Early-maturing and chilling-tolerant soybean lines derived from crosses between Japanese and Polish cultivars.

Early maturity is an important trait for soybean [Glycine max (L.) Merr.] growing in Hokkaido where the growing period is restricted because of the short fall season and early snowfall. Development of an early-maturing line without decreased seed yield is difficult because of the positive correlation between days to maturity and seed yield. In this study, we developed two breeding lines, Tokei 1067 (T1067) and Toiku 251 (T251), that were derived from crosses between Japanese and Polish cultivars. T1067 and T251 had a significantly earlier maturing time than Yukihomare (YH), the standard cultivar in Hokkaido. The seed yield of T251 was similar to that of YH. Moreover, the chilling tolerance levels of the T1067 and T251 lines at the flowering stage were greater than the tolerance level of YH.