Inheritance of Resistance to Race 5 of Powdery Mildew Fungus Podosphaera xanthii in Melon and Development of Race 5-Specific High Resolution Melting Markers

Inheritance of Resistance to Race 5 of Powdery Mildew Fungus Podosphaera xanthii in Melon and Development of Race 5-Specific High Resolution Melting Markers

Powdery mildew (PM), caused by the biotrophic fungus Podosphaera xanthii, drastically reduces the yield and qualityof melon (Cucumis melo L.). Knowledge of the genetic control and high throughput molecular markers linked with resistance againstthis disease are essential for breeding programs. The bioassay study of the F1 and F2 populations derived from the parents, ‘PMR 5’ (♂)and ‘SCNU1154’ (♀) revealed a monogenic dominant nature of resistance to the devastating race, race 5. Besides, we developed threeSNP based high resolution melting markers, PMm-HRM-1, PMm-HRM-2, and PMm-HRM-3, based on the previously identified SNPson chromosome 12 and validated them using 8 melon lines and 137 F2 populations. Among these, the SNP of marker PMm-HRM-1causes a missense mutation in the LRR region of MELO3C002393 and we were able to distinguish the resistant vs susceptiblegenotypes from eight diverse melon accessions and the segregating F2 population with more than 90% genotyping efficiency. The othertwo markers were based on intergenic SNPs and had more than 80% genotyping efficiency in F2 population. These markers will behelpful to melon breeders to develop melon cultivars resistant to P. xanthii race 5 via marker assisted breeding programs.