Biological Rationale for the Bacillus Velezensis New Natural Strain’ Use to Increase the Yield and Reduce the Soft Wheat Diseases Development Intensity

In order to develop new biopreparations, the influence of the Bacillus velezensis new natural strain on the soft wheat productivity and resistance to helminthosporiosis root rot, rust species, powdery mildew and septoria-pyrenophorous spotting was studied. When the pre–sowing wheat seeds treatment with the strain was carried out, a significant increase in most morphometric productivity indicators, including those characterizing the spike structure, in comparison with the action of the biopreparation “Naturost” was revealed (at P > 0.05–71.4%; at P < 0.05– 33.0%). Seeds inoculation with Bacillus velezensis led to a statistically reliable increase in the spike length (by 8.2%), the spike weight (by 20.5%), the grains number (by 14.5%) and the grains weight (by 16.1%) per spikelet of the spike, the grains number per spike (by 19.4%), the grains weight per the spike (by 18.4%), biological (by 49.9%) and potential (by 45.4%) yield, while the plant roots weight increased by 52.1% compared to the control. In this experimental variant, an increase in plant affection by leaf-stem diseases: yellow rust, brown rust, powdery mildew (accounted by the area of the spot with a plaque), which are obligate parasites and live relying exclusively on the nutrients of the living host plant, was revealed. The maximum decrease in the root rot development by 70.4% was recorded in the variant when spraying plants with Bacillus velezensis bacterial culture.