(Igor Sikorsky Kyiv Polytechnic Institute, 2023) Vorobey, N. A.; Kukol, K. P.; Kots, S. Ya.; Pukhtaievych, P. P.; Patyka, V. P.
Background. With the increase in soybean cultivation areas, inoculants are becoming increasingly sought after. They are not only compatible with the original preparations for seed treatment of soybean but also offer the possibility of applying them for several days or even months before sowing into the soil. Objective. The viability of new strains of nodule bacteria Bradyrhizobium japonicum (strain PC07 and strain B78) was investigated on the surface of soybean seeds treated with fungicides Fever and Maxim XL during the extended storage of inoculated seeds. Additionally, their ability for nitrogen fixation under symbiotic conditions was evaluated. Methods. Сultivation, serial dilution method, determination of bacterial titer of inoculants, quantification of colony forming units (CFU), gas chromatography. Results. In laboratory conditions, on the soybean seeds of Almaz and Vasylkivska varieties, the viability of the nodule bacteria B. japonicum PC07 and B78, which are more resistant to the active substances of these fungicides in pure culture, decreased. This reduction was dependent on the storage period, the fungicide used, and the strain of inoculant. One day after inoculation on the seeds without the use of fungicide, 68.6–75.4% CFU of the initial number was retained. Seeds treated with the fungicide Fever contained 36.5–38.3% CFU, and those treated with Maxim XL contained 26.2–27.0% CFU.