Влияние сортов озимой пшеницы с разными типами устойчивости к возбудителю бурой ржавчины на изменение структуры популяции по признаку вирулентности

Abstract

Abstract. A change in the varietal composition of wheat causes response changes in the population of the fungus, which evolves conjugately. Population studies of the causative agent of leaf rust of wheat are carried out in many countries. Comparison of populations of P. triticina is mainly carried out geographically. The purpose of the study was to analyze the dynamics of the virulence of North Caucasus Puccinia triticina populations under the influence of winter wheat varieties with different types of leaf rust resistance. Methods. The study was carried out in 2018 in the experimental field and greenhouses All-Russian Research Institute of Biological Plant Protection. Two varieties of winter wheat: Kralya and Vershina with different types of resistance to leaf rust, were used for the experiment. Cultivar Kralya had race-specific resistance; cultivar a Vershina had race-nonspecific resistance to leaf rust. Virulence analysis of the impact of each cultivar on the structure of the pathogen population based on the results of differentiation of P. triticina populations, collected from each cultivar and compared to the mixed pathogens population. As a result, it was found that the genotype of a winter wheat variety with race-specific resistance significantly affects the virulence of the P. triticina population. The frequency of virulent pathogen isolates to most lines with Lr genes has changed under the influence of driving selection. Therefore, the wide regionalization of varieties with race-specific resistance will contribute to selective pressure on the P. triticina population and the accumulation of virulent phenotypes in it. The genotype of a wheat variety with nonspecific resistance did not cause significant changes in the gene pool of the virulence of the leaf rust pathogen population. In accordance with the obtained values of the Nei index, the pathogen population collected from a variety with race-specific resistance has significant differences with the combined population (N = 0.68), in contrast to the population of P. triticina collected from the Vershina variety (N = 0.41). The results obtained confirm the importance of screening varieties by resistance types for further decision making on their placement. Varieties with race-specific resistance are best used for mosaic placement with subsequent mandatory rotation in time and space. And varieties with nonspecific resistance, which are weakly affected by all races of the pathogen and cannot be carriers of infection, can be used over large areas for a longer time, combined with varieties from various groups, including their own. Scientific novelty. There have been practically no studies on the effect of wheat varieties with different types of resistance on the virulence of rust fungi populations, although this direction is of great practical interest for both selection and varietal placement.