Evaluation of Drought Tolerant Rice Cultivars Using Drought Tolerant Indices under Water Stress and Irrigated Condition

Drought is the most critical abiotic factor reducing rice yield in rainfed and drought prone areas. Majority of rice cultivated area in south Asia are under rainfed, where water stress at any of the critical growth stage causes sharp decline in yield. Research was conducted in western Nepal at farmers field around the close vicinity of Regional Agriculture Research Center (RARS) Nepalgunj. Ten different rice cultivars were evaluated under drought stress and non-stress condition during the year 2017 to identify superior stress tolerant cultivars. Different drought tolerance indices like stress tolerance (TOL), Stress tolerance index (STI), Stress susceptibility index (SSI), were tested in screening superior rice cultivars. Significant reduction in mean grain yield was observed under drought stress in all rice cultivars under the study. The rice cultivars with high STI values and low TOL and SSI were identified as superior drought tolerant cultivars. Based on results of different tolerance indices, Sukha series of rice, Sukha Dhan 1-6 and Radha-4 showed low TOL and SSI and high STI values and were identified as drought tolerant cultivars. The present study reveals that selection based on drought tolerance indices can be an efficient tool in identification of superior drought tolerant cultivars with higher yield and stability.