Molecular phylogeny and DNA amplification fingerprinting of Petunia species

The relationships of four wild species of Petunia (Petunia spp. Juss.) and ten cultivars of the cultivated petunia (P. xhybrida Hort.) were investigated using DNA Amplification Fingerprinting (DAF). Amplification and separation of DNA products of petunia produced reproducible banding profiles. Consistencies were found among profiles of the variable Petunia taxa by bulking the tissue from ten different plants. Each of the ten octamer primers selected for use throughout the study revealed polymorphic loci between the species and cultivars. Among the total 201 bands produced, 146 (73%) loci were polymorphic and these could be used to distinguish between each of the species and cultivars. Scoring for presence and absence of the amplified bands was used to generate a phylogenetic tree and to calculate the pairwise distances between each of the taxa using parsimony (PAUP) analysis. The tree generated using DAF molecular markers was the first study to separate P. axillaris from P. parodii and to distinguish between the violet flowered species, P. Inflata, P. violacea, and P. integrifolia. Petunia parodii was included on the same branch with the ten cultivars of P. xhybrida, indicating it had a major contribution in the development of the cultivars. Divisions within the branch of cultivars were by color. The average genetic distance was 62 among species P. axillaris, P. parodii, P. inflata, P. violacea and P. integrifolia and 44 among cultivars of P. xhybrida. The results demonstrated the utility of DAF for establishing relationships among closely related species and cultivars of petunia.