A model of early maturing soybean cultivar for the Southern-European part of Russia
A model of a cultivar was developed based on comparative studying of five early soybean cultivars included into the State Variety Register of breeding achievements of the Russian Federation in 1994-2007 and widely produced in the Southern-European part of Russia. The main traits indicators for soybean cultivar were determined to obtain seed yields higher 4.0 t per ha in the optimal conditions for plants growth and development. They are: the plant height within 90-115 cm for cultivars with vegetative period 100-110 days, height of the low pod attachment - 13-15 cm. Branches amount should be no more than two ones per a plant in optimal plant population; this allows the plants to realize seed productivity mostly on a general stem, its share in yield must be within 50-70%. It is determined the more amount of abortive seeds in the upper plant part and it is decreased logically toward the lower plant part. As a result pods share in low and middle plant part must be 75-85% of total pods amount, herewith seed formation productivity must make 85-90%. Cultivation of the semi-determinant cultivars with shortened period of seedlings-flowering (28-35 days) and prolonged flowering period (37-45 days) is preferable in conditions with insufficient moistening and irregular precipitations during vegetative period. Herewith, the first mentioned period must be characterized with lowered speed of plants growth (2.2-3.3 g per sq. m per day), and the second one - with temperate (8-13 g per sq. m per day). The highly productive plants must have an effective redistribution of plastic substances both between vegetative organs and generative part (harvesting index 39-42%) and in pods (index of microdistribution - 70-72%). Biochemical traits of seeds are recommended to control on a result achieved by breeding: protein content - 40-43%, oil content - 21-23%, trypsin inhibitory activity - 19-23%.