Pathogen racial composition of Pyrenophora tritici-repentis in the south regions of Kazakhstan in 2018 year

Abstract

In this article are considered about tan spot of leaves caused by the hemibiotroph fungus Pyrenophora tritici-repentis Drechsler - a harmful wheat disease that has spread almost all over Kazakhstan. The interaction of the “wheat-pathogen” pathosystem becomes one of the discussing issues and piques the interest among the phytopothologists, genetics and breeders around the world. A population study of phytopathogens is necessary to substantiate strategies for the genetic protection of wheat, which makes it possible to characterize the dynamics of the racial composition of pathogens, to assess the influence of cultivated wheat sorts on the variability of the fungus population and the efficiency of resistance genes in host plants. The aim of this study is to determine the racial composition of tan spot populations collected from commercial winter wheat varieties of cultivated in the Almaty, Jambyl and Turkestan regions. The study used 135 monoconidial isolates of the fungus isolated from samples of populations collected in the south and southeast of the country in 2018. Pathogen races were identified using Glenlea, 6B365 and 6B662, Рtr ToxA, Ptr ToxB and Ptr ToxC. Races 3 and 8 prevailed in the surveyed regions, as well as in individual populations. In the isolates tested, the ToxB gene was not identified, and all the populations studied all consisted of isolates with the ToxA gene. Keywords: Pyrenophora tritici-repentis, wheat, population, isolate, race, ToxA, ToxB, necrosis.