The soybean development goal in Korea has changed over time, but the pattern of genetic diversity in modern varieties has not yet been well characterized. In this study, 20 simple sequence repeat (SSR) markers are shown to generate a total of 344 alleles, where the number of alleles ranges from 7 to 29, with an average of 17.2 per locus, and the polymorphism informative content (PIC) values range from 0.6799 to 0.9318, with an average of 0.8675. Five different clusters are classified using the unweighted pair group mean arithmetic (UPGMA) method. The genetic distance between clusters I and V (0.3382) is the farthest, and that between clusters III and IV (0.0819) is the closest. The genetic distance between all pairings of groups, according to the time period of their release, is lowest (0.1909) between varieties developed in the 1990s and those from 2000 onward, and highest (0.5731) between varieties developed in the 1980s and those from 2000 onward. Model-based structure analysis revealed the presence of three sub-populations and 17 admixtures in the Korean soybean varieties. All 172 Korean soybean varieties were tested for discrimination using six SSR markers. The numbers of varieties that were clustered in each step are as follows: 7 (4.1%) in step 1 (Sat_076), 73 (42.4%) in step 2 (Sat_417), 69 (40.1%) in step 3 (Sat_043), 13 (7.6%) in step 4 (Satt197), 8 (4.6%) in step 5 (Satt434), and 2 (1.2%) in step 6 (Satt179). These results, based on the analysis of genetic resources, can contribute to the creation of a core collection for soybean conservation and breeding, as well as to the development of future varieties with useful traits.

This study was carried out to investigate the variations in protein and isoflavone contents of 300 soybean germplasms introduced from domestic and foreign countries and to compare their contents in terms of size, colour and country of origin. The protein content ranged from 28.7 g 100 g⁻¹ to 44.5 g 100 g⁻¹, with an average of 39.0 g 100 g⁻¹. In a comparison of protein according to country of origin, the highest content was seen in soybeans from Korea (39.7 g 100 g⁻¹), followed by North Korea (39.2 g 100 g⁻¹), China (39.0 g 100 g⁻¹), Japan (38.8 g 100 g⁻¹), the USA (38.0 g 100 g⁻¹) and Russia (37.2 g 100 g⁻¹). The total isoflavone content ranged from 207.0 µg g⁻¹ to 3561.8 µg g⁻¹, with an average of 888.8 µg g⁻¹. In the comparison of isoflavone content according to country, the highest average content was shown in soybeans from Japan (951.3 µg g⁻¹), followed by the USA (918.7 µg g⁻¹), Korea (902.2 µg g⁻¹), North Korea (870.0 µg g⁻¹) and Russia (710.6 µg g⁻¹). Daidzein, glycitein and genistein isoflavone contents were positively correlated, while total isoflavone and protein showed a low negative correlation.

Xiang-Min Piao, Seong Yel Choi, Young Seok Jang, Yoon-Sup So, Jong-Wook Chung, Sok-Young Lee, Jae-Hyun Jong, Hong Sig Kim. PBB 2014;2:35-47. http://dx.doi.org/

Xiangmin Piao, Seong Yel Choi, Young Ho Kim, Yong Hwa Lee, Kwang Soo Kim, Young Seok Jang, Yoon-Sup So, and Hong Sig Kim. Plant Breeding and Biotechnology 2013;1:91-101. https://doi.org/10.9787/PBB.2013.1.1.091

Hyun Myung Kim, Eun Kyu Jang, Byeong Sam Gwak, Tae Young Hwang, Geon Sig Yun, Se Gu Hwang, Heon Sang Jeong, and Hong Sig Kim. Korean J. Breed. Sci. 2018;50:50-60. https://doi.org/10.9787/KJBS.2018.50.1.50