The soybean cultivar, ‘Saegeum’, has been developed for preparing soy-paste and tofu. The soybean cultivars ‘Daepung’ and ‘SS98207-3SSD-168’ were crossed in 2003 to obtain ‘Saegeum’. Single seed descent method was used to advance the generation from F₃ to F₅, and the plant lines with promising traits were selected from F₆ to F₇ by pedigree method. The preliminary yield (PYT) and advanced yield trials (AYT) were conducted from 2009 to 2010, and the regional yield trial (RYT) was conducted in 12 regions between 2011 and 2013. The morphological characteristics of ‘Saegeum’ were as follows: determinate plant type, white flower, tawny pubescence color, and brown pod color. Flowering and maturity dates were August 2, XXXX and October 17, XXXX, respectively. Plant height, first pod height, number of nodes, number of branches, and number of pods were 79 cm, 18 cm, 16, 2.3, and 44, respectively. The seed characteristics of ‘Saegeum’ were as follows: yellow spherical shape, yellow hilum, and the 100-seed weight was 25.4 g. ‘Saegeum’ was resistant to bacterial pustule and SMV in the field test, and its lodging resistance was mildly strong, whereas its shattering resistance was excellent. The ability of this cultivar to be processed into tofu, soybean malt, and other fermented products was comparable with that of ‘Daewonkong’. The yield of ‘Saegeum’ in the adaptable regions was 3.02 ton ha^-1. Thus, ‘Saegeum’ is adaptable to mechanized harvesting because of its high first pod height, as well as lodging and shattering resistance. (Registration number: 5929)

This study was carried out to investigate the variation of 12 isoflavone components among 172 Korean soybean varieties released from 1913 to 2013. Cluster analysis was performed to classify the varieties based on the variation of isoflavone contents. Total isoflavone contents ranged from 206.3 μg/g to 2666.2 μg/g with an average of 837.2 μg/g. By each component, malonylgenistin content ranged from 99.2 μg/g to 1149.1 μg/g with the highest average of 390.0 μg/g, and glycitein content ranged from 0.1 μg/g to 2.4 μg/g with the lowest average of 0.8 μg/g. Among composition groups, the aglycone group contents ranged from 2.2 μg/g to 33.1 μg/g with the lowest average of 10.0 μg/g, and glucoside group contents ranged from 36.9 μg/g to 801.8 μg/g with an average of 202.4 μg/g. The malonylglucoside group contents ranged from 143.6 μg/g to 1796.4 μg/g with the highest average of 599.1 μg/g and acetylglucoside group contents ranged from 3.7 μg/g to 103.9 μg/g with an average of 27.5 μg/g. Varieties with high total isoflavone content were Aga8(2666.2 μg/g), Aga4(2569.3 μg/g), and Aga9(2345.0 μg/g) in bean sprouts group. The low total isoflavone content were observed from Deawang(328.8 μg/g) in soy sauce and paste group, Hanol(599.3 μg/g) in vegetable and early maturity group and Gemjeong1(664.1 μg/g) in cooking with rice group. The first three principal component axises accounted for 89.14% of the total variation observed. Dendrogram constructed using average linkage cluster method revealed that 172 Korean soybean varieties were divided into seven groups with the average distance of 0.8 between groups. The group Ⅰ includes 57.6% of the total varieties, which was the largest group among seven groups, followed by the group Ⅱ that includes 35.5% of the total varieties. However, the other groups were small groups containing less than five varieties. In comparison among the total isoflavone contents according to groups, the highest isoflavone content was observed in group Ⅵ with an average of 2526.9 μg/g, followed by group Ⅳ(1546.6 μg/g) and group Ⅴ(1503.5 μg/g). The others were found to contain low isoflavone content.

This study was carried out to evaluate the oil contents and fatty acid compositions of 379 soybean germplasm accessions which is composed of 128 Korean, 214 Chinese and 37 USA accessions, and to select useful resources for the development of high oil content and quality fatty acid varieties in soybean. Korean and Chinese germplasm accessions were obtained from the National Agrobiodiversity Center, National Academy of Agricultural Science, Rural Development Administration, and USA accessions from the Plant Genetics and Breeding Laboratory of Kyungpook National University, Korea. The oil content ranges from 12.7~26.0% with an average of 19.1% among accessions. The average contents and ranges of palmitic and stearic acid, saturated fatty acids (SFA), were 10.6% with a range of 4.1~18.1% and 2.9% with a range of 1.9~ 12.7% respectively, while those of oleic, linoleic and linolenic acid, unsaturated fatty acids (USFA), were 28.2% with a range of 15.3~56%, 51.2% with a range of 24.4~68% and 7.1% with a range of 3.4~11.1% respectively. The average linoleic(ω -6)/linolenic(ω-3) acid ratio was 7.5 ranging from 3.8~17, and the average SFA and USFA contents were 13.5% ranging from 6.7~21.7% and 86.5% ranging 78.3~93.4% respectively. Accessions with better essential properties were selected as useful resources for the development of high oil content and quality fatty acid varieties. Three accessions, Suinong 14, Dongnong 434 and Dongnong 46 from China contain oil higher than 25.0%, while five accessions including KLG 12073 and KLG 12074 from USA, Jilin 14 from China, Kwangan and Bongeui from Korea contain oleic acid higher than 50%. Eight accessions including KLG12083 and KLG12081 from USA contain linoleic acid higher than 60%. Seven accessions including KLG 12093 and KLG12096 from USA contain linolenic acid lower than 4%. Five accessions, KLG12074 and KLG12073 from USA, Kwangan and Bongeui from Korea, and Dongnong 47 from China were low linoleic acid(ω-6)/linolenic(ω-3) ratio resources with lower than 4.5.