Evaluation of drought-tolerant rice (Oryza sativa L.) genotypes under drought and irrigated conditions in Bhairahawa, Nepal

Abstract

Rice production can be severely affected by drought stress and this could cause massive economic losses every year. Global climate change is steadily becoming an important issue. This research was conducted in order to identify drought-tolerant rice genotypes using stress tolerance indices. Employing a randomized complete block design, a total of nine rice genotypes were assessed under irrigated and drought-stress conditions from June to November 2022 at the Institute of Agriculture and Animal Science (IAAS), Paklihawa, Nepal. In particular, the stress susceptibility index (SSI), mean productivity (MP), and geometric mean productivity (GMP) revealed strong and highly significant positive correlations to agricultural yields under both irrigated and drought stress conditions. The stress tolerance index (STI) and yield stability index (YSI) showed strong and highly significant positive correlations to yield under drought conditions while the tolerance index (TOL) and yield index (YI) showed strong and negative significant associations to yield under stress conditions. The highest STI, GMP, and MP were observed in the IR16L1713 genotype followed by IR17L1387, establishing these two as the steadiest and most efficient genotypes among nine genotypes of rice. These genotypes have the potential to be selected for maximum outputs under both irrigated and drought-stress situations. A biplot analysis showed a positive association of MP, GMP, and YI to rice yields in an irrigated environment and a negative correlation of SSI, STI, and TOL, with a reduction percentage in a drought-stressed environment. Therefore, these stress indicators can be used to evaluate rice genotypes under both normal and drought stress settings.