Abstract
Soybean [Glycine max (L.) Merr.] is a commercially important oil and protein-producing crop. This study explored genetic variation in seed traits to improve soybean productivity. Phenotypic data, including seed size, length, width, thickness, and weight, were analyzed across 344 Korean soybean accessions, identifying 100-seed weight (100SW) as one of the important yield components in soybean. Using 4,472,823 high-density single-nucleotide polymorphism (SNP) markers, a genome-wide association study detected 10 novel loci associated with 100SW on chromosomes 3, 4, and 19. Haplotype analysis revealed that the accessions with alternative alleles at nine candidate loci displayed significant variation in 100SW, either increasing or decreasing weight. Allele stacking analysis further highlighted that favorable variants, particularly on chromosomes 3 and 19, had additive genetic effects on 100SW. Functional annotations suggest these genes influence seed weight through gibberellin synthesis and developmental pathways. By leveraging high-density genomic data, this study overcomes the limitations of previous studies relying on low-density markers, offering a foundation for more efficient soybean breeding strategies. These findings offer valuable insight into marker-assisted selection, providing a foundation to enhance soybean yield and adaptability under diverse environmental conditions and addressing the growing global demand for sustainable food production.