In view of climate change and the active extension of soybean cultivation in Russia, the identification of yield-limiting factors has become a relevant task. The objective of this study was to identify the climatic factors associated with the variation in soybean productivity under the contrasting eco-geographical conditions of the Krasnodar (KR) and Primorye (PR) territories of Russia. An analysis of 424 soybean varieties from the global collection of the N.I. Vavilov Institute (VIR) at experimental stations in KR and PR in 1987–2005 showed that the soybean yields were higher and time to maturity was longer in KR than in PR, while the 1000 seed weight, on average, was irrelevant to the place of cultivation. The agrometeorological regression models of the observations in 1972–2017 of varieties accepted as the standards showed that the yield in PR was positively related to the sum of the temperatures above 10 °C and negatively related to precipitation in October, while in KR it was positively related to the hydrothermal coefficient. The stability of the soybean yield and of the time to maturity were higher in PR than in KR. Under the conditions of increasing temperatures and the absence of reliable trends for precipitation, a lack of moisture becomes a significant disadvantage for soybean in KR, while in PR conditions are improving.

Background. Soybeans accessions from the VIR collection were tested in Primorsky Territory, Russia. These accessions had not been studied earlier in that area.Materials and methods. The testing was carried out at the Far East Experiment Station of VIR and involved 570 soybean accessions of various geographic origin. The work was performed according to VIR’s methodological guidelines.Results. The selected accessions were evaluated for their flowering and ripening schedule, seed yield, various seed characteristics (primary color of seed coat, seed hilum color, etc.), 1000 seed weight, plant height, the lower pod setting height, etc. The maximum seed yield (18.0–21.9 g) was registered for 4 accessions: ‘Primorskaya 1099’(k-9700), ‘Primorskaya 1102’ (k-9707) (Russia, Primorsky Territory); ‘Epps’(k-9308) and ‘Pioneer 3981’(k-9651) (USA). Their growing season lasted 121– 130 days. The earliest accessions ‘1337’ and ‘738-4’ (Sweden) had growing seasons of 81–90 days and low seed yields. The weight of 1000 seeds varied from 71 g to 250 g. Only one accession had 1000 seed weight higher than 300 g. The correlation between seed yield and growing season duration was medium (r = 0.57), and between seed yield and 1000 seed weight it was small (r = 0.13). Stem length varied from 15–30 to 111–130 cm. Accessions with the highest seed yield had stem lengths of 51–90 cm. The lower pod setting height ranged from a minimal level (< 6.1 cm) to 18.1–20.0 cm. Among the 92 accessions with high seed productivity (> 14.0 g) only 5 produced their lower pods at a height above 12 cm. Full-scale characterization of the material was published in Catalogue of the VIR Global Collection, Issue 905, 2019.Conclusion. The accomplished study helped to describe earlier untested accessions, grown under the environmental conditions important for soybean production. The accessions with the best economic characteristics can be used in breeding practice.

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