Effect of Drought Stress on Antioxidant Expression, Growth and Yield in Sorghum

Drought stress presents a major constraint to sorghum (Sorghum bicolor L. Moench) production, particularly in arid and semi-arid regions, where water scarcity significantly impairs plant growth, physiology, and grain yield. This study investigated the response of two sorghum varieties (SAMSORG 17 and CSH 14) to controlled drought durations of 5, 10, and 15 days under screenhouse conditions. Growth parameters, yield components, and biochemical traits including total phenolics, flavonoids, carotenoids, vitamins C and E were evaluated to determine the plant’s physiological and antioxidant responses. The results showed a consistent decline in growth and yield with increasing drought severity, while antioxidant levels increased significantly, peaking after 10 days of water stress. variety A (SAMSORG 17) showed higher levels of phenolics (10.63 mg GAE/g), vitamin C (96.63 mg/100 g), and vitamin E (0.28 mg/100 g), whereas variety B recorded elevated flavonoid (6.72 mg QE/g) and carotenoid (0.186 mg/100 g) contents. Statistical analysis confirmed significant treatment effects (p < 0.001) across all measured indices. These findings suggest that moderate drought enhances sorghum’s antioxidant potential without drastically compromising growth, and that genotypic variation plays a role in differential drought adaptation. We conclude that both varieties show potential for drought resilience, with distinct antioxidant strengths. Further research should focus on molecular mechanisms underlying these responses and validate results under field conditions to support climate-smart sorghum improvement and nutritional biofortification.