Estimation of gene effects and combining ability of latent period of stripe rust in advanced lines of wheat

Four advanced breeding lines of wheat which had appeared to be resistant to stripe rust in the past years along with a susceptible variety, Bolani, were intercrossed in all combinations of a halfdiallel design. Seedlings were grown in a greenhouse until the first leaves fully expanded and then inoculated with two pathotypes (races) 6E134A^+ and 134E148A^+, separately. Days to the first pustule eruption was recorded as the latent period. Diallel analysis was performed by two methods of Griffing and Jinks and Hayman. M-78-1 and M-78-10 were known as the best general combiners for the longer latent period. Results of the analysis of variance of Wr+Vr and Wr-Vr, Wr/Vr regression analysis and estimates of genetic parameters indicated the importance of both additive and nonadditive gene effects. Broad-sense heritability was 98% for both pathotypes. Narrow-sense heritability was 65% and 80% for 6E134A^+ and 134E148A^+ pathotypes, respectively.