| Summary: | Hybridization of resistant and unstable samples is the main method of producing resistant accession of cultivated plants. At the same time, a number of additional factors are important: the direction of crosses, the morphology of plants, the year and the spe-cific place of assessment of resistance/susceptibility. A cultivar of spring bread wheat Triticum aestivum L. Novosibirskaya 61 (breeding SRIPPB), resistant to brown rust and powdery mildew, and three susceptible samples, cultivar Skala, accession Khakasskaya (CIMMYT 2167) and spelt accession к-53660 from Tajikistan were crossed. In most variant, the F1 plants were resistant, but in the variant where Khakasskaya was used as the mother form, differences were observed: out of 21 plants, 17 plants were F1 resistant, 4 plants were sus-ceptible. The analysis of segregation was carried out to F2 generation separately in progeny from resistant and susceptible plants of F1. Segregation analysis showed that resistance dominated the offspring from resistant plants of the F1. In the progeny from susceptible F1plants most plants were susceptible to both diseases. The effect of leaf pubescence from the accession Khakasskaya on the degree of damage was also evaluated. This result indicates that the accession Khakasskaya is heterogeneous in cytoplasmic determinants. Pubes-cent plants in the F2 generation more affected by powdery mildew. Resistance to brown rust was not affected by leaf pubescence. The pubescence segregation corresponded to a digenic ratio of 13:3 for dominant epistasis. There was no significant correlation between resistant to powdery mildew and resistance brown rust. Resistance to powdery mildew and brown rust in the cultivar Novosibirskaya 61 is inherited in most cases as a dominant character.
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