The aim of the article is to study the effect of various biological agents of biofungicides on plant resistance to drought and formation of spring barley crops. Endophytic bacteria (Bacillus subtilis), rhizospheric bacteria (Pseudomonas fluorescens), actinomycetes (Streptomyces sp.), and micromycetes (Trichoderma viride) were used as bioagents of biofungicides. Preparations based on biological agents were used to treat spring barley seeds. The studies were carried out in laboratory and field conditions. In the conditions of the model artificial acute drought, it was found that seed treatment with Streptomyces sp. Stimulates the leaf and root growth, as well as increases peroxidase activity in the leaves. The maximum content of proline was during seed treatment with Pseudomonas fluorescens. An increase in the content of chlorophyll was observed when treating with Trichoderma viride seeds. In the field conditions, Pseudomonas putida and Streptomyces were more efficient by the content of proline in seedlings. In terms of the spring barley yield, seed treatment with Streptomyces sp., Pseudomonas putida and Bacillus subtilis was more efficient. Streptomyces sp., Pseudomonas putida and Bacillus subtilis are promising for increasing barley resistance to drought.

Modern crop cultivation technologies use biological products with adaptogenic and biofungicidal properties. The article studies the influence of Streptomyces sp on the growth, development, and formation of buckwheat crops. The treatment of seeds with biological products reduces field germination; however, their environmental sustainability increases. The maximum grain yield of 249.7 g/m2 was obtained when applying actinomycetes in the amount of 2.0 l per ton of seeds. The ability of the biological product to preserve the activity of nodes and shoots increased the number of inflorescences. The dynamics of biosynthesis and the fractional composition of chlorophyll in the leaves were studied. The biosynthesis of pigments was the most intensive during during seed treatment with Streptomyces sp in the amount of 1.0 to 1.5 l/t of seeds. The relative amount of chlorophyll “a” to chlorophyll “b” during the intensive development and mass flowering was relatively stable (2.5 ... 2.7). In the phase of fruit formation, in the control plants and plants treated with Rizoplan and actinomycetes (0.5 l/t), the proportion of chlorophyll b increased. In variants with a lower proportion of chlorophyll “b”, the seed productivity of plants was higher.