Identification of drought tolerant wheat (Triticum aestivum) genotypes using stress tolerance indices in the western terai region of Nepal

Abstract

Drought is the leading abiotic factor influencing global wheat production. To evaluate the drought performance of wheat genotypes, it is essential to identify and employ stress tolerance indices. These indices are essential for evaluating variation among genotypes in their response to drought, ultimately contributing to the development of more resilient and sustainable wheat production systems worldwide.. Thus, a field experiment was conducted in alpha lattice design with twenty genotypes including three checks viz., Bhrikuti, Gautam, and RR 21 at Institute of Agriculture and Animal Science (IAAS), Paklihawa Campus, Rupandehi, Nepal, under irrigated and drought conditions, to identify drought tolerance wheat in winter season of 2022. In irrigated condition, five irrigations were applied at different critical growth stages. Whereas in drought conditions, only initial irrigation was applied after field preparation, for the germination of seed, and a poly house was constructed, to restrict all forms of natural precipitation. Genotypes were harvested when they attained harvestable maturity, grain yield was recorded, and stress tolerance indices were calculated. The mean grain yield reduction was 86.88 % in drought condition. Correlation analysis showed that Yield under Stress conditions (Ys) had a significant positive correlation with Yield Stability Index (YSI)(0.911**), Geometric Mean Productivity (GMP)(0.918**), and Stress Tolerant Index (STI)(0.911**). Thus, YSI, GMP, and STI are the important stress tolerance indices considered while selecting drought tolerance genotypes. Principal component and biplot analysis revealed that Bhrikuti, BL 5116, NL 1447, NL 1508, and Gautam were stable and high-yielding drought tolerant wheat genotypes.