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ARS Home » Midwest Area » Madison, Wisconsin » Vegetable Crops Research » Research » Publications at this Location » Publication #315215
Title: Relationships among wild relatives of tomato, potato, and pepino

Author
item TEPE, ERIC - University Of Cincinnati
item ANDERSON, GREGORY - University Of Connecticut
item Spooner, David
item BOHS, LYNN - University Of Utah

Submitted to: Taxon
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/25/2015
Publication Date: 5/3/2016
Publication URL: http://handle.nal.usda.gov/10113/62490
Citation: Tepe, E.J., Anderson, G.J., Spooner, D.M., Bohs, L. 2016. Relationships among wild relatives of tomato, potato, and pepino. Taxon. 65(2):262-276. doi: http://dx.doi.org/10.12705/652.4.

Interpretive Summary: The tomato and potato family, technically referred to as the Solanaceae family, contains some 1500 species. Taxonomy is the science of naming species and determining their relationships, and taxonomic studies have divided the Solanaceae into various natural groups of interrelated species. This study examined the species interrelationships within one of these natural groups, referred to as the potato clade. The potato clade contains about 200 of the 1500 Solanum species, including the economically very important and cosmopolitan crops potato and tomato, and a tree fruit grown more locally referred to as pepino. These crop species and their close relatives have been the focus of intensive research, but relationships among them has never been fully determined. This study uses the DNA sequences of various genes to explore relationships within the Potato clade. The results show it to be a good taxonomic group, and to contain 13 subgroups within it that we refer to as sections. We translate these DNA results into descriptions of these sections and provide a taxonomic key to them. This paper serves to unambiguously support the scientific validity of these section and to help describe them better for anyone needing information about them, such as plant breeders and conservationists.

Technical Abstract: With ca. 200 species, the informally named Potato clade represents one of the larger subgroups of the enormous genus Solanum. Because its members include the potato (Solanum tuberosum), tomato (S. lycopersicum), and pepino (S. muricatum), it is the most economically important clade in the genus. These crop species and their close relatives have been the focus of intensive research, but relationships among major lineages of the Potato clade remain poorly understood. In this study, we use sequences from the nuclear ITS and waxy (GBSSI) and plastid trnT–trnF and trnS–trnG to estimate a phylogeny and further explore relationships within the Potato clade. With increased sampling over past studies, the Potato clade emerges as a strongly supported clade and comprises 12–13 subclades which, for the most part, correspond to traditionally recognized sections. Solanum sect. Regmandra is sister to the rest of the lineages of the Potato clade which are, in turn, organized into two major subclades: (i) sections Herpystichum and Pteroidea, and (ii) sections Anarrhichomenum, Articulatum, Basarthrum, Etuberosum, Juglandifolia, Lycopersicoides, Lycopersicon, and Petota. As in all other studies including these groups, sections Etuberosum, Juglandifolia, Lycopersicoides, Lycopersicon, and Petota form a strongly supported clade. Solanum oxycoccoides, a high-elevation species endemic to north central Peru, was previously tentatively assigned to several groups within Solanum based on morphological evidence, but instead the species represents an independent lineage sister to the second major subclade. A key to the sections of the Potato clade is provided.