Genome-Wide Association Study and Marker Development for Root Rot Resistance in Soybean.

root rot (FORR) is an important disease threatening soybean production. The development of marker-assisted selection (MAS) molecular markers will help accelerate the disease resistance breeding process and achieve the breeding goal of improving soybean disease resistance. This study evaluated the FORR disease resistance of 356 soybean germplasm accessions (SGAs) and screened resistance-related loci using genome-wide association analysis (GWAS) to develop molecular markers for MAS. A total of 1,355,930 high-quality SNPs were analyzed, 150 SNP sites significantly associated with FORR resistance were identified, and these sites were distributed within 41 QTLs. Additionally, 240 candidate genes were screened near these QTL regions, involving multiple functions such as hormone metabolism, signal transduction, stress defense, and growth regulation. Cleaved amplified polymorphic sequence (CAPS) and Kompetitive Allele-Specific PCR (KASP) molecular markers were developed based on candidate genes with significant SNP loci and beneficial haplotypes. The CAPS markers, S15_50486939-CAPS1 and S15_50452626-CAPS2, can effectively distinguish resistant and sensitive genotypes through enzyme digestion. The KASP marker is based on S07_19078765-G/T and exhibits a genotype clustering pattern consistent with disease resistance, demonstrating its application value in breeding. The CAPS and KASP markers developed in this study can provide reliable tools for MAS in FORR disease-resistant varieties. The research results will help reveal the genetic structure of FORR disease resistance and provide support for efficient breeding.