Genetic diversity in 122 accessions of pummelo (Citrus grandis Osbeck) and its related varieties was assessed using simple sequence repeat (SSR) markers. Thirty-one pairs of SSR informative primers generated a total of 335 alleles. The average number of alleles per locus was 9.85. The value of allelic polymorphism information content (PIC) ranged from 0.1939 to 0.9073, with an average of 0.7085 per primer. The 122 accessions of pummelo and its related varieties could be clustered into seven groups by the unweighted pair-group method arithmetic average (UPGMA), in which the 110 pummelo accessions could be divided into 18 subgroups at similarity coefficient of 0.712. These subgroups were mainly composed of the Shatian pummelo variety group, the Wendan variety group and many of the hybrid pummelo groups. The classification method can be used in targeting many varieties in order to widen the genetic background of pummelo.
