Abstract: Genetic diversity of 220 wild Rosa roxburghii accessions was investigated using 10 EST-SSRs and quality traits. A total of 33 alleles were amplified by 10 pairs of EST-SSR primers，in which polymorphic alleles was 27. The polymorphic percentage was 76.67%. The coefficients of variation of 9 quality traits were all greater than 10%，in which the average fruit weight，titratable acid，total soluble solid/titratable acid，vitamin C and flavonoids content were above 20%. The 220 wild R. roxburghii germplasm resources in Guizhou were rich in genetic diversity in a wide range，suitable for the construction of the core collection. Nine quality traits were each further classified into 6 grades，treated as that 54 polymorphic alleles，were produced by 9 quality markers，together with EST-SSR markers，were performed for UPGMA clustering using Nei’s genetic distance. At the same time，the core collection was constructed by using the allele preferred sampling strategy. The ratio of phenotype retained，mean difference percentage，variance difference percentage，coincidence rate of range，changeable rate of coefficient of variation，percentage of polymorphic loci，Nei’s gene diversity index and Shannon’s information index were used to evaluate core collection. Principal coordinate analysis method was used to confirm core collection. Results showed that the 32 core collections can represent the genetic diversity of the original germplasm at the molecular level，the phenotypic level and the regional distribution.

Key words: Rosa roxburghii, EST-SSR, fruit quality, genetic diversity, core collection