Amelioriative effect of salicylic acid on rabi sorghum under drought stress

Abstract

A field experiment was conducted during the Rabi season of 2024-25 at Mahatma Phule Krishi Vidyapeeth, Rahuri, to standardize the optimum concentration of salicylic acid under drought stress in sorghum (Sorghum bicolor (L.) Moench). Two contrasting rabi sorghum varieties, Phule Yashoda (drought tolerant) and Phule Revati (drought susceptible), were grown under normal and drought conditions imposed using a rainout shelter. Foliar application of SA at 0, 0.25, 0.50, 0.75, and 1.0 mM was carried out at 20, 40, and 60 days after sowing. Drought stress significantly reduced relative leaf water content (RLWC) and chlorophyll content while increasing lipid peroxidation, with greater damage observed in Phule Revati. Application of SA, particularly at 0.50-0.75 mM, effectively mitigated drought effects by improving RLWC, maintaining chlorophyll content, enhancing proline accumulation, and stimulating antioxidant enzymes (SOD and CAT), thereby reducing oxidative damage. Phule Yashoda exhibited higher inherent tolerance, whereas Phule Revati showed greater relative improvement in response to SA treatment. Overall, foliar application of salicylic acid at 0.50-0.75 mM proved effective in enhancing physiological and biochemical tolerance of rabi sorghum under drought stress.