Development of yellow rust resistant doubled haploid lines of wheat through wheat ´ maize Crosses

In order to produce doubled haploid lines of bread wheat resistant to strip or yellow rust, three F1 wheat hybrids were crossed using pollens of three maize hybrids. Out of 1071 pollinated florets, success in seed set ranged from 63.1% to 93.3% (mean 78%). Differences in seed set among the crosses were not significant. Embryo formation in the seeds developed on different crosses also varied from 17.2% to 60.7% (mean 27.4%). Embryos continued to develop up to 16 days when 2, 4-D was applied after pollination. One hundred three out of 211 embryos cultured, of which 42.7% developed into plants. Colchicine treatment resulted in diploidization and seed production on 56% of plants. Significant variation was observed among wheat genotypes in the frequency of DH plants (overall success). There were no significant differences among crosses dependent on various maize genotypes, indicating non-influence of maize genotypes. Response to yellow rust of 51 DH lines was assessed along with two parental cultivars, 'MV17' (a Hungarian cultivar resistant to the yellow rust pathotypes prevalent in Iran), and 'Falat' (a susceptible cultivar) and the check variety 'Bolani' at seedling stage in greenhouse. Resistance was evaluated in terms of infection type, latent period, pustule size, and pustule density using the most virulent race of yellow rust in North- west of Iran, 166E134A+. Analysis of variance showed significant differences among the DH genotypes for all the resistance parameters. The results demonstrated the high effectiveness of the method to produce yellow rust resistant homozygous wheat genotypes in short time by doubling of haploid lines generated through pollination of wheat F1 plants with maize pollens.