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Cercospora leaf blight (CLB), caused by Cercospora cf. flagellaris, C. kikuchii, and C. cf. sigesbeckiae, is a significant soybean [Glycine max (L.) Merr.] disease in regions with hot and humid conditions causing yield loss in the United States and Canada. There is limited information regarding resistant soybean cultivars, and there have been marginal efforts to identify the genomic regions underlying resistance to CLB. A Genome-Wide Association Study was conducted using a diverse panel of 460 soybean accessions from maturity groups III to VII to identify the genomic regions associated to the CLB disease. These accessions were evaluated for CLB in different regions of the southeastern United States over 3 years. In total, the study identified 99 Single Nucleotide Polymorphism (SNPs) associated with the disease severity and 85 SNPs associated with disease incidence. Across multiple environments, 47 disease severity SNPs and 23 incidence SNPs were common. Candidate genes within 10 kb of these SNPs were involved in biotic and abiotic stress pathways. This information will contribute to the development of resistant soybean germplasm. Further research is warranted to study the effect of pyramiding desirable genomic regions and investigate the role of identified genes in soybean CLB resistance. [ABSTRACT FROM AUTHOR]

Charcoal rot of soybean [Glycine max (L.) Merr.], caused by the soilborne fungus Macrophomina phaseolina (Tassi) Goid., has ranked among the most important soybean diseases in the United States. Disease management is typically done in a multifaceted approach through crop rotation, tillage, irrigation, and seed treatments aimed at minimizing damage caused by the pathogen. Development of genetic resistance to charcoal rot appears to be the most efficient strategy to control the disease; however, there are no reports of genetic regions associated with resistance to the disease. The objective of this study was to identify quantitative trait loci (QTLs) governing resistance to charcoal rot in soybean using a biparental population of PI 567562A (resistant) × PI 567437 (susceptible). A total of 140 F2–derived lines were genotyped with 5403 single nucleotide polymorphism (SNP) markers covering 20 chromosomes, of which 2283 were polymorphic. Resistance to charcoal rot was evaluated in the F2:3 lines using the cut‐stem inoculation technique under greenhouse conditions. The QTL mapping analysis indicated one QTL on chromosome 15 explaining 29.4% of phenotypic variation, and two QTLs on chromosome 16 explaining 25.4 and 8.4% of phenotypic variation for resistance to M. phaseliona. To our knowledge, this is the first report of genomic regions harboring resistance to charcoal rot in soybean, and it may facilitate breeding and molecular engineering progress to combat charcoal rot disease in the future. [ABSTRACT FROM AUTHOR]

Charcoal rot, caused by Macrophomina phaseolina in soybean [ Glycine max (L).Merr.] is a disease of economic significance in the United States. Chemical and cultural control are not effective and host resistance could be a potential method to control the disease. In this study we report the use of bulked-segregant analysis (BSA) to map the genetic basis of resistance to charcoal rot in soybean PI 567562A, using a QTL-seq approach. Resistant and susceptible bulks from progenies of a biparental population (PI 567562A and PI 567437) were sequenced, and reads were aligned to the PI 567562A genome and used to calculate the SNP-index at each SNP position for the resistant and susceptible bulks. The average distributions of the SNP-index and Δ SNP-index across the genome were estimated for genomic intervals using a sliding window analysis with 2-Mb window size and a 10-kb step. Three genomic regions on chromosomes 5, 8 and 14 were identified with positive values in Δ SNP-index plots that potentially correspond to QTL governing the difference between the R-bulk and S-bulk sub-populations. The current study is the first attempt employing QTL-seq to identify genomic regions that may contain QTL controlling charcoal rot disease resistance in soybean. • Genetic basis of resistance to charcoal rot in soybean. • QTL-seq approach with next-generation sequencing (NGS). • Bulked-segregant analysis (BSA). [ABSTRACT FROM AUTHOR]