THE INFLUENCE OF PENICILLIUM FUNGI ISOLATED FROM SOYBEAN ROOTS ON THE SYMBIOTIC SYSTEM “GLYCINE MAX – BRADYRHIZOBIUM JAPONICUM” AND CROP PRODUCTIVITY

Abstract

Objective. Identify new strains of Penicillium endophytic fungi by morphological and cultural properties, study their influence on the symbiotic system “Glycine max – Bradyrhizobium japonicum” and soybean productivity. Methods. Microbiological (cultivation of endophytic fungi, preparation of spore suspensions, determination of spore titre in suspensions, light microscopy), gas chromatographic (determination of nitrogenase activity of soybean nodules), vegetation and field small-plot experiments (study of the effect of endophytic fungi on symbiotic and morphometric parameters of soybean plants and crop yield when growing on sod-podzolic soil), statistical. Results. New strains of Penicillium endophytic fungi are attributed to the species P. funiculosum Thom, P. variabile Sopp, P. glauco-lanosum Chalabuda, and P. steckii Zaleski based on their morphological and cultural characteristics. Under the conditions of the vegetation experiment, the positive influence of the studied strains on the symbiotic parameters of soybeans was shown. A tendency towards an increase in the number of nodules versus the control in all variants, an increase in the mass of nodules in the variants when soybean seeds were treated with spores of P. variabile 20173 and P. funiculosum 20312 by 28.4 % and 36.4 %, respectively, an increase in the nitrogenase activity of nodules by 29.8–38.5 % in variants with the use of P. stekii 2204, P. glauco-lanosum 20401, P. variabile 20173 was registered. The results of the study of soybean symbiotic parameters under the conditions of the field experiment generally confirmed the corresponding data of the vegetation experiment. Inoculation of soybean seeds with spores of Penicillium endophytic fungi contributed to an increase of the morphometric parameters of plants, namely: height — by 4.6–6.2 cm in all variants of the experiment, above-ground mass of dried plants — by 11.1–19.0 % when treated with P. stekii 2204, P. glauco-lanosum 20401, P. variabile 20173, mass of dry roots — by 13.2 % and 18.4 % with P. funiculosum 20312 and P. variabile 20173. The results of the field experiment proved the positive influence of new strains of endophytic fungi on soybean yield: when soybean seeds were inoculated with P. variabile 20173, P. funiculosum 20312 and P. stekii 2204, the increase in grain productivity was on average from 11.8 % to 17.3 %. The weight of 1000 grains increased by 3.8–5.1 % in variants using P. variabile 20173, P. glauco-lanosum 20401, P. stekii 2204. Conclusion. Penicillium endophytic fungi, which belong to the species P. funiculosum, P. variabile, P. glauco-lanosum and P. stekii, were isolated from the tissues of soybean roots. It was found that Penicillium endophytic fungi have a positive influence on the functioning of the symbiotic system “Glycine max – Bradyrhizobium japonicum” and soybean yield.