Drought tolerance screening of rice genotypes in mid-hills of Nepal using various drought indices

Drought is a major abiotic factor causing rice yield loss in rainfed and drought-prone areas, so screening of the cultivars for drought tolerance is crucial. Our study screens 10 commercial rice cultivars grown in the mid-hills of Nepal and four pipeline genotypes. Our objective is to identify the superior drought-tolerant cultivar and suitable indices for screening. The 14 rice genotypes were evaluated under both drought stress and non-stress conditions in randomized complete block design with three replications. The yield reduction for the cultivars ranged from 12-54% during water-stressed conditions. The drought indices mean productivity, geometric mean productivity and stress tolerance index showed a positive and high correlation with grain yield. Based on drought indices, genotype NR 119 showed the highest mean productivity, geometric mean productivity, stress tolerance index and lowest yield loss. Further, principal component analysis bolsters our results by clustering similar drought indices and drought-tolerant cultivars. The NR 119 is followed by Chaite 5 and Chaite 4 as a drought-tolerant genotype, therefore, we recommend it for drought-prone areas of the mid-hill region of Nepal. We identified mean productivity, stress tolerance index and geometric mean productivity as important drought indices, so we recommend using this for drought screening.