The research study was focused on analyzing the virulence and phenotypic composition of P. triticina population sampled from the winter wheat varieties in different selective breeding centers in the North Caucasus region to assess crop cultivation biosafety and requirements on variety replacement. The infectious pathogen materials were collected on the Kushchevsky (Grom, Pafos and EN Tsefei varieties) and Caucasian (Khit variety) state variety-test plots in 2022. To study the virulence of P. triticina populations, the Thatcher set containing in total 43 varieties and near-isogenic lines carrying the well-known Lr-resistance genes was used. Overall, 53 monouredinial fungal isolates represented by 49 phenotypes were isolated. Lines containing genes Lr9, Lr29, Lr43, and LrW were resistant to all the isolates of the fungus. P. triticina isolates virulent to the effective genes Lr24 (from the Hit and Pafos varieties), Lr41, Lr42 (from the Khit variety), and Lr47 (from the Khit, Pafos, EN Tsefei varieties) were recorded. The most studied isolates were virulent to the lines carrying genes Lr1, Lr3, Lr16, Lr3ka, Lr11, Lr17, Lr30, LrB, Lr14a, Lr14b, Lr21, Lr23, Lr25, Lr33, Lr38, and Lr40. The isolates derived from the Pafos variety were characterized by the highest frequency of virulence alleles in the study, while the lowest virulence-allele frequency was recorded in the EN Tsefei variety. All the samples of the pathogen populations were different in high phenotypic diversity. In accordance with the Nei’s gene diversity index, the P. triticina sampled from the Khit and EN Tsefei varieties was characterized by the most significant similarities in virulence, while the moderate similarities in virulence were revealed in the samples from the Grom and EN Tsefei varieties. The fungal isolates virulent to effective genes Lr, existing in the P. priticina populations sampled from the winter wheat varieties, indicate the key reason for studying genetics of these varieties to monitor subsequently the pathogen population virulence.
Kudinova et al. (Mon,) studied this question.