GENETIC ANALYSIS OF RESISTANCE OF WHEAT TO SCAB

In 1979 and 1983-86, the breeding materials and hybridization crosses of wheat were inoculated and identified on scab resistance. Investigation on 71 crosses indicated that the scab resistance tended to resistant parents with F1 hybrids,which were derived from the crosses of resistant variety? susceptible variety and which showed dominant effect.Scab displayed continuous distribution with F2 generations, which also showed dominant effect.The resistance of wheat to scab mainly showed partially dominant effect.The heritability of resistance to scab was somewhat low-er; the average heritability in a broad sense was 45.14% in 18 crosses. However,the differences were large between the corsses,ranging from 9.05 to 73.53%.The resistance of F1 was positively correlated with resistant parents, susceptible parents and the meanparent values. The correlation coefficients were 0.4616**and 0.4627** between F2 plants and F3 families. Selecting the single plant at earlier stage was effective to a certain degree, but progenies should be identified and selected continuously.