Effect of drought stress on physiological parameters in sorghum: Adaptive changes and correlations with yield under water stress conditions

Abstract

Sorghum (Sorghum bicolor L. Moench) is a crucial cereal crop in India, grown in both kharif and rabi seasons. Adequate soil moisture is essential for optimal yield, particularly in arid regions where drought and abiotic stresses can severely impact crop performance. This study aimed to identify drought-tolerant sorghum genotypes by evaluating their physiological responses under varying moisture conditions. Conducted over two rabi seasons (2021-22 and 2022-23), the experiment used a split-plot design with two replications, evaluating twenty sorghum genotypes under rainfed and irrigated conditions. Key physiological parameters, including chlorophyll content and relative water content (RWC), were assessed. Results indicated significant variability among genotypes in terms of adaptability to water stress. The Chitapur-L genotype showed a 14% and 18% decrease in total chlorophyll content at 60 and 90 days after sowing, respectively, under rainfed conditions. The ICSR-15001 genotype had the lowest mean RWC at 90 days, reflecting poor water retention. In contrast, Basavan moti demonstrated minimal RWC reduction (4.5%) under rainfed conditions, highlighting its superior water retention capability. Tandur L exhibited a significant 17% reduction in leaf RWC at 90 days under rainfed conditions. These findings offer insights into the morpho-physiological traits of sorghum genotypes, facilitating the selection of drought-resistant varieties. M-35-1, BJV 44, Basavan moti, DKS-35, and Phule Anuradha emerged as drought-tolerant genotypes, while M-148-138 and Chitapur L were identified as susceptible to moisture stress.