Relevance. Vegetable soybean is a special variety with high added value, consumed fresh and harvested at the stage technical ripeness (R6). Accession-A is one of the promising vegetable soybean materials, studied and identified as a result of work that was carried out jointly with the Federal Scientific Vegetable Center in the Moscow Region (FSVC) and the Agrobiotechnology Department of the Agricultural Technological Institute (ATI) of the RUDN University named after Patrice Lumumba. The use of microorganisms to promote atmospheric nitrogen fixation is a common practice in soybean production.Methodology. The purpose of this study was to evaluate the effect of two microbiological preparations based on Sinorhizobium fredii and Bradyrhizobium jaроniсum in order to identify which microbiological preparation gives the best results in terms of morphological indicators and vegetable soybean yield under the conditions region of the Non-Chernozem zone of the Russian Federation. The object of the study was accession-A of vegetable soybean. Two types of treatment were carried out: B1 – treatment with a preparation with Bradyrhizobium jaronicum (1 l/t of seeds), B2 – treatment with a preparation with Sinorhizobium fredii (1 l/t of seeds). Control without treatment (K).Results. According to statistical analysis of biometric indicators, it was found that treatment with S. fredii (B2) had the highest average values for indicators of stem diameter (11.50 mm), lower pod attachment height (11.19 cm), number of branches (3.40 pcs.) and the number of productive nodes (27.48 pcs.). Preparation B2 improved the structure of the crop, influencing the obtainment of the highest indicators of plant weight (30.47 g), seed weight per plant (15.33 g), weight of 1000 seeds (171.25 g), number of seeds per plant (98.50 pcs.), number of seeds in a bean (2.89 pcs.) and seed yield (3.11 t/ha). The use of microbiological preparations based on B. japonicum and S. fredii gave better results compared to the control treatment.

Plasmodiophora brassicae Wor. is the one of the causative agent of disease of the family of Brassicaceae, that results in decrease of white head cabbage yield up to 10-60%. The aim of the work was the study of genetic variability of doubled haploid lines of white head cabbage obtained by the isolated microspore culture in vitro aimed at selection of the lines resistant to P. Brassicae and development of resistant hybrids. The doubled haploid lines of white head cabbage were evaluated for resistance to Plasmodiophora brassicae using the method of inoculation of seedlings by pathogen in the control condition of the chamber room. As a result of assessment, the high disease distribution among doubled haploid lines was found (25- 100%), but disease development was not higher than 68%. The score of infestation was 0.5-3.3, that was comparable with the standard (3.5). The plants of the lines 3-3-3 did not exhibit any symptoms of disease that can indicate of efficiency of its gene resistance or pathogen heterogeneity. The lines with high resistance to P. brassicae were used as a parental lines for development of F1 hybrids. Using the top-crossing method the forty-two hybrid combinations were developed based on self-incompatibility. These hybrid combinations were analyzed for clubroot resistance in the field conditions on an artificial infectious background in Moscow region. Based on the data of two-year experiments, all tested hybrid combinations were divided into the groups of relatively tolerant (52.4%) and susceptible (45.2%) genotypes. Only one hybrid combination developed with line 3-3-3 has proved to be tolerant. The score of infestation of hybrid combinations varied from 0 to 1.8. The score of infestation of the standard was 2.5. The disease distribution reached 80% but disease development varied from 0 to 25%.