Generation Mean Analysis for Several Agronomic and Physiologic Traits in Bread Wheat under Normal and Water Deficit Stress Conditions

This experiment was conducted during 2013-2014 in Tabriz University research farm, Iran. In this research, the inheritance of some agronomic and physiological traits in different generations of Bam (tolerant to drought) and Artha (sensitive to drought) cross was studied in field conditions by generation mean analysis. The experiment was a split plot design using randomized complete blocks with two replications with the irrigation conditions in the main plots and generations in the sub-plots. The interaction between generations and irrigation conditions was significant only for grain yield. Based on the result of generation means analysis for the spike length and straw weight, the threeparameter model was found fitting the analysis. For the thousand-seed weight in the water stress condition and for the plant weight in the irrigation condition, a non-significant chi-square suggesting that the six-parameter model for these traits is suitable. For the other traits, the chi-square was significant in both conditions. For spike length and leaf area, the degree of dominance was greater than one (2.3 and 1.53, respectively) which showed the existence of over-dominance gene action in controlling these traits. Straw weight in normal condition, leaf area and thousand seed weight in the stress condition had a high broad-sense heritability. The narrow-sense heritability for all other traits was low, suggesting the need for exploiting dominance gene action in the breeding programs if hybrid varieties are produced in the bread wheat.