Genetic diversity and phylogeny of tea plant (Camellia sinensis) and its related species and varieties in the section Thea genus Camellia determined by randomly amplified polymorphic DNA analysis

The genetic diversity and molecular phylogeny of tea plant (Camellia sinensis) and its 23 related species and varieties were investigated by randomly amplified polymorphic DNA (RAPD) analysis. Fifteen decamer oligonucleotide primers were selected from the 61 screened. A total of 102 polymorphic bands (6.8 diversity/primer) out of 107 reproducible products (7.1 fragments per primer) were amplified from the selected 15,primers, corresponding to 95.3% diversity of the amplification bands. The molecular phylogenetic dendrogram of section Thea was constructed using UPGMA and basing on Nei and Li's similarity coefficient from pairwise comparisons of RAPD data between 24 species and varieties. According to the dendrogram, there were two groups, corresponding to 3- and 5-locule ovary in morphology. There were two and three subgroups in each group, respectively. The genetic relationship and the molecular phylogeny among section Thea were discussed. RAPD not only confirmed a large body of morphological classification and evolution of section Thea of the genus Camellia proposed in previous work, but also provided novel and robust evidence of the genetic diversity and phylogeny of the tea plant and its related species.