The aim of this work is to analyze the virulence and phenotypic composition of samples of the populations obtained from winter wheat varieties from different breeding centers of the North Caucasus region. Population studies in the pathosystem «Wheat – leaf rust pathogen» are one of the necessary elements in the environmentally friendly cultivation of wheat and a decision on the rotation of varieties. Infectious material was obtained in 2022 on Kashchesky (Grom, Paphos and En Cephei varieties) and Caucasian (Hit variety) State variety-testing areas. To study the virulence of populations used a set of 43 varieties and near isogenic lines with known Lr-resistance genes. Fifty-three monopusular isolates of the fungus were isolated from four cultivars, from which 49 phenotypes were identified. Lines with genes Lr9, Lr29, Lr43, LrW were resistant to all isolates of the fungus. isolates virulent to the effective genes Lr24 (from the Hit and Paphos varieties), Lr41, Lr42 (from the Hit variety), Lr47 (from the Hit, Paphos, EN Cephei varieties) were observed. In all populations, most isolates were virulent to lines with genes Lr1, Lr3, Lr16, Lr3a, Lr11, Lr17, Lr30, Lr8, Lr14a, Lr14b, Lr21, Lr23, Lr25, Lr33, Lr38, Lr40. The most virulent of the studied populations was the population obtained from the variety Paphos, while the least virulent was the population from the variety EN Cephei. All samples of the populations have high phenotypic diversity. The greatest similarity (according to the V. Weyl and Rogers indices) in virulence was found between the populations obtained from varieties Grom and EN Cephei, while the least similarity was found between the samples of the populations from varieties Grom and EN Cephei. The presence in the samples of populations obtained on the varieties of winter wheat, virulent fungal isolates to effective Lr-genes necessitates both the study of the genetics of varieties and further monitoring of the virulence of the pathogen population.
O.A. Kudinova (Wed,) studied this question.