Features of internodes lengths storeyed variability at soybean forms with various reaction to day length

Reaction of different maturity group soybean varieties to change of day length from 12 up to 18.5 h is studied on the basis of internodes lengths storied variability. It is established, that adaptability of soybean genotype to geographical latitude and optimal on day length zones of variety cultivation are possible to define on the basis of asymmetry factors and completeness of vegetative growth. Sources of the lowered photoperiodic sensitivity are allocated: early-maturing variety Aldana and late-maturing variety Williams, suitable for use in breeding programs on development of soybean varieties with the lowered sensitivity to the day's length.