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

Abstract

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.