Assessment of agro-morphological traits and yield-based tolerance indices in sesame (Sesamum indicum L.) genotypes under drought stress

Sesame (Sesamum indicum L.) is one of the most important oilseed crops of the world, particularly tropical areas. Its production is significantly affected by drought stress. The present study was performed to assess the efficiency of existing criteria for the selection of tolerant cultivars while evaluating sesame genotypes under drought conditions. Various agro-morphological traits along with some drought tolerance indices were used to evaluate 15 sesame genotypes under drought conditions. A moderate to high heritability was estimated for plant height (0.55), no. of capsules (0.72), capsule diameter (0.60), no. of seeds per capsule (0.43) and seed yield (0.53). On average, the seed yield of genotypes was reduced by 45% under water stress. Seed yield was significantly positively correlated with the no. of capsules, capsule diameter, and no. of seeds per capsule under both normal and drought conditions. The number of capsules and capsule diameter were suggested as potential criteria for indirect yield selection under drought stress. Chinese (G01), Naz Chand Shakhe (G05), and Darab1 (G04) genotypes were identified as the most tolerant based on the average ranking of indices. Stress/non-stress production index (SNPI), yield index (YI), and drought resistance index (DI) were suggested as the most efficient drought tolerance indices according to principal component analysis and correlations. The evaluation criteria proposed in this study can be used for efficient selection of drought-tolerant genotypes in sesame. Moreover, reported tolerant and sensitive genotypes can be used in future studies and breeding programs in sesame under drought stress.