Genetic sources of resistance bread winter wheat to leaf (brown) rust and their value in juvenile stage of growing

Actuality of the topic. With the growth of prices for fungicides, the ecological crisis of the biosphere, the absence of a wide range of donors, and with the constant variability of the pathogen, resistance of bread winter wheat plants is lost, therefore, it is important to search for new effective sources of resistance and involve them in breeding work for resistance to leaf rust. The purpose of the research is to compare genotypes of different ecological and geographical origin and to determine the best genetic sources of resistance to brown rust for their effective use in breeding. Methods. The experiment was carried out in laboratory conditions; Bread winter wheat samples were contaminated with leaf (brown) rust spores in the juvenile stage of growing. Research results. Among the four analyzed genetic sources of resistance of different ecological and geographical origins, the best were the representative genotypes from other breeding institutions of Ukraine. According to the average indicator of resistance, their average level of resistance was at the level of 6.5 points on a 9-point scale, and genotypes of Western European origin – 5.2 points, genotypes of selection from SGI–NCSS and CIMMYT-ICARDA - Turkey had the worst score – 4.6 and 3.4 points. Summary. The fact that bread winter wheat genotypes from other breeding institutions of Ukraine and Western European origin are the best can be explained by the formation of these genotypes in optimal conditions for the development of leaf (brown) rust, which served as a natural infectious background for selection for resistance to this trait. However, among genetic sources with low resistance, there are samples with increased resistance, which, in combination with other adaptive traits, can be successfully used in the selection of bread winter wheat for resistance to leaf (brown) rust for the south of Ukraine. Keywords: bread winter wheat, leaf (brown) rust, sources of resistance, genotypes-representatives, resistance