Genetic analysis of septoria leaf blotch resistance in wheat at seedling stage

Septoria tritici Blotch (STB) was enumerated as the most important disease in which is responsible for abundant losses in wheat product. In this study, three spring wheat varieties and a resistant line of International Center Agriculture Research in Dry Area (ICARDA) were evaluated in a genetic design of the generation mean analysis, in order to study the existence of resistance to STB disease and genetic analysis of resistance at seedling stage in greenhouse. Therefore Six basis generations included parental varieties, F1, F2 and Backcrosses (BC1 & BC2) were planted in Completely Randomized Design (CRD) at the greenhouse. Result of generation mean analysis in resistant line×tajan cross indicated manifest roles of additative effects in controlling the necrose and necrose Area Under Disease Progress Curve (nAUDPC) traits. Also in this cross For picnid and picnid Area Under Disease Progress Curve (pAUDPC) traits the roles of dominance effects were more pronounced. In the crosses of the resistant line×Moghan and Morvarid×Moghan roles of dominance effects is much more than additive effect and noallelic interaction dominance×dominance was contributed significantly in all traits. High estimate of dominance and epistatic effects emphasized on hybrid seed production as trait breeding strategy, also indicated that selection should be delayed after several generations of selection such as single seed descent until a high level of gene fixation is attained. effective factors controlling resistance to STB disease was varied between 1 and 3 in various cross.