Abstract
This article presents the cultural and morphological characteristics of actinomycetes isolated from cow dung, as well as the results of their genotyping and assessment of growth-stimulating properties in relation to the seedlings of spring wheat. In vitro inoculation of seeds was conducted with strain Streptomyces macrosporeus st.№.32, Streptomyces albogriseolus st.№37, Streptomyces pratensisst.№24, Streptomyces griseorubens st.№34, and Streptomyces flavofuscus st.№38. As a result, a high efficiency of these microorganisms in stimulating plant growth was established. Treatment of seeds with cultural filtrates of strains Str. Albogriseolus st.№37 and Str. Flavofuscus st.№38 ensured 100% seed germination, indicating the high biological effectiveness of these strains. Some strains effectively stimulated the development of the root system, while others increased seed germination or demonstrated the ability to synthesize cytokinins. Thus, treatment of wheat seeds with a suspension of strains Str. Pratensis st.№24, Str. Griseorubens st.№34, Str. albogriseolus st.№37, and Str. flavofuscus st.№38 led to a significant increase in germination. The maximum increase in root length was 1.8 times, while the length of seedlings increased 3.3 times compared to the control, indicating the feasibility of using these strains in agronomy. The most pronounced influence on seedling development was exerted by strains Str. flavofuscus st.№38, Str. albogriseolus st.№37, and Str. griseorubens st.№34, with the maximum seedling length achieved when inoculated with strain Str. flavofuscus st.№38, indicating its high growth-stimulating activity. For stimulating root growth, the optimal strains were Str. albogriseolus st.№37 and Str. flavofuscus st.№38, which ensured an increase in root length by up to 1.7 times compared to the control. In this context, the use of Streptomyces sp. strains as biopreparations represents a promising direction for environmentally friendly agriculture.