Marker-assisted Selection For Blight, Powdery Mildew,Gummy Stem Blight Resistant Genes In Melon

Melon (Cocumis melo. L) is one of the most important horticultural crops which is widely cultivated in the temperate and tropical regions. Fusarium wilt, powdery mildew and gummy stem blight are three major diseases world-wide in melon, which have a huge impact on melon’s yield and quality. Physical, chemical and biological control of these diseases is ineffective. Therefore, identification of disease-resistant germplasms and breeding new varieties is the most effective and fundamental way to eliminate these diseases.This research was based on utilizing the molecular markers to identify fusarium wilt, powdery mildew and gummy stem blight disease resistant melon germplasms. During distant hybridization and backcross between thick-skin muskmelon and thin-skin muskmelon, disease-resistant melon germplasms were identified by marker-assisted selection(MAS). The main research results are as follows:1Identification of disease-resistant germplasms17varieties of melon germplasms have been identified based on a FMs which is resistant to race0,1of Fusarium oxysporum f.sp.melonis, an SCAR marker-SV04574which is resistant to race0,1of Fusarium oxysporum f.sp.melonis, a powdery mildew-resistant SCAR marker and a gummy stem blight-resistant ISSR marker. We got14materials resistant to race0,1of Fusarium oxysporum f.sp.melonis and16materials resistant to race0,2of Fusarium oxysporum f.sp.melonis,13materials resistant to powdery mildew,14materials resistant to gummy stem blight.2Distant hybridization and backcross of melonTwo thick-skin muskmelon species and a thin-skin muskmelon species were used to proceed distant hybridization and backcross. The four kinds of molecular markers have been used in screening resistant plants in F1， BC1,BC2groups. Through which,17Fi plants with fusarium wilt-resistant gene, include one plant resistant to powdery mildew,37BCi plants with fusarium wilt-resistant gene,13BC2plants with fusarium wilt and gummy stem blight-resistant gene have been identified. 3Observation of phenotype of backcross descendants and fruit testingVia observation of phenotype of backcross descendants in the field, we found the resistance has been greatly improved without any weakening in flavor compared to thick-skin muskmelon parents. The result illustrated that the MAS is an efficient way to select new cultivars possessing disease resistance and high quality.