Study on inheritance of resistance to Septoria tritici Blotch in wheat by Generation mean analysis

To study inheritance of resistance to septoria tritici Blotch in wheat, the generation mean analysis method was used. So six generations (P1, P2, F1, F2, BC1 and BC2) were planted under completely randomized design with three replications in greenhouse. Seedlings were inoculated at the second-leaf stage with an isolate of Septoria tritici and Necrosis and Picnidia density and Area Under Disease Progress Curve for both traits (Necrosis and Picnidia) were evaluated. Results of generation mean analysis showed that the additive, dominance and epistatic effects were effective in all traits, but the role of dominance effects and dominance × dominance interactions was more important. The results of the estimated degree heterosis and potance ratio confirmed the more importance of dominance effect in genetic control of studied traits. Average broad sense heritabilities were between 73 and 93.6 for all traits. Degree of dominance being more and less than one, confirmed dominance and overdominance gene effects. Therefore, it is recommended to use the breeding methods based on hybridization and or selection in final generations to improve resistance to Septoria tritic blotch.