Breeding for Climate Resilience in Wheat Under Irrigated, Heat Stress, Rainfed and Drought Environments

The changing climatic patterns along with increase in temperature and decrease in rainfall had emerged as a significant threat to the wheat production worldwide. Hence, the concern toward climate resilient wheat genotypes has increased greatly in last few decades. To identify the traits governing high yields and adaptability under irrigated, heat stress, rainfed and drought environments, a field experiment was conducted in the western terai region of Nepal during 2022 and 2023. The additive main effect and multiplicative interaction (AMMI) model ANOVA showed, all the quantitative traits studied were mainly affected by environment, followed by genotypes and interaction factor. The overall wheat productivity was reduced by 31.1, 64.4 and 88.2% under heat stress, rainfed and drought environment, respectively. The result indicated the need of climate resilient breeding in wheat. Correlation, path and principal component analysis (PCA) revealed; ten spike weight (TSW) and grains per spike (NGPS) had the smallest vector angle with grain yield under irrigated, while thousand kernel weight (TKW), days to booting (DTB), days to heading (DTH) and days to anthesis (DTA) under rainfed environment. Contrary to rainfed, the vector angle was maximum with DTB, DTH and DTA under heat stress environment. Similarly, smallest vector angle with spike length (SL) and spikelets per spike (NSPS) was observed under drought environment. Earliness was found to favor heat stress environment, while lateness favored rainfed. Similarly, NL 1488, NL 1506, NL 1492 under irrigated; NL 1488, NL 1512, Gautam under heat stress; NL 1508, NL 1504, BL 4984 under rainfed and NL 1445, BL 5116 under drought environment lied in the high yielding quadrant in PCA biplot. Hence, these selected traits and genotypes had overall higher adaptability over two wheat growing seasons, and these genotypes should promoted in varietal improvement program to release as a potential climate resilient variety.