Late sowing and drought under late sown conditions of wheat are the major constraints on wheat production in South Asian countries. The yield of wheat is significantly reduced due to the lack of irrigation water and temperature-induced late sown in Nepal. To identify late sown drought tolerant genotypes of wheat a field experiment was conducted using twenty elite wheat genotypes at the Institute of Agriculture and Animal Science (IAAS), Paklihawa Campus, Nepal in an alpha lattice design with two replication using ten stress tolerance indices (STIs) (Tolerance Index (TOL), Mean Productivity (MP), Stress Susceptibility Index (SSI), Geometric Mean Productivity (GMP), Stress Tolerance Index (STI), Yield Stability Index (YSI), Modified Stress Tolerance Index 1 (MSTI 1), and Modified Stress Tolerance Index 2 (MSTI 2)). NL 1368 and Bhirkuti was found to have highest yield under late sown and drought under late sown condition. The grain yield was found to be reduced from 10.7% to 43.1 % under late sown drought conditions with a mean reduction of 23.67% in comparison with late sown condition showing a direct effect of drought under late sown condition on grain yield of wheat. Correlation analysis showed, yield at late sown condition and yield at drought under late sown condition were significantly positively correlated to MP, GMP, STI, MSTI1, and MSTI2. Principal component biplot analysis showed, Yp and Ys both were positively correlated with MP, GMP, MSTI1, and MSTI2. Hence, selection based on MP, GMP, MSTI1, and MSTI2 would give a high-yielding genotype under both conditions. The first two principal components cumulatively explains 98.720% of total variation for stress tolerance indices and Bhirkuti, BL 4919, NL 1368, and NL 1376 were found to be high yielding potential genotypes across both environments. Thus, these can be used as a genetic material for yield improvement in wheat.
biplots, high yielding, improvement, principal component analysis, tolerance