INJURIOUSNESS OF THE BARLEY SMUT AGENT UNDER CONDITIONS OF THE FOREST-STEPPE OF THE OB REGION
A field experiment to identify the injuriousness of Ustilago hordei (direct and concealed losses) was founded against an isolated infectious background of the Siberian Research Institute of Plant Growing and Breeding in 2009-2011. Nine barley varieties with different resistant to the pathogen were used: practically resistant (Agul 2, Bagan, Petr); weakly susceptible (Biom, Odessky 115, Omsky 88); susceptible (Noktyurn, Omsky 95, Chelyabinets 1). The seeds were inoculated by the population of barley smut under laboratory conditions according to the methodology of VIR. The same varieties, uninfected by barley smut, were used as a control. Concealed losses were calculated according to the Chumakov's method. Ustilago hordei influenced the growth and development of barley. The average number of sprouted plants was 1.2 times higher in the case of sowing of health seeds than of infected ones. It was observed for all sowing dates. In the affected plants the height decreased (by 3.3 cm on average for all varieties over the years of the research) and the number of stems reduced. On average over the years of the research, a decrease in the yield was recorded as a result of plant affection with barley smut. The greatest decreased in productivity was in varieties with practical resistance. The yield losses in this group were from 9 to 23%. Biom and Omsky 88 varieties from the group of weakly susceptible varieties were tolerant to the pathogen, concealed losses were 0%. Susceptible varieties had both direct and concealed losses. The highest percentage of total losses (obvious and hidden) was registered in Noktyurn variety (23%). In Omsky 95 variety obvious losses were 8.4%, concealed losses were 8.2%. Chelyabinets 1 variety did not have concealed losses, but obvious losses were 12.9%.