Genetic protection of wheat from leaf and stem diseases in the Volga region – problems and prospects

In the conditions of changing climate and emergence of new virulent pathotypes of pathogens, advanced breeding for resistance is of primary importance. Its strategy includes both studying the pathogen by virulence, tracking new pathotypes, migration routes, determining effective resistance genes; and analysis of resistance of varieties and lines, identification of known resistance genes, search for new genes and introduction of effective resistance genes into adapted germplasm. Wheat (Triticum spp.) is one of the most important grain crops for humans. In Russia, the main grain-producing regions are Western Siberia, Krasnodar Krai and, of course, the Volga region. Stem and leaf rust, powdery mildew and tan spot are dangerous diseases of wheat, common in the Volga region, causing crop losses and reducing grain quality. The causative agents of the diseases are basidiomycetes Puccinia graminis f. sp. tritici (stem rust), P. triticina (leaf rust) and ascomycete fungi – Pyrenophora tritici-repentis (Drechslera tritici-repentis) (tan spot) and Blumeria graminis f. sp. tritici (Erysiphe graminis) (powdery mildew). This review systematizes modern data on the harmfulness of these pathogens, the features of their biology and pathogenicity factors. Particular attention is paid to the analysis of world and Russian studies of the population structure of phytopathogens based on virulence and DNA markers. Data on the racial composition of the Volga region fungal populations, R-genes effective against them, and the resistance of wheat varieties approved for cultivation in the Volga region are presented. The article summarizes information on the genetics of resistance of bread wheat to the diseases under consideration, including a description of known resistance genes and their sources. The problems and prospects of using these genes in breeding programs to create resistant varieties are considered.