Genomic Regions Associated with Resistance to Soybean Cyst Nematode ( Heterodera glycines Ichinohe) Population HG Type 1.2.5.7 in Dry Beans ( Phaseolus vulgaris L.)

Ichinohe, 1952). Host resistance is an effective management strategy, yet resistance to the virulent SCN population HG type 1.2.5.7 has not been genetically characterized in dry beans. In this study, 170 dry bean genotypes (113 breeding lines/cultivars and 57 germplasm accessions) were evaluated for response to HG type 1.2.5.7 under controlled conditions using female index (FI) as the resistance phenotype. FI values ranged from 4.1% to 78.1%, with one genotype (PI 313733) classified as resistant, 35 moderately resistant, 104 moderately susceptible, and 30 susceptible. Genome-wide association analysis using 2,044 single-nucleotide polymorphism (SNP) markers from the 3.8K Bean Panel chip and the BLINK model identified four significant marker-trait associations on chromosomes Pv02, Pv05, Pv07, and Pv11. Linkage disequilibrium-defined candidate intervals spanned 108 kb (Pv02), 1.50 Mb (Pv05), 798 kb (Pv07), and 1.45 Mb (Pv11), collectively containing 126 annotated genes: 20 on Pv02, 39 on Pv05, 35 on Pv07, and 32 on Pv11. The intervals contained putative genes annotated for signaling and transcriptional regulation, cell wall and carbohydrate metabolism, transport, and secondary metabolism. Together, these findings indicate that the response to HG type 1.2.5.7 in dry bean is quantitative and associated with multiple genomic regions. The identified intervals provide candidate targets for independent validation, fine mapping, functional analysis, and future marker development to support breeding for SCN resistance.