Occurrence of spackled yellows agent of winter wheat. Pyrenophora triticirepentis in the Republic of Belarus and selection of sources of increased resistance to pathogen

 From the point of view of economic efficiency and environmental impact in the country, the most profitable way to fight the Pyrenophora tritici-repentis agent is creation of highly resistant varieties, which is relevant and important in increasing crop gross yield and ensuring food security in the country. Pyrenophorosis (spackled yellows) is a relatively new disease of winter wheat in the Republic of Belarus. No aimed researches for occurrence monitoring, predominant racial composition, biological peculiarities of pathogen, search for resistance sources in the country were carried out, which collectively determined the relevance of the research topic. The paper presents results of study of spackled yellows agent occurrence of winter wheat leaves in the Republic of Belarus (2016-2018), as well as racial composition. Route examinations revealed disease in all the areas of the country, which indicates a potentially high risk of this disease. Analysis of racial composition showed that race No. 8 of spackled yellows pathogen prevails on the territory of the Republic of Belarus, No. 1 and No. 6 races occur insignificantly. Laboratory experiments were conducted to identify the best artificial nutrient medium, exposure at low temperatures to stimulate the pathogen sporulation in order to obtain high-quality inoculum necessary for artificial infection. Against background of artificial infection, the world and Belarusian collections of winter wheat were analyzed for resistance to pyrenophorosis Pyrenophora tritici-repentis (283 and 47 pieces, respectively). For three years of estimation, 28 variety samples of winter wheat with increased resistance to the disease were allocated from the world collection and 19 variety samples - from the Belarusian collection. It was determined that the greatest number of resistant samples to spackled yellows of winter wheat leaves come from Europe and Belarus in particular. 

Acknowledgments. Research was conducted as part of the state program of scientific research for 2016–2020 “Quality and efficiency of agro-industrial production”, subprogram “Agriculture and Selection”, task 6.13 “Study of species diversity of winter wheat of various ecological and geographical origin and identification of sources of resistance to the main pathogens”. 

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