Monitoring the virulence of the wheat yellow rust pathogen in Dagestan

Background. Yellow rust is a harmful disease of wheat. In the 2020s, it has dominated in the phytopathogenic complex at Dagestan Experiment Station of VIR, where an extensive collection of Triticum L. accessions is studied. An analysis of the virulence and racial composition of Puccinia striiformis West. forming on new and commercial wheat genotypes makes it possible to assess the situation with yellow rust in the regions of their cultivation. The objective was to monitor the virulence of the Dagestan population of P. striiformis in 2023 and assess the dynamics of its variability. Materials and methods. Leaves with urediniopustules of P. striiformis were collected at Dagestan Experiment Station of VIR in 2023 on 30 accessions of modern domestic winter bread wheat cultivars. The differential set included 14 nearly isogenic lines of cv. ‘Avocet’ (AvNILs) and 15 cultivars from the European and international sets. Virulence was analyzed on 10–14-day-old seedlings (second leaf phase) according to the previously described techniques. The resistance of differentiators in the phase of adult plants under high natural disease pressure was assessed. Results and conclusion. The genes Yr5, Yr10, Yr15, Yr24, and Yr26 exhibited high efficiency in the seedling and adult plant phases and are recommended for yellow rust resistance breeding. Twenty-three phenotypes (races) were identified in 2023, and only six of them were observed on two or more cultivars. Comparing the phenotypic composition in 2023 with the previous period revealed high diversity and dynamism of the Dagestan population. A total of 139 isolates were studied in 2020‒2023, and 54 phenotypes (races) were isolated. No race common for all four years of the study was identified. The Dagestan population of P. striiformis demonstrated significant temporal variability. The population in 2023 significantly differed from those in 2020–2022. This necessitates annual monitoring of the pathogen.