Angular Leaf Spot Resistance Loci Associated with Different Plant Growth Stages in Common Bean

Angular leaf spot (ALS) is a disease that causes major yield losses in the common bean crop. The aim of the present study was to identify ALS resistance loci at different plant growth stages (PGS) by QTL mapping. We sequenced an BC2F3 inter-gene pool cross population (AND 277 x IAC-Milenio - AM population) through genotyping by sequencing (GBS), and constructed a multi-point genetic linkage map. The population was evaluated for ALS resistance at the V2 and V3 PGSs (controlled conditions) and R8 PGS (field conditions), and the data was used to search for QTL (quantitative trait loci) using the multiple interval mapping (MIM) method. Different QTLs were detected for the three PGSs, showing a different quantitative profile of the disease at different plant growth stages. Several loci also validated regions of previous studies. The results of the present study can be used to develop new specific molecular markers, representing a powerful tool for common bean crop improvement and for gain in ALS resistance.