Breeders typically use core collections of a specific trait or core collections selected by a few genotypes to efficiently select breeding materials or to study functional genes. As a result, many accessions have been deemed redundant or duplicated and are no longer considered for use. This study aimed to investigate the agronomical characteristics and genetic diversity of 1,514 previously unused and unstudied wheat germplasms and to confirm their value as breeding materials using population structure analysis. The performance of these wheat germplasms was compared with that of 8,878 wheat breeding materials and 72 known Korean wheat cultivars. The results of agronomic trait diversity comparison showed that the germplasm populations used for breeding research did not completely encompass the unused germplasm populations. The agronomic traits of wheat germplasms varied greatly. ANOVA and PCA results revealed the greatest differences in growth habits (CV=0.339), panicle length (CV=0.330), and awn length (CV=0.296). To accurately assess the value of unused wheat germplasms as breeding materials, 106 SSR markers were extracted from the analysis of four representative Korean cultivars: Geuru, Geumgang, Uri, and Jokyoung. Among these, 24 SSR markers were chosen, and 129 wheat resources were subjected to population structure analysis, which revealed five subpopulations. Most of the 34 germplasms that originated in Korea were distributed in subpopulation 1 (18 accessions, 52.9%) and subpopulation 4 (12 accessions, 35.3%). Subgroups 2, 3, and 5 differed significantly in agronomic traits and genotypes, indicating their potential as breeding materials. The findings of this study could serve as a foundation for breeders and aid in the discovery and utilization of new wheat breeding materials.

In this study, composition and agronomic traits, including yield-related traits, were investigated and compared among 35 Korean landrace germplasm for two years (2019 and 2020). The contents of 12 isoflavones were measured using high-performance liquid chromatography, and agronomic trait data were collected according to the Rural Development Administration criteria. Comparing isoflavone composition between the two years, all isoflavones, except glycitein, were generally higher in 2019. The values of yield-related and major agronomic traits decreased in most accessions in 2020. ANOVA showed highly significant differences (p<0.001) in genotypes, years, and genotype-by-year interaction for all isoflavones, the number of pods per plant, and 100-seed weight. The number of seeds per pod, days to flowering, and days to maturity also showed significant differences among genotypes, as well as between the two years. Correlation analysis revealed that daidzin and genistin were positively correlated with their malonylated form. Malonyl daidzin was also positively correlated with malonyl genistin levels. The accessions with the least variation in the total isoflavone content were IT 153844 (907.5 µg/g, 898.6 µg/g) and IT 252252 (663.2 µg/g, 636.4 µg/g). Some of the evaluated landraces will be a promising genetic source for developing soybean varieties with high levels of environmental stability in isoflavone content and agronomic traits.