Effect of drought stress on physiological, biochemical and antioxidant activity of wheat genotypes at booting stage

Drought is a major abiotic stress affecting wheat (Triticum aestivum L.) cultivation, particularly in arid and semi-arid regions. This study was conducted on three wheat genotypes PBW644, WH1080 and PBW175 under controlled conditions at the Division of Plant Physiology, Sher-e-Kashmir University of Agricultural Sciences and Technology, Jammu. The experiment involved withholding irrigation for 10 days during the booting stage, with sampling carried out at the onset of wilting and leaf rolling symptoms. The objective was to investigate drought-induced changes in physiological, biochemical and antioxidant responses and their impact on yield-related traits. PBW644 exhibited superior drought tolerance, maintaining higher chlorophyll stability, water use efficiency and osmotic adjustment (proline and sugar accumulation). Antioxidant activity (SOD and CAT) was significantly upregulated, with PBW644 showing the strongest ROS scavenging capacity. Principal component analysis (PCA) identified key physiological and biochemical traits, including chlorophyll stability index, proline accumulation and antioxidant enzyme activities, as significant contributors to drought tolerance. Strong correlations between these parameters and grain yield highlight the critical role of oxidative stress mitigation and osmotic adjustment in maintaining stability of yield under drought scenarios. These findings emphasize the importance of physiological, biochemical and antioxidant mechanisms in enhancing drought resilience and provide valuable insights for breeding drought-tolerant wheat genotypes to ensure global food security in the face of climate change.