Segregating population consisting of F₁,BC₁P₁,BC₁P₂ and F₂ were generated by crossing the resistant inbred line PI511890 with the susceptible inbred line‘Baipicui’.The resistance of segregating population and parental lines were evaluated by inoculating spore isolates of gummy stem blight at seeding stage.The results indicated that:(1)The resistance to gummy stem blight in PI511890 is controlled by a single dominant gene.(2)Using bulked segregation analysis,an unique 900 bp fragment was amplified in resistant materials with the primer ISSR-100.It was confirmed that the marker ISSR-100₉₀₀ was linked to the gene Gsb-3.(3)The polymorphic patterns of ISSR-100 in the 182 individuals of F₂ were scored and then calculated by the software of JoinMap 4.0.The results showed that the genetic distance between ISSR-100 and Gsb-3 is 8.3 cM.This ISSR band indicated that the marker could be useful for marker assisted selection in melon breeding for gummy stem blight resistance.