Leaf rust represents the major threat to wheat production in Russia and Ukraine. It has been present for many years and epidemics of the pathogen occur in different regions on both winter and spring wheat. In some regions there is evidence of more frequent epidemics, probably due to higher precipitation as a result of climate change. There is evidence that the virulence of the leaf rust population in Ukraine and European Russia and on winter wheat and spring wheat is similar. The pathogen population structure in Western Siberia is also similar to the European part, although there are some significant differences based on the genes employed in different regions. Ukrainian wheat breeders mostly rely on major resistance genes from wide crosses and have succeeded in developing resistant varieties. The North Caucasus winter wheat breeding programs apply the strategy of deploying varieties with different types of resistance and genes. This approach resulted in decreased leaf rust incidence in the region. Genes Lr23 and Lr19 deployed in spring wheat in the Volga region were rapidly overcome by the pathogen. There are continuing efforts to incorporate resistance from wild species. The first spring wheat leaf rust resistant varieties released in Western Siberia possessed gene LrTR which protected the crop for 10-15 years, but was eventually broken in 2007. Slow rusting is being utilized in several breeding programs in Russia and Ukraine, but has not become a major strategy.

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In this study, naturally and artificially inoculated winter wheat varieties were studied with respect to their productivity and resistance to Fusarium head blight (FHB). We used the following set of disease assessment parameters: the percentage of visually and latent Fusarium-damaged grains (FDG); the DNA content of Fusarium fungi; the productivity of inoculated plants compared with non-inoculated plants; and the amount of mycotoxins in the grain. In case of naturally infected grains, the average FDG was found to be about 6.1 % (range of 0–15 %). The amount of DNA of Fusarium graminearum was found to be in the range of (1.1–42.7) × 10–5 ng/ng wheat DNA. The mycotoxin deoxynivalenol (DON) was detected in 15 samples of grain from plants that were grown under natural infection. The maximum DON amount was found to be 420 μg/kg. Fumonisin B1 (FB1) was not be detected in naturally infected grain. In case of artificially inoculated plants, the average FDG was found to be 25.8 % (2–54 %). The amount of F. graminearum DNA was found to be significantly higher (4.24– 49.8) × 10–3 ng/ng than it was detected in grain of non-inoculated plants. The wheat varieties inoculated with F. graminearum contained DON in high amounts from 20255 to 79245 μg/kg. Furthermore, a significant amount of FB1 was detected in all wheat varieties in the range of 980–20326 μg/kg. Among the analysed wheat varieties, Adel was characterized to be the most resistant to fungal infection as well as to the contamination by mycotoxins. Antonina, Lebed and Pamyat varieties were classified more relatively resistant than that of other varieties, and Utrish variety was found to be the most susceptible to FHB. The similar resistance of wheat varieties against F. graminearum and F. verticillioides infection was recorded, and the interactions between the fungi during the colonization of grain were shown.

The Volga region is one of the main grain-producing regions of Russia. Wheat stem rust caused by Puccinia graminis f. sp. tritici is among the most destructive fungal diseases of wheat. Recently, its harmfulness has increased in the Volga region. In this regard, an analysis of the resistance and diversity of the Sr genes in the Russian wheat cultivars is necessary. In this work, 126 wheat cultivars (including 23 durum wheat cultivars and 103 bread wheat cultivars) approved for use in the Volga region were evaluated for their resistance to two samples of P. graminis f. sp. tritici populations from different Volga region areas at the seedling stage. Specific DNA primers were used to identify resistance genes (Sr2, Sr24, Sr25, Sr26, Sr28, Sr31, Sr32, Sr36, Sr38, Sr39, and Sr57). Highly resistant cultivars (30 from 126) were identified. In bread wheat cultivars, the genes Sr31 (in 19 cultivars), Sr24 (in one cultivar), Sr25 (in 15 spring wheat cultivars), Sr28 (in six cultivars), Sr38 (in two cultivars), and Sr57 (in 15 cultivars) and their combinations—Sr31 + Sr25, Sr31 + Sr38, Sr31 + Sr28, Sr31 + Sr57, Sr31 + Sr28 + Sr57, and Sr31 + Sr24—were identified. The obtained results may be used to develop strategies for breeding rust-resistant cultivars.

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