Possible Effect of Abiotic Environmental Factors on Changes in Wheat Resistance to Leaf Rust

Possible influence of ۳ abiotic environmental factors (temperature, nitrogen salt, and benzimidazole) on wheat resistance to Puccinia triticina was studied. Under the effect of these factors, statistically significant decrease in the rust development was revealed for ۶ wheat varieties. Specific changes of virulence in ۶ pathogen monopustule isolates under the effect of those factors were revealed with high frequencies. Subjected to a particular factor, we observed an absolute coincidence of the infection types of seedlings infected with rust pathogen clones multiplied in the absence of this factor, and infection types of leaves, incubated in the absence of the factor, but infected with isolates, multiplied in the presence of this factor. Six subpopulations of the pathogen representing mixture of genotypes virulent to ۲ wheat varieties under certain conditions were created. We did not find significant differences in two disease development indexes (number of pustules and uredospores’ number in pustule) in seedlings affected by a factor and infected with subpopulations multiplied in the absence of the factor, and disease development indexes in leaves not subjected to the factor but inoculated with subpopulations multiplied in the presence of this factor. According to the results, the influence of studied factors on expression of specific (vertical) and non-specific (horizontal) wheat seedling resistance to rust was not revealed. Obviously, significant decrease in the rust development under the effect of studied environmental factors is primarily (if not only) related to their influence on the pathogen virulence and aggressiveness.

کلیدواژه ها:

Race-specific resistance ، Pathogen virulence ، Pathogen aggressiveness ، Disease development indexes.