Apple scab caused by Venturia inaequalis has a tendency to spread and threatens the development of apple production in recent years in China.The genetic diversity and population structure were investigated by using simple sequence repeat(SSR) markers.51 strains were classified into 3 groups by UPGMA method as Xunyi,Xingping and U.K.population,each of them mainly including strains from its original place.A relatively high level of genetic diversity was revealed: H=0.425 3,I=0.675 8,PPL=66.67%(at species level);H=0.149 1,I=0.228 0,PPL=44.44%(at population level).A high level of genetic differentiation was detected among/within populations with Nei’s Gst analysis and AMOVA.Molecular genetic variance within populations was greater than that among populations.Genetic variance among populations might result from barriers to gene flow(Nm=0.675 8).Genetic variance within populations might result from sexual pro-pagation of V.inaequalis.
