The determination of drought-resistant oat varieties is based on the selection of identification indicators and the creation of a comprehensive assessment system that effectively identifies the most promising genotypes for breeding work. During three-year model experiments, 40 varieties of oats of Russian breeding were studied by measuring morphophysiological indicators and calculating the corresponding indices under stress caused by soil drought during tillering and flowering. The research was carried out in an unheated summer-type greenhouse located on the territory of the Research Institute of Agriculture of the Northern Trans-Urals. As a control, the same varieties that grew with regular watering and did not experience moisture deficiency were used. Plant height and crop structure elements were studied. The values of the protein content in the leaves, the chlorophyll index, the relative water content in the leaves and the membrane stability index were determined. It is established that the use of each indicator separately as a criterion of drought resistance does not make it possible to fully assess the drought resistance of oats. Assessment of genotypes by indices of susceptibility to drought (DSI) and tolerance to it (DTI) allows us to identify groups of drought-resistant varieties of oats and assess the degree of influence of soil drought on the elements of the crop structure. In the course of research, it was found that the varieties Privet, Peredovik, Sig, Faust, Novosibirsk 5, Barguzin, Assol are resistant to soil droughts during tillering and flowering. Their DSI was less than 0.83 and 0.78 units. accordingly. Such varieties as CROSS, Vilensky and Horizont also had high resistance to drought during tillering. The drought in the later period led to very severe stress, which negatively affected their productivity. The group of genotypes most susceptible to drought was: Dedal, Narymsky 943, Pesec, Lgovsky, Tigrovy, Express, Tayoschnik, Bulany, Borec and Desant. Their drought susceptibility index was more than 1.2 units.
