-

In order to investigate heritability and gene action for resistance to wheat brown rust, two resistant cultivars, N-75-15 and N-75-20, were crossed with a susceptible one. Parents, F1¬, F2 and F3 generations were planted in a randomized complete block design. Susceptible cultivar, that was planted among experimental materials and around the feild, was inoculated with a isolate of the pathogen at three times. Generation mean analysis was performed for infection type, final coefficient of infection, area under disease progress curve and relative area under disease progress curve. The study of mode of gene action by analysis of generation mean showed that in controlling traits additive, dominance and epistasis effects had main role, but dominant variance was more important than additive variance. At crosses of N- 75 –15× Boolani and N-75-20 × Boolani, at least one resistant gene was estimated for infection type and final coefficient infection and at least four and five resistant genes were estimated for AUDPC and r AUDPC .