Water Stress Effects on Phenolic and Antioxidant Capacity in ‘Pink Lady’ and ‘Jeromine’ Apples

Drought is a major abiotic stress limiting fruit yield and quality in apple ( Malus × domestica Borkh.), especially in semi-arid regions. This study evaluated the effects of drought stress on total phenolic content (TPC) and total antioxidant capacity (TAC) in two apple cultivars, ‘Pink Lady’ and ‘Jeromine’, grafted onto M9 rootstock and grown under the arid summer conditions of Karaman, Turkey, during the 2023–2024 seasons. Fruit samples were analyzed separately as flesh and peel + flesh tissues. Drought stress significantly increased TPC and TAC levels in both cultivars, with stronger responses in ‘Pink Lady’. The highest TPC (220.4 mg GAE/100 g FW) and TAC (159.1 µmol TE/100 g FW) were recorded in ‘Pink Lady’ peel + flesh tissue in 2024. Peel tissue contributed substantially to the overall antioxidant potential. These results indicate that cultivar selection plays a key role in maintaining fruit quality under drought conditions. ‘Pink Lady’ showed superior biochemical responses, suggesting its suitability for cultivation in drought-prone regions. Enhanced phenolic and antioxidant profiles may also improve the nutritional value and postharvest stability of the fruit.