INTRASPECIES DIFFERENTIATION OF PYRENOPHORA TERES IN KAZAKHSTAN AND OMSK REGION OF RUSSIA
Intraspecies structure of Pyrenophora teres population in major regions of barley cultivation is for the first time characterized in Kazakhstan. The areas under barley were surveyed in 2015-2016 in 9 districts of 4 regions of Kazakhstan and adjacent Omsk Region (Russia). Eleven samples of the pathogen populations were studied. Phytopathological and molecular-genetic studies have shown that the majority of populations contain isolates of net-form and in one population mixture of two forms of barley net blotch pathogen was determined. Spot-form of the pathogen was identified in Korday district of Zhambyl Region on the winter barley Bereke 54. Method of polymerase chain reaction was used to characterize all populations on mating-type idiomorphs. P. teres f. maculatа isolates belong to only one idiomorph, MAT-2. In all studied P. teres f. teres populations significant deviations from null hypothesis of 1 : 1 ratio between mating types were absent, so we referred them to panmixing populations. Virulence of P. teres f. teres populations to the international set of barley differentials and race composition in Kazakhstan and in Omsk Region of Russia was determined. In the regions under study races 100 and 500 that are virulent respectively to one or two differentials have prevailed. Mainly, few races detected only in certain populations were highly virulent. Populations in Omsk Region were significantly different from Kazakhstan populations in race composition and in number of isolates virulent to diferentials.