Expression and association of quantitative traits of wheat (Triticum aestivum L.) genotypes under different wheat growing environments

Climate-resilient wheat genotype plays a crucial role in food and nutritional security of the world. The production of wheat is mainly limited by abiotic stresses such as heat stress and drought. To identify the most appropriate trait for the selection of high yielding genotypes under heat stress (HS) and heat drought (HD) environment, a field experiment was conducted in the western region of Nepal during the wheat growing season of 2021-22 to 2022-23 comprising 20 wheat genotypes under alpha lattice design. The additive main-effect multiplicative interaction (AMMI) and combined analysis of variance (ANOVA) showed environment had the most substantial effect on the expression of the quantitative traits studied with 24 and 48% yield reduction under HS and HD environments, as compared to irrigated. PCA extracted, days to booting (DTB), days to heading (DTH), days to anthesis (DTA), booting-anthesis duration (BtoA), spikelets per spike (NSPS) under irrigated; DTB, DTH, DTA, 10 spike weight (TSW), thousand kernel weight (TKW) under HS; and DTB, BtoA, spike length (SL), TSW under HD environment. Phenotypic correlation and path analysis revealed, to get high yield, selection can be done with DTB, DTH, DTA, booting-heading duration (BtoH), BtoA, plant height (Ph), spikes per meter square (NSPMS), SL, and TKW. Early booting and heading genotypes with longer spikes, more tillers, grains per spike, and seed weight benefits all environments. Extended booting-heading and booting-anthesis duration with shorter heading-anthesis duration are advantageous as well. Taller genotypes yield more under HS and HD environment whereas shorter genotypes are productive under irrigated.