Variability features of the early ripeness traits of soybean vegetable and grain forms

It is shown that early biological ripeness of the soybean plant in the region of the Central Nonblack earth area with the low sum of active temperatures and short vegetation season has a significant value in agricultural production. It is not only genetically determined but also depends on the conditions of growing and weather-climatic features within the period of crop growth and development. The variability of the early ripeness traits within the interphase development periods was studied at 190 breeding lines representing the vegetable and grain forms of Russian and foreign origin, with a very early and early ripeness groups in the conditions of 55° N latitude. The duration of the vegetation period of the soybean is represented in the form of the sum of the active temperature. The earliest ripening samples of the vegetable and grain soybean are revealed with the necessary sum of the active temperatures—respectively 1838 and 1757°C in the conditions of Moscow oblast. A low variability of the duration of the vegetative, generative, and vegetation periods is specified. The interphase development periods of the vegetable and grain forms, except for the bud and flower formation periods, also has a weak variability degree, which is important to be considered in the breeding work. It is specified that the vegetable forms of the soybean are characterized by a later ripeness than the grain forms.