Map Construction And Powdery Mildew Resistant Gene Location Of Melon(Cucumis Melo L.)

Our country is a big consumer of melon. In hot and humid summer, melon is very easy to infect powdery mildew. Frequently a large area of melon infecting powdery mildew caused produce nothing.However, chemical control powdery mildew not only becomes resistant but also pollutes environment.This contraries to the purpose of green production.With the rise of biotechnology in recent years, molecular breeding methods has instead the traditional cross-breeding, which greatly reduces the breeding time and speeds up the breeding process. Powdery mildew-resistant melon line MR-1 and powdery mildew-susceptible line Topmark were used as female and male parent, respectively, to develop F2 population in this test. Two parents were selected for international physiological races differential hosts, including disease-resistant inbred MR-1 as female susceptible inbred Topmark male parent.MR-1 and Topmark obtained F1 hybrids then F1 generation of strict self- pollination get F2 generation. All 354 plants of F2 were from the same generation F1 of melon.For 354 F2 populations, 20 MR-1(P1), 20 Topmark(P2), 20 F1,100 strain BC1P1(F1 backcrossed with P1) and 100 BC1P2(F1 backcrossed and P2) seeded in the greenhouse,which were used to survey powdery mildew resistance.Disease index level were calculated and analyzed their genetic construction.As a result a single dominant gene conctroled powdery mildew were found. By powdery mildew-resistance field investigation of 13 differential hosts, we found that melon powdery milde was caused by P. xanthii race 1. According to two parental genome re-sequencing data, designed and developed CAPS markers 316 pairs. In the two parental screening among 157 pairs of polymorphic primers polymorphic rate of 49.80%.According to genome re-sequencing data of parents, we developed CAPS markers for genotyping of F2 plant and genetic linkage mapping. As a result, a genetic linkage map contained 12 linkage groups covering a total length of 2,065.47 c M included 142 CAPSs was constructed. Average distance was 14.55 c M. The most marker abundant linkage group was LG4, which included 22 CAPSs, average distance was 11.61 c M. The longest linkage group was LG5, which covered length of 277.98 c M, the shortest linkage group was LG3, which covered length of 65.6 c M. A powdery mildew-resistance related locus in LG7, which located between CAPS marker 7-4E and 7-1H was obtained.