Yield Performance Evaluation of Thirty Spring Rice (Oryza sativa L.) Cultivars Under Terminal Drought Conditions Using Various Drought-Tolerant Indices

An experiment was conducted from February 19, 2022, to July 4, 2022, in the farmer's field of Itahari Sub-metropolitan city in Nepal under well water and drought conditions to screen thirty drought-tolerant spring rice (Oryza sativa L.) genotypes using various drought tolerant indices for its cultivation under rainfed and drought areas. Analysis of variance revealed that grain yield under both conditions were significantly different and yield under well-watered condition was higher than yield under drought condition. The greater value of tolerance index (TOL) was reported in Chaite-2 and IR-80991-B330-0-2 and the minimum value of TOL was reported in IRE16L1661 and IR16L1004. The lowest value of stress susceptibility index (SSI) was reported in IRE16L1661, the maximum value of yield susceptibility index (YSI) was reported in IRE16L1661, and the maximum values of mean productivity index (MP), geometrical mean productivity (GMP), and stress tolerance index (STI) were reported in IRE 1621661. Correlation analysis revealed that the high-yielding genotype under well-watered conditions also yielded higher under-stress conditions. For grain yield, analysis of variance and principal component analysis revealed that IRE 1621661 is suitable for both conditions and genotype IRE16L1661 is stable under drought conditions based on drought tolerance indices. Thus, these two genotypes can be recommended under drought stress in the inner plains of Nepal with appropriate agronomic practices.