Monitoring of barley stonefly pathogen in the conditions of the forest-steppe of the Priobie region

The aim of research is to study the racial composition of the population of the causative agent of the disease Ustilago hordei in the forest-steppe conditions of the Priobie Region. The studies were conducted in 2009-2023 in field conditions against the infectious background of the phytopathological section of the plant gene pool laboratory SibRIPP&B - Branch of IC&G SB RAS, Novosibirsk District, Novosibirsk Region. The objects of study were seven differentiating varieties of the generally accepted Russian set (Excelsior, Himalaya, Hannchen, Lion, Nepal, Pannier, Trebi). The experiments were placed on fallow. Sowing was carried out in the first ten days of May. The accounting reaction of each variety was recorded by the maximum damage. Diseased and healthy ears were counted in the phase of full grain maturity. The degree of plant resistance was determined according to the scale of V.I. Krivchenko, where R is resistant varieties (damage up to 10 %), S is susceptible varieties (damage more than 10 %). Analysis of experimental data showed that the Novosibirsk population of U. hordei in 2009, 2010 and 2014 was represented by race 7, in 2011 and 2013 race 3 predominated in the population of the causative agent of hard smut, and in 2012 - race 2. In 2015, the racial composition changed and race 12 appeared in the population. Since 2016, the population has not been differentiated into races; the Excelsior and Hannchen varieties carrying the Ruh 2 and Ruh 1 genes have shown a susceptible reaction (for eight years). The highly resistant Himalaya variety-differentiator shows a type of reaction that does not correspond to the known key for determining races. The Pannier variety has shown stable resistance to the stone smut pathogen over all years of observation.