Combining Ability of Brown-Rust Resistant Stocks of Wheat for Yield Attributes

General and specific combining ability variances and effects for plant height, days to heading, spike length, number of grains per spike, 100-grain weight and yield per plant was studied in the F₂ progenies of 15 parents crossed in all possible ways, excluding reciprocals. Both additive and non-additive variances were significant for all the characters. Plant height, number of tillers per plant and spike length were mainly under the control of additive genetic variance. Yield per plant was found to be controlled by non-additive gene effects. For days to heading, number of g ains per spike role of both additive and non-additive gene effects was indicated. General combining ability effects indicated that nc ne of the parents was good general combiner for all the characters. However, use of ‘IWP 500’ and ‘IWP 503’ is suggested as they showed high gca effects for earliness, spike length, 100-grain weight and yield per plant, simultaneously.