Parasitization of Bipolaris sorokiniana Sacc. Shoem. in the organ system of spring wheat varieties in the northern forest-steppe of Priobye region

Abstract

The work aimed was to identify the effect of varieties on the parasitic activity of Bipolaris sorokiniana Sacc. Shoem. in the system of underground and aboveground organs of spring wheat. The research was carried out in 2020-2021 in the northern forest-steppe of Priobye region. The tasks of the study were to investigate the development of root rot and the etiology of the disease on the underground organs of a number of spring wheat varieties of different geographical origin; determine the role of varieties in the manifestation of dark brown leaf spot and black germ of spring wheat grain; establish the presence or absence of relationships between forms of helminthosporium; identify the effect of varieties on the intensity of reproduction B. Sorokiniana on root leaves and the number of conidia of the phytopathogen in the rhizosphere soil The authors used a collection of 15 varieties of spring wheat. The study did not identify any varieties whose underground organs showed resistance to fusarium-helminthosporium rot. Root rot development averaged over the organs to reach 3.8 units of Economic Threshold of Harmfulness (ETH) in 2020, and in 2021 - 4.4 units of ETH. The effect of the “variety” factor on the incidence of root rot in spring wheat was 31.8% and the “year” factor 30.3%. The authors presented the etiology of root rot of spring wheat cultivars by Bipolaris sorokiniana Sacc. Shoem. and fungi of the genus Fusarium Link. The ratio of phytopathogenes on underground organs was determined by conditions of the year and phytosanitary state of soil; the ratio varied from 1:1 to 11:1 with predominance of fungi of genus Fusarium. The prevalence of brown spot disease reached 1.9 units to 5 units ETH in the lactic maturity phase of the cultivars. The correlation coefficient between the development of root rot and the prevalence of dark brown spot was 0.526±251 and was statistically reliable. Variety differences in the prevalence of grain black spot reached 11.4 times, 3 varieties (Sibirskaya 17, Novosibirskaya 15, Ruslada) were affected at the threshold level; 4 varieties were affected to a moderate degree; 7 varieties were severely affected. Коэффициент корреляции распространенности темно-бурой пятнистости и черноты зародыша составил 0,521±232 и был статистически достоверным на 1%-м уровне значимости. The authors used Ward’s hierarchical clustering method to divide the plants into two groups according to the sporulation dynamics of B. sorokiniana on the root leaves of spring wheat. The first group of spring wheat was with a uniform rate. The second group were varieties of wheat with an exponential jump in sporulation intensity. The varieties Jin Chun 2 (China) and K-65834 (Tajikistan) were the most active sources of B. sorokiniana reproduction in both study years. The size of the soil population of the phytopathogen reflected the intensity