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

Abstract

Powdery mildew (PM), caused by the biotrophic fungus Podosphaera xanthii, drastically reduces the yield and quality of melon (Cucumis melo L.). Knowledge of the genetic control and high throughput molecular markers linked with resistance against this 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 three SNP based high resolution melting markers, PMm-HRM-1, PMm-HRM-2, and PMm-HRM-3, based on the previously identified SNPs on chromosome 12 and validated them using 8 melon lines and 137 F2 populations. Among these, the SNP of marker PMm-HRM-1 causes a missense mutation in the LRR region of MELO3C002393 and we were able to distinguish the resistant vs susceptible genotypes from eight diverse melon accessions and the segregating F2 population with more than 90% genotyping efficiency. The other two markers were based on intergenic SNPs and had more than 80% genotyping efficiency in F2 population. These markers will be helpful to melon breeders to develop melon cultivars resistant to P. xanthii race 5 via marker assisted breeding programs.

Identification of Gene Responsible for Conferring Resistance against Race KN2 of Podosphaera xanthii in Melon

“…Based on the genetic analysis, it is reported to carry two independent genes, one dominant and one recessive [69]. Similarly, the PMR 5 resistant line carries a single dominant gene against race 5 of Px [70]. Similarly, another dominant gene was reported from the PI 371795 cultivar and named the Pm-1 gene.…”

Developing DNA Markers based on Male-Specific Chromosomal Regions for Selecting Male Plants in Hop (Humulus lupulus)

“…Molecular breeding methods, such as marker-assisted selection (MAS) (Hong et al 2022), have the potential to determine the sex of hop plants before phenotypic differences. Although a few markers have been developed, their quality could be enhanced using Y chromosome-specific sequences (Cerenak et al 2019;Patzak et al 2002).…”