Sources of fungal infection of winter wheat grain in the forest-steppe of Samara region

Relevance . Among the pathogenic microflora of cereals, seed infection occupies the most important place, in this regard, the search for any ways to reduce it is very relevant. Methods . The research was conducted at the VSRISSG — Branch of SamSC RAS on seeds of 3 varieties of winter soft wheat of 2020 harvest, selected at different stages of harvesting and post-harvest grain processing: from ears before harvesting, from the harvested crop from under the combine and after grain processing on the seed cleaning machine Petkus К-531. Seed infestation was determined according to GOST 12044-93. After identification of phytopathogenic fungi, their percentage frequency of occurrence and relative abundance were calculated. Results . Seed infestation after combine harvesting increased for all varieties on average by 9.2%, and after grain treatment on Petkus — by 6.2% compared to seeds sampled from ears. The saturation of crop rotations with cereals from 30 to 50% lead to an 8.7% decrease in the number of healthy seeds in the samples (from 37.0 to 28.3%). Seeds were most often infected by fungi causing moulds with the frequency of occurrence from 32.9 to 39.1% and relative prevalence from 40.8 to 55.2% depending on the stage of harvesting. Moreover, the content of this group of mushrooms decreased during harvesting (compared with grain from ears) by 6.2% after harvesting by a combine harvester and by 3.4% after grain processing. During combine harvesting, the frequency of occurrence of fungi Fusarium sp. and Alternaria sp. it increased by 4.7–4.8% on seeds, and after cleaning it decreased again, but it was still 1.5–2.4% higher than on seeds from ears.