Microbiota of spring wheat seeds grown within the contrasting agroclimatic conditions of the Tyumen region

Relevance . Pathogenic microbiota of seed grain can cause death of seedlings, root rot, weakening of plants and a decrease in yield. Monitoring of seed grains pathogens infection rate is always relevant because the composition of the microbiota is dynamic due to the influence of natural and anthropogenic factors. Methods . Phytopathological analysis of spring wheat seeds grown at the state variety testing sites of the Tyumen region was carried out in contrasting years: cool and excessively moist in July 2015 and hot with moderate rainfall in 2016. We used the “wet chamber” method. 144 samples were analyzed. Results . Fungus of the genus Alternaria were the most abundant representatives of the grain microbial community. Average infection rate of seed samples with fungi Alternaria spp. was 49.5%. No differences were found by year of the study. In 2015 compared to 2016, higher prevalence of fungus of the genus Fusarium (4.8% vs. 1.6%) and bacteria (5.7% vs. 0.7%) was observed in the seed material. The maximum indicators of Fusarium infestation were observed in samples from Nizhnetavda variety testing site located in the subtaiga zone – up to 30% (variety Ikar). In 2016 compared to 2015, higher infection of seed material with helminthosporiose (7.1% vs. 2.6%) and mold fungi (2.3% vs. 0.2%) was observed. The prevalence of Bipolaris sorokiniana fungi was the highest in wheat samples grown in the northern forest-steppe zone, especially samples from the Yalutorovsky variety testing site — the limit value was 27% (variety SKENT-3). Harmfulness fungus of the genus Alternaria was significantly lower compared to other key representatives of grain microbiota. The average score of seedling damage was 1.4 vs. 2.2–2.6, seed germination indices — 94.1% vs. 53.2–67.4%.