The Korean Journal of Crop Science ISSN:0252-9777(Print) 2287-8432(Online) 한국작물학회지

This study was conducted to evaluate the flowering characteristics of 22 soybean (Glycine max Merrill) varieties of North Korea and classify the flowering group by the flowering date. The flowering date and the days required for flowering with the different planting times on May 31, June 19, June 30, July 3, and July 4 were investigated at the agricultural experimental field of Korea University for three years from 2017 to 2019. The flowering date and the days for flowering of “Yeonpungkong”, an early maturing soybean cultivar of Korea, were July 18 and 48 days, respectively, at the planting time of May 31, those of “Daewonkong”, a mid-late maturing cultivar, were July 30 and 60 days, respectively. Based on the flowering dates of “Yeonpungkong” and “Daewonkong”, North Korean soybean varieties were classified into six flowering groups. Eight North Korean soybean varieties had the flowering dates earlier than “Yeonpungkong”, including “Brekkhat” classified into the early flowering group. The range of flowering date was July 2 to 15 at planting time of May 31. Twelve North Korean soybean varieties had flowering dates similar to or later than “Daewonkong”, including “Chang Dan Bac Mok” classified into the mid-late flowering group. The range of flowering date was July 24 to 30 at the planting time of May 31. For flowering response to environmental stimulus, all of the mid-late flowering varieties of North Korea responded to “photosensitive or day-length” for flowering reaction. The early flowering varieties were divided by “photosensitive” response and “temperature” response variety.