3000 ppm) and gibberellic acid (GA3) (0, 75 and 150 ppm) spraying on the fruit of pomegranate cv. ‘Malase-Torshe-Saveh’. The treatments were repeated three times during growing season. A factorial experiment was conducted based on the completely randomized block design with 18 treatments and 3 replicates and data was analyzed with SAS and JMP software. Results indicate that most of the qualitative and quantitative traits were affected by foliar spraying of these substances. The control plants resulted in the inferior fruits attributes and the highest fruit cracking and sunburn was recorded from untreated plants. Although all of the individual treatments, increased physical attributes of pomegranate fruit, however, GA3 was the most effective and resulted in the highest fruit length and diameter, fruit and 100 arils weight as well as tree yield. We observed that B application not only improved different fruit qualitative traits including size, weight and yield, but also reduced fruit cracking mainly through improving water content of fruit peel. Ca treatment was the most effective for improving fruit qualitative characteristics including TSS and reducing the cracking disorder. Altogether, our results indicated that combinatorial spraying of Ca, B and GA3 is more efficient than their individual treatment and resulted in the highest fruit yield and quality as well as the lowest cracking and sunburn disorders, which propose there are synergistic effects between these compounds. Therefore, simultaneous spraying of these three substances is suggested in orchard management for improvement the qualitative and quantitative characteristics of pomegranate cv. ‘Malase-Torshe-Saveh’.