Effect of Some Growth Regulators, Nutrient Elements and Kaolin on Cracking and Fruit Quality of Pomegranate ‘Wonderful’ Cultivar

This study was carried out during two successive seasons 2016 and 2017 on six years old ‘Wonderful’ pomegranate trees (Punica granatum L.). Trees were grown on sandy loam soil conditions in a private orchard located at Burg El-Arab, Alexandria governorate, Egypt. The trees were spaced 4x5 m apart and irrigated by drip irrigation system and received similar cultural practices adapted in the orchard. The effect of some growth regulators, nutrient elements and kaolin on cracking and fruit quality of pomegranate ‘Wonderful’ cultivar was studied. The experiment was designed as randomized complete block design with five replicates. Each block contained 11 treatments (control, naphthalene acetic acid (NAA) at 25 and 50 mg/l, gibberellic acid (GA3) at 100 and 150 mg/l, boric acid at 0.1% and 0.3%, calcium chloride at 1% and 2% and kaolin at 4% and 6%). Results revealed that, boric acid at 0.3% gave the highest mean values of fruit set (%), number of fruits/tree, yield (kg/tree) and anthocyanin; while, naphthalene acetic acid at 50 mg/l recorded the maximum mean values of fruit weight, fruit diameter, volume and grain weight, and gave the minimum mean values of fruit drop and fruit cracking (%). On other hand, gibberellic acid (GA3) at 150 mg/l gave the maximum yield (kg/tree), in the second season and the minimum fruit cracking (%), whereas, calcium chloride at 2% gave the best results of TSS (%), acidity (%), and vitamin C, total and reducing sugars were higher than the control for all treatments. Finally, kaolin at 6% gave the lowest percentage of sunburn and the highest percentage of juice, as compared with the control and other treatments during both seasons.