The differentiation of winter wheat (Triticum aestivum L.) cultivars for resistance to the most harmful fungal pathogens

Genetic homogeneity of wheat crops possessing inefficient resistance genes, together with large variability in the mycopathogen virulence result in increasing losses of the harvest from fungal diseases worldwide. Therefore, the persistent long-term resistance varieties are the main element in the strategy of integrated plant protection aimed at reducing risk of environmental pollution by fungicides. Updating the set of such varieties preserving efficiency in different agricultural systems, the regional planning of their placement in crops would be more effective to provide protection against mycopathogens and to constrict the spread of new virulence genes. We first performed a comprehensive assessment of resistance to major fungal pathogens for winter wheat varieties of different eco-geographical and breeding origin from the VIR World Collection (N. I. Vavilov All-Russian Institute of Plant Genetic Resources, St. Petersburg), the collections of Krasnodar Research Institute of Agriculture (KNIISH, South of Russia) and Nemchinovka Moscow Research Institute of Agriculture (MRIA, Central Russia). The goal was to select the donors of resistance to adverse biotic factors, including the most harmful diseases: brown rust ( Puccinia triticina Eriks.), stem rust ( P. graminis Pers.), powdery mildew ( Blumeria graminis (DC.) Speer f. sp. tritici Marchal.), Septoria ( Septoria tritici Rob. et Desm. and Stagonospora nodorum Berk.) from the collections of VIR, KNIISH and MRIA. Among 158 winter wheat cultivars the field resistance to leaf rust has been showed in 8.9 %, to stem rust in 5.1 %, and to Septoria spp. in 1.3 %. No wheat cultivars were resistant to powdery mildew. Evaluation of wheat seedling resistance to leaf rust in a climatic chambers allowed to identify samples with adult and race-specific resistance. The Ukrainian varieties differed geographically in resistance to the leaf rust. The varieties resistant to two or more pathogens were the most important. Cultivars Junona, Tanya (KNIISH), Bogdanka (derived from Belgorod region.) have been possessed the resistance to leaf and stem rust. Cultivars Borvij, Zagrava odes’ka (Ukraine), Catalus (Germany) were partial resistant to leaf rust and moderate susceptible to Septoria spp. Cultivars Gyrmyzy Gjul’ 1 (Azerbaijan), Catalus (Germany) were important due to their combined resistance to Septoria tritici and Stagonospora nodorum. KS 93450 (USA) has combined partial resistance to leaf rust, moderate susceptibility to Septoria spp. and stem rust resistance. These samples can be further used in breeding.