Genetic Dissection of Bentazone Tolerance Loci in Cultivated Soybeans: A Genome-Wide Association Study

Weeds alone cause a 37% loss in attainable soybean production. Bentazone is a postemergence herbicide used to control broadleaf weeds in the cultivation of cereals, legumes, vegetables, and tuber crops. This study aimed to screen the Korean collections of cultivated soybeans in relation to bentazone, identifying the genetic loci controlling bentazone reactions to cultivated soybean collections using a genome-wide association study (GWAS). This study identified bentazone-tolerant and bentazone-sensitive soybean germplasms from 418 cultivated soybean germplasms and found that moderate bentazone tolerance predominated in the Korean collection of cultivated soybeans. The GWAS revealed that 42 SNPs distributed on chromosomes 3, 5, 6, 13, and 20 were strongly associated with the bentazone reaction in 418 cultivated soybean accessions over three years. Of these loci, a genomic region on chromosome 5 contained significant SNPs and was identified as being involved in the bentazone reaction in both 2020 and 2021, based on FarmCPU analysis. By conducting a haplotype analysis, this study identified five putative genes, namely, Glyma.05g145000 (ATP-binding cassette transporter), Glyma.05g145100 (unknown), Glyma.05g145200 (ankyrin repeat family protein), Glyma.05g145300 (transmembrane amino acid transporter protein), and Glyma.05g145400 (unknown). Further studies are required to confirm the involvement of the putative genes in the bentazone reaction by comparing their expression levels between bentazone-tolerant and bentazone-sensitive plants. Therefore, the results of this study can be used for marker-assisted selection in programs for the breeding of herbicide-tolerant soybeans.