Abstract: Disease-resistance character of wheat germplasms was identified using 3×4 incomplete diallel model and weighted least square method in all F₁,and in six generation reserved combinations of 3 BYDV-resistance material females and 4 fertility variety males.The least gene number was estimated in the disease-resistance trait by Castle-Wright method.Results show that inheritance does not follow additive-dominant genetic model,while additive effects remain significant.Meanwhile significant interactions are found with additive×additive and additive×dominant.Heritability of BYDV resistance is high and within the range of 69.15%～97.75%.02R084 and 02R493 are estimated to contain one resistance gene,and gene interactions vary with different genetic backgrounds.