Effect of seed bacterization with antagonist strains mixtures and non-symbiotic nitrogen-fixing bacteria on diseases development and rapeseed growth indicators

The aim of the study is to investigate the possibility of using combinations of autochthonous antagonist strains and freeliving nitrogen fixers to protect rapeseed from fungal diseases and stimulate crop growth in the soil and climatic conditions of the Krasnoyarsk Region. The objects of the study were antagonist strains and nonsymbiotic nitrogenfixing strains isolated by the authors from agricultural soils of the Krasnoyarsk Region, as well as spring rape plants Brassica napus var. napus L. variety Forpost KL. Bacillus altitudinis (1 strain), Bacillus atrophaeus (8 strains), Bacillus cereus (2 strains), Bacillus megaterium (1 strain), Bacillus simplex (1 strain), Bacillus subtilis (4 strains), Peribacillus simplex (1 strain) and Bacillus sp. (4 strains) were used as antagonists. The Azomonas macrocytogenes strain and the Azotobacter chroococcum strain were used as nitrogen fixers. Field studies have shown that presowing bacterization of rapeseed with the studied strains significantly (by 1.92–2.67 times, or by 48–63 percentage points, depending on the combination of strains) reduces the prevalence of leaf spot, as well as the intensity of disease development (by 1.16–3.10 times, depending on the combination of strains and the phase of registration), surpassing the effectiveness of treatment with the chemical preparation Celeste Top.In addition, bacterization led to an increase in the height (by 1.13–1.20 times depending on the combination of strains) and weight of plants (by 2.25–5.60 times depending on the combination of strains) at the end of the growing season, also significantly surpassing the positive effect of the drug Celeste Top. In general, for the variants, bacterization with nitrogen fixers showed the maximum effect both in terms of reducing the prevalence and intensity of leaf spot development, and in terms of improving the growth indicators of rapeseed.