A method for assessing resistance to the snow moldsTyphula incarnataandMicrodochium nivalein winter wheat incubated at the optimum growth temperature ranges of the fungi

摘要

Studies were carried out to determine whether incubation of wheat plants at the temperatures optimum for growth of fungi could reduce the time normally required for determination of resistance toTyphula incarnataandMicrodochium nivalein wheat, comparing with conventional under-snow incubation methods in field plots.Typhula incarnataproduced greater damage to the winter wheat plants at temperatures of 5 and 10 deg;C thanM.nivale. At 15 and 18 deg;C, there existed little difference in virulence and we could complete incubation in a period of weeks. Incubation of the plants for varying periods of time was of use for quantitative determination of the degree of resistance expressed as LI50(the number of incubation days when 50 of the plants are killed) values. The relative order of resistance among cultivars of wheat was consistent with that obtained from an under-snow incubation method. The new technique permitted wheat breeders to screen genotypes of wheat for resistance to snow mold pathogens in a shorter period, with less expensive facilities than the conventional "snow mold chamber method."