Development and validation of KASP markers for resistance to Phytophthora capsici in Capsicum annuum L

Resistance of Capsicum annuum to Phytophthora blight is dependent on the genetic background of the resistance source and the Phytophthora capsici isolate, which poses challenges for development of generally applicable molecular markers for marker-assisted selection. In this study, the resistance to P. capsici of C. annuum was genetically mapped to chromosome 5 within a 1.68-Mb interval by genome-wide association study analysis of 237 accessions. In this candidate region, 30 KASP markers were developed using genome resequencing data for a P. capsici -resistant line (0601 M) and a susceptible line (77,013). Seven of these KASP markers, located in the coding region of a probable leucine-rich repeats receptor-like serine/threonine-protein kinase gene ( Capana05g000704 ), were validated in the 237 accessions, which showed an average accuracy of 82.7%. The genotyping of the seven KASP markers strongly corresponded with the phenotype of 42 individual plants in a pedigree family (PC83-163) developed from the P. capsici -resistant line CM334. This research provides a set of efficient and high-throughput KASP markers for marker-assisted selection of resistance to P. capsici in C. annuum .