Biradar, Suma S.Deepak D.A.2021-07-162021-07-162016-08https://krishikosh.egranth.ac.in/handle/1/5810170583The uncertainty of sufficient moisture availability necessitates the development of wheat varieties for drought situation. The main objective of this investigation was to dissect out the drought tolerance mechanisms in different genetic backgrounds by conducting separate experiments using hundred genotypes in drought and irrigated condition by following alpha lattice design during rabi 2015-16. The traits like leaf waxiness, ground cover, tillers per meter and grain yield exhibited high GCV and PCV. High heritability coupled with high genetic advance as per cent mean were observed for traits like plant height, leaf waxiness, spike length, tillers per meter, grains per spike and grain yield. The indices viz., Stress Susceptibility Index (SSI) and Stress Tolerance Index (STI) were adopted to identify drought tolerant genotypes. Ten genotypes based on SSI and five genotypes by STI, were identified as drought tolerant. It is interesting to note here that drought tolerant genotypes identified in the present investigation exhibited comparable root parameters with standard checks along with other physiological parameters. Among which, early vigour, early completion of life cycle, higher flag leaf chlorophyll content, high membrane stability, root length and root volume contributed to drought tolerance under different genetic backgrounds. The traits viz., spike length, thousand grain weight, spikelets per spike, relative water content and tillers per meter were found to be least sensitive for moisture stress and exhibited high genetic diversity. It is deduced from both the indices that the genotype UAS 323 recorded higher yield under moisture stress which was manifested by higher spike length, thousand grain weight, grains per spike and biomass. Markers xbarc319, xgwm626, xgwm540, xgwm557, xwmc323 and xwmc634 showed polymorphism and can be further validated. Thus, identified trait specific drought tolerant genotypes can be used to identify QTLs with the help of molecular markers.EnglishThesis