Genome-wide association study of resistance to anthracnose and angular leaf spot in Brazilian Mesoamerican and Andean common bean cultivars

Anthracnose (ANT) and angular leaf spot (ALS) are devastating diseases of common bean (Phaseolus vulgaris L.) worldwide, and identification of new sources of ANT and ALS resistance is a major priority in breeding programs. The ANT and ALS reaction of 57 Andean and 58 Mesoamerican accessions from five Brazilian states were evaluated. Three Mesoamerican and eight Andean accessions were resistant to races 9, 65, 73, 2047, and 3481 of the ANT pathogen, while four Mesoamerican and 14 Andean accessions were resistant to four of the ANT pathogen races. Furthermore, 13 Mesoamerican and 30 Andean accessions were resistant to races 31-23 and 63-39 of the ALS pathogen. To understand the genetic basis of ANT and ALS resistance, a genome-wide association study (GWAS) was conducted using the 115 accessions, revealing new sources of resistance in Andean and Mesoamerican accessions. The single nucleotide polymorphism (SNP) markers associated with races 9 and 73 of ANT was positioned on chromosome Pv04; resistance to race 65 on chromosomes Pv01, Pv04, and Pv08; and resistance to races 2047 and 3481 on chromosomes Pv10 and Pv05, respectively. Furthermore, SNPs associated with race 31-23 of Pseudocercospora griseola (Sacc.) Crous & U. Braun were mapped on chromosomes Pv02 and Pv04, whereas for race 63-39, SNPs were mapped on chromosomes Pv03, Pv06, and Pv08. The SNP markers and candidate genes found associated with the resistance should be validated in segregating populations, which could further be used for marker-assisted selection. As a result, breeding programs might be able to develop resistant bean cultivars to ANT and ALS.