ORIGINAL ARTICLE

Selection of High Yield M6 Wheat Mutant Lines Obtained from Stem Rust Resistant Parents

Wheat is a major cereal crop grown worldwide. Mutation breeding with the objective to improving grain yield was performed for selection of mutant lines. Dry dormant seeds with approx. 11 % moisture of three Australian genotypes (Mendos, Coorong and Egret) were treated with 100, 160 and 200 Gy Co-60 gamma radiation and mutants were selected between the M1 and M5 generations for yield production under field experimental conditions. Decrease in survival rate (%) of plants was observed. Five seeds from each spike per plant of M1 plants were collected, bulked dose-wise and grown separately as M2. Fifteen promising mutant lines retested in a M5-trial for yield in comparison with the parent cultivars. Significant differences (P<0.05) in 1000-grain weight and grain yield were detected among mutants, with values being consistently higher in promising mutants lines than in the test cultivars. Higher mean grain yield were found in the two promising mutants C-17-3 (1061 g/m²) and C-17-31 (976 g/m²) as compared with their mothers and the local control genotype Bouhouth10 (857 g/m²). The obtained results suggest that LD₅₀ (160 Gy) gamma radiation treatment can be useful from breeding point of view for selecting higher yielding wheat plants, and the results showed that the Australian parents had Sr26 resistance gene against stem rust disease caused by Puccinia graminis f. sp. tritici, therefore, their utilization is suggested in wheat breeding programs to achieve resistant cultivars.