Effect of proline and fruit bagging on the coloration of Aril and peel of “Wonderful” pomegranates

Abstract

Poor coloration of the arils and externally on the skin have been the main problems of pomegranates as well as skin cracking before harvest. This study was conducted during two consecutive seasons 2020 and 2021. Proline was sprayed alone or along with fruit bagging. The treatments included. The control (tap water spray, Proline at 0.25mM. proline at 0.25mM plus fruit bagging, proline at 0.5mM, proline at 0.5mM plus fruit bagging, proline at 1mM and finally proline at 1mM plus fruit bagging. The non-ionic surfactant top film was added to all used treatments at 0.05% (v/v). The treatments were applied by spraying three times to the run off after fruit set, at the initiation of rapid fruit elongation and at fruit maturity. The results indicated that there was an increase of anthocyanin in the skin whether alone or in the presence of bagging in a consistent manner. More the porline concentration, more the increase in skin color. Meanwhile, the greatest content of anthocyanin in the aril juice was obtained with proline at 1mM plus fruit bagging. In addition, proline at 0.5mM plus fruit bagging had a significant effect on aril's anthocyanin as compared with the control. Total soluble solids also increased significantly with the treatment of proline at 1mM plus fruit bagging. The same combination of treatments was also found with aril weight. More fruit characteristics were also discussed. In general, the use of proline spray three times has potential to enhance coloration of pomegranates especially in the presence of fruit bagging.