Submitted to: Systematic Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/5/2008
Publication Date: 5/21/2008
Citation: Spooner, D.M., Salas, A., Ames, M. 2008. Revision of the Solanum medians complex (Solanum section Petota). Systematic Botany. 33(3):579-588. Interpretive Summary: The cultivated potato of world commerce, technically known as Solanum tuberosum, contains many wild species relatives that are of use as breeding stock to improve traits of the potato crop such as improved disease resistance, higher yields, and improved processing qualities such as the ability to produce better fries and chips. The USDA funds the taxonomic characterization of these wild species because taxonomy provides breeders guides to the choice of species to use in their breeding programs. Twenty years ago there were 232 wild potato species recognized, but taxonomic work since then has continued to reduce this number to a latest estimate of 188 species, and continuing taxonomic work is continuing to reduce this number. This study reexamines the number of species in the “Solanum medians complex, a group of very similar species growing along the coast and the western slopes of the Andes Mountains from central Peru to northern Chile. It places in synonymy eleven names, including four species that are currently accepted, reducing the currently accepted number of potato species to 185. We consider this reduction in potato species to be one of many needed studies to further reduce the number of potato species, and we are continuing this research. The revised taxonomy to result will be an improvement in that it will recognize more natural species, the taxonomy will be easier to use, and the species will ideally have better use to breeders in choosing species to use in their potato improvement programs.
Technical Abstract: Solanum medians is a widely distributed wild potato species growing along the coast and along the western slopes of the Andes from central Peru and northern Chile, from along the coastal lomas near sea level to 3800 m. Fertile diploid and triploid cytotypes are common, are believed to associated with morphological variants, and formally named as subspecies. Our morphological study from herbarium specimens examines the support for these subspecies and other currently recognized species that are similar to S. medians. We synonymize under S. medians eleven names, including the following six names recently accepted as good taxa: S. medians. var. autumnale, S. neoweberbaueri, S. sandemannii, S. tacnaense, and S. tacnaense f. decurrentialobum, and S. weberbaueri. We consider this synonymy to be part of a much larger need for the reduction of names in sect. Petota, research currently in progress.