Barley Yellow Dwarf of Winter Wheat: Effects on Germplasm, and Inheritance, Combining Ability, and Reciprocal Effect for Tolerance to the Barley Yellow Dwarf Virus
Investigation of the effects of the barley yellow dwarf virus (BYDV) on winter wheat germplasm showed fall infection to be more devastating than spring infection, reducing grain yield an average of 61% vs. 38% for spring infection. BYDV also decreased winter survival, plant height, number of heads, and kernel weight. Among 1700 winter wheat entries screened, none were found to possess outstanding tolerance, though genetic variability for tolerance to the virus exists and seems to be quantitatively inherited. Heritability of tolerance is low under both fall and spring infection, but is higher under fall than spring inoculation. An interaction of entries with time of inoculation (fall vs. spring) suggests entries show differential tolerance to fall and spring times of infection. In a 12-parent diallel mating design which included reciprocal crosses in both F(,1) and F(,2) generations, reciprocal effect accounted for very little of the variability among entries for tolerance to BYDV. General combining ability and specific combining ability mean squares were highly significant, with general combining ability accounting for more of the entry sums of squares. Parental tolerance to BYDV is a good indicator of worth as a parent, especially if the parent is very tolerant or very susceptible. General combining ability for grain yield is not related to general combining ability for tolerance to BYDV when yield of infected as percent of the control treatment is the measure of tolerance. Therefore, breeding for high yield will not lead to less yield loss under BYDV infection. There is a general agreement between combining ability effects in fall and spring inoculated treatments, leading to the conclusion that one should be able to test and develop tolerant varieties under one environment which are tolerant in the other environment.
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign