Implications for the Phylogeny, Classification, and Biogeography of Solanum from cpDNA Restriction Site Variation

Abstract

A phylogenetic analysis of Solanum based on chloroplast DNA restriction site variation confirms previous findings that Lycopersicon and Cyphomandra are derived from within Solanum. Three out of four Solanum subgenera with more than one representative in this analysis (Minon, Potatoe, Solanum) are found to be polyphyletic, suggesting that the subgeneric classification of the genus needs revision. Subgenus Leptostemonum is monophyletic within the context of our sampling. Three primary clades can be distinguished within Solanum. Clade I includes representatives of sections Archaesolanum, Dulcamara, Holophylla, Jasminosola- num, and Solanum. Clade II includes members of subgenus Potatoe (sections Basarthrum, Lycopersicon, and Petota). Clade III includes all representatives sampled from subg. Leptostemonum, sects. Allophyllum, Brevan- therum, Gemninata, Pseduocapsicum, and Cyphomandropsis, and species formerly assigned to Cyphomandra. Solanum as a whole and each of the three primary clades apppear to be New World in origin. Within Leptostemonum, African and Australian members are derived from New World ancestors.