Preharvest Gibberellin Treatment Modulates Postharvest Quality and Metabolism in CCP76 Cashew Peduncle

This study aimed to evaluate how preharvest treatment with different GA₃ concentrations (0, 90, 180, 270, and 360 ppm) at the initial stage of CCP76 cashew development affects postharvest quality and further investigate the influence on metabolism through histology and metabolomic profile of ripe peduncles. All GA₃ treatments increased total and peduncle mass and firmness; but doses from 180 ppm, reduced total vitamin C, ascorbic acid (AsA) and sugar contents, thus increasing the dehydroascorbic acid (DHA)/AsA ratio. The microstructure of the control and GA₃-treated ripe CCP76 cashew peduncle was visually uniform with a waxy peel intimately adhered to the parenchyma cells. The metabolomic analysis of cashew peduncles identified 47 primary metabolites, and the variable importance in projection (VIP) analysis highlighted 15 key metabolites, among which the most influential were xylulose, erythronic acid, arabinonic acid and arabinose. Based on the results, we proposed that GA₃ influenced cashew peduncle metabolism through changes in cell energy-related processes and the increase in DHA/AsA ratio, together with the increase in erythronic acid would play a role in antioxidant defense responses. It is important to note that GA₃ at 90 ppm improved CCP76 cashew mass and firmness without significant impairing other quality-related characteristics.