Physiological and biochemical responses of 'Divadona' peach on Rootpac 20 and Rootpac 40 under drought and heat stress adaptation and its recovery mechanisms.

Climate change-induced drought and heat stress pose significant challenges to global peach production, threatening agricultural sustainability and food security. This study, therefore, investigated the morphological, physiological and biochemical responses of the 'Divadona'peach cultivar grafted onto two different rootstocks (Rootpac 20 and Rootpac 40) under drought stress, heat shock, and their combination. We aimed to identify superior rootstock performances and understand stress tolerance mechanisms for improved cultivation strategies. Our findings revealed that combined stress induced the most severe impacts, with Rootpac 40 demonstrating superior stress tolerance. Under combined stresses, relative shoot diameter decreased less in Rootpac 40/'Divadona' (19.75%) compared to Rootpac 20/'Divadona', while relative shoot length showed similar patterns. Antioxidant enzyme activities increased significantly, with POD showing the highest elevation in Rootpac 40/'Divadona' compared to Rootpac 20/'Divadona. Stress markers exhibited substantial accumulation, with MDA content rising more in Rootpac 20/'Divadona' than in Rootpac 40/'Divadona'. Nutrient analysis showed that Rootpac 40/'Divadona' maintained higher levels of essential nutrients under stress, with nitrogen content declining less compared to Rootpac 20/'Divadona'. The study demonstrated that Rootpac 40/'Divadona' possesses superior stress tolerance mechanisms through better maintenance of growth parameters, enhanced antioxidant defense systems, and improved nutrient retention capacity. These findings provide valuable insights for fruit growing, enabling informed rootstock selection for peach cultivation in drought-prone regions, ultimately contributing to more resilient and sustainable fruit production systems under changing climatic conditions.