Phylogenetic relationships in Solanum (Solanaceae) based on ndhF sequences

A phylogenetic analysis was conducted using sequence data from the chloroplast gene ndhF. Sequences were obtained from 25 species of Solanaceae, including 18 species of Solanum representing five of the seven conventionally recognized subgenera. Trees were constructed using parsimony and maximum Likelihood methods. Results indicate that Solanum lycopersicum (formerly in genus Lycopersicon) and Solanum betaceum (formerly in genus Cyphomandra) are nested within the Solanum clade. Each of the Solanum subgenera Leptostemonum, Minon, Potatoe, and Solanum are not monophyletic as currently circumscribed. Four major clades within Solanum are supported by high bootstrap values, but the relationships among them are largely unresolved. The problematical sections Aculeigerum (represented by S. wendlandii) and Allophyllum (represented by S. allophyllum) emerge as sister taxa in a larger clade composed of S. betaceum, S. luteoalbum, and members of subgenera Leptostemonum, Minon, and Solanum. Several prominent morphological characters such as spines, stellate hairs, and tapered anthers apparently have evolved more than once in Solanum.