Abstract: Inter-Simple Sequence Repeat(ISSR) molecular markers were used to analyze the genetic relationships of 14 Phalaenopsis cultivars with different origins and colors. Using 14 primers, we amplified 179 bands, of which 147 bands are polymorphic, and the average percentage of polymorphic bands was 82%. The range of genetic similarity was 0.734~0.936, suggesting that the substantial genetic divergence between some cultivars. ISSR markers represent a useful method for cultivar identification of Phalaenopsis, all 14 cultivars could be distinguished by these ISSR markers and 20 cultivar-specific ISSR bands were obtained for 10 of the 14 Phalaenopsis cultivars tested. Cluster analysis classified the 14 cultivars into 2 major groups. The result of UPGMA (unweighted pair-group method using arithmetic averages) clustering analysis was generally consistent with color, but there were some exceptions between clustering result and flower colors which may result from hybridization between cultivars. Article also discussed the instructional significance of experiment’s result to Phalaenopsis breeding.

Key words: Phalaenopsis, ISSR markers, genetic relationships, cultivar identification