Effects of hydrogen peroxide application on agronomic traits of rice (Oryza sativa L.) under drought stress
Drought stress is a major environmental factor limiting crop growth and productivity. Hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) plays an essential role during stress response by acting as a signal molecule that activates multiple stress tolerance mechanisms. In this study, the effects of H<sub>2</sub>O<sub>2</sub> on agronomic traits were studied in rice (Oryza sativa L.) cv. Khao Dawk Mali 105 (KDML 105) was subjected to drought stress. H<sub>2</sub>O<sub>2</sub> was applied by either seed priming or foliar application method with a concentration of 1, 5, and 15 mmol/L. The results showed that both seed priming and foliar application with H<sub>2</sub>O<sub>2</sub> improved some yield components. The tiller numbers, number of panicles, number of filled grains, filled grain weight, and harvest index were improved approximately 1.13, 1.04, 1.23, 1.21, and 1.1 times compared to the untreated plants. Foliar application, however, helps the plant by reducing yield loss as indicated by a 0.5-time reduction in the number of unfilled grain and lower unfilled grain weight. It was suggested that 5 mmol/L H<sub>2</sub>O<sub>2</sub> was the most effective concentration to alleviate the effect of drought stress during the reproductive stage in rice.
