Development of InDel Marker for Melon Resistance to Downy Mildew Based on BSA Resequencing

【Objective】 o obtain molecular markers of melon downy mildew resistance genes, and improve the accuracy and scientific city of melon downy mildew resistance traits selection. 【Methods】 The F₂ generation segregation population was constructed by hybridization between wild high-resistant downy mildew resource DM-4 and susceptible inbred line DM-2BSA-seq was used to locate and regulate the candidate interval of downy mildew resistance gene in melon InDel molecular markers. parents and their F₂ individuals were used for screening and verification. 【Results】 Genes regulating melon downy mildew resistance are located on 9th chromosome. 37 InDel molecular markers were developed in the candidate region, and 9 of them showed differences in the size of PCR products between resistant and susceptible parents. Further verification was carried out with F₂ plants. Combined with field phenotypic identification results, the accuracy rates of primer InDel 15 and InDel 20 were 95 % and 98 %, respectively. The amplified products of primer InDel 15 and InDel 20 in resistant parents were 251 bp and 349 bp, respectively, and 231 bp and 324 bp, respectively. 【Conclusion】 Primers InDel 15 and InDel 20 can be used as molecular markers for downy mildew resistance breeding, which can accelerate the breeding speed of melon downy mildew resistance and lay the foundation for further cloning the main genes of melon downy mildew resistance.