Biology of soybean: possibilities to optimize the separate production processes

To enlarge seed productivity of soybean it is necessary to prolong studying of this crop biology and its biological features. Such features are: photoperiodic reactions, duration and intensiveness of organogenesis stages, effectiveness of symbiotic nitrogen fixing. The cultivars of Amur breeding were studied: MK 1, Amurskaya 310, Yantarnaya, VNIIS 1, Smena (developed and partially used in 1975-2005). The relatively high productivity of photosynthesis was recorded at cultivars: МК 1 (5.2 g per cm2), VNIIS 1 (4.78 g per cm2), Yantarnaya (3.46 g per cm2). The maximal meaning was noted at wild soybean (7.10 g per cm2). In some cases there were observed discrepancies between level of vegetative mass growth and plant yield. It is explained by features of a cultivar on redistribution of plastic substances between plant organs in the different phases of its development. Number of assimilates per a bean during the phase of pods formation varies from 0.64 to 10.0 mg. A phenomenon of flowers and beans abortion is observed at the second half of vegetative period. This is caused considerably by a deficit of nutrients. Number of buds forming pods was 39, 32, 31% (of their total number), respectively, for cultivars Smena, VNIIS 1, Amurskaya 310. This trait of wild soybean exceeds 67%. Activity of symbiotic system in the first half of vegetative period (quantity and weight of tubercles) of cultivars MK 1 and Smena (which are differed with vegetative period duration more than seven days) was almost equal. In studying soils a high level of correspondence (determinacy) was noted in system cultivar-strain. Expenses for tubercles formation are from 1.8 to 2.3% of aboveground mass in phase of pods ripening. ‘Uneconomic’ utilization of assimilates aggravated by abortion is observed during the some stages of organogenesis and development phases.