Character association studies in Bread wheat genotypes for early heat tolerance and grain micronutrient content

Abstract

Thirty bread wheat genotypes were tested by adopting Randomized Block Design with three replications during 2019-20, under two different environments, i.e. early and timely sown conditions. The ultimate goal was to determine the relationship between yield and yield contributing traits and classify traits that have the highest direct and indirect effects on grain yield under both environmental circumstances. Grain yield was positively and significantly correlated with no. of tiller/plant, no. of grains/spike, relative water content, spike fertility, harvest index, grain zinc content and chlorophyll content at the level of both genotype and phenotype; conversely, found significantly negative with canopy temperature and non-significant with days to 50 % flowering and seedling length. Under stress condition, the correlation for grain yield/plant was found significant, and it was correlated positively with no. of tiller/plant, spike fertility, relative water content, harvest index and grain zinc content and non-significantly with seedling length, no. of grain/spike, chlorophyll content, flag leaf area and thousand-grain weight. At the level of both genotype and phenotype, grain yield per plant had a high direct effect in the positive direction by harvest index followed by no. of tiller/plant, no. of grain/spike, relative water content. Thus, more weightage should be given towards these traits as selecting these traits can be rewarding to achieve high yielding wheat genotypes.