The effect of biopreparations of nodules bacteria with carmoisine on the formation and functioning of the soybean – Bradyrhizobium japonicum symbiotic systems

Purpose. Investigate the formation and functioning of symbiotic systems of soybeans with nodule bacteria by ino­culation of seeds with biological products based on fungicide-resistant strains of Bradyrhizobium japonicum PC07 and B78 with different rates of synthetic carmoisine colorant. Methods. Physiological, microbiological, gas chromatography, statistical. Results. It was found that as a result of inoculation of soybean [Glycine max (L.) Merr] variety ‘Almaz’ with microbial preparations based on B. japonicum PC07 and B78, with the addition of carmoisine (0.25 and 0.5 g per 200 g of the preparation), the amount and the weight of nodules formed on the roots during the growing season were at the level of the control plants or exceeded them. The greatest difference in indicators of quantity and weight of root nodules between plants of control and experimental variants is noted in a phase of full flowering at inoculation by both strains of rhizobia and addition to biological products of various norms of dye. Analysis of nitrogen-fixing activity (NFA) of the formed symbiotic systems showed the absence of a negative effect of the synthetic colorant on its level. When inoculated with soybean seeds B. japonicum PC07 in the phase of three true leaves, NFA was higher by 15.6–25.9% and in the budding-beginning of flowering stage by 7.4–29.5% compared with control plants with the addition of 0.25 and 0.5 g of carmoisine, respectively. Against the background of bacterization of soybean seeds by strain B78 before the phase of full flowering of plants the level of N2 assimilation by adding 0.25 g of carmoisine to the vermiculite preparation was at the level of the control plants. During the period of full flowering, this figure exceeded the indicators of control plants by 7.6 and 18.8% with the introduction of 0.25 and 0.5 g of the colorant. Conclusions. Carmoisine can be applied in the further study of the effectiveness of its use as a dye identifier for controlling the uniformity of marking of loose bacterial preparations on seeds by adding 0.25 and 0.5 g per 200 g of a biopreparation, since this did not show a negative impact on the formation and functioning of the soybean – Bradyrhizobium japonicum symbiotic systems.