Abstract: Segregating population consisting of BC₁F₁，BC₂F₁ and F₂ were generated by crossing the resistant inbred line PI482398[male parent，containing gene the Gsb-4 resistant to gummy stem blight（GSB）]with the susceptible inbred line‘Baipicui’（female parent）. The resistance of segregating population and parental lines were evaluated by inoculating spore isolates of GSB at seeding stage. The results indicated that resistance to GSB in PI482398 is controlled by a single dominant gene. The bulked segregant analysis（BSA）was employed to screen the resistant and susceptible DNA pools with 89 pairs of SSR primers as tool. An unique 120 bp fragment was amplified in resistant materials with the primer CMTA170a. The polymorphic patterns of CMTA170a in the 118 individuals of F₂ were scored and then calculated by the software of MAPMAKER/Exp version 3.0 b. The results showed that the genetic distance between CMTA170a and Gsb-4 is 5.14 cM.

Key words: melon, gummy stem blight, Gsb-4, SSR