Features of yield formation and elements of its structure in soybean plants in the southern forest-steppe of Western Siberia

The results of the study carried out in 2016-2018 on varieties of common cultural soybean on chernozem soils under the conditions of the southern forest-steppe zone of Western Siberia are presented. The aim of the research is to identify the potential of new high-productive fast-growing varieties of soybean varieties of local breeding recommended for cultivation under the forest-steppe conditions of Western Siberia. The experiments were carried out in four-field grain crop rotation at the Omsk Agrarian Scientific Center with winter triticale as a forecrop. Four soybean varieties zoned in the steppe and forest-steppe zones of Western Siberia were included in the trial scheme: Zolotistaya, Eldorado, Cheremshanka, and the control sample Sibiryachka. On average, over three years all varieties showed themselves as average with an optimal growing period for the region ranging from 98 to 109 days. According to the number of seeds per plant, the variety Eldorado distinguished itself with 42.2 pcs. The highest thousand kernel weight was observed in the variety Sibiryachka (183.5 g), the lowest one in the variety Eldorado (154.0 g). The most productive plants were noted in the Cheremshanka and Eldorado varieties with 6.6 and 6.5 g/plant, respectively, outperforming the control sample by 8%. A strong positive association between the plant productivity and the number of productive nodes (r = 0.91), beans (r = 0.87) and seeds on the plant (r = 0.89) was established; the association with the thousand kernel weight is also positive but of average value (r = 0.60). The yield of soybean varieties during the years of research depended on the number of productive nodes (r = 0.73) and beans on the plant (r = 0.84), seed weights per plant (r = 0.64) and stem length (r = 0.69). The yield of the Cheremshanka variety was significantly higher than the control sample: 0.45 t/ha in 2016 and 0.78 t/ha in 2018 (3.44 and 2.90 t/ha, respectively, for the Sibiryachka control sample). In 2017, all varieties in the experiment were high-yielding - with the maximum value in the Cheremshanka variety - with a value of 3.93 t/ha (3.62 t/ha in the Sibiryachka control sample, LSD05 = 0.47). It has been proved that the potential of soybean under the conditions of the Omsk Region is significantly higher than the results of its cultivation in progress.