Submitted to: Supplement to American Journal of Botany
Publication Type: Abstract only
Publication Acceptance Date: 8/6/1996
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: Solanum L. sect. Petota Dumort., the potato and its wild relatives, contains about 200 tuber-bearing species distributed from the southwestern United States to southern Chile. Chloroplast DNA (cpDNA) restriction-site data defines four clades for the tuber- bearing species, with tomatoes (Solanum sect. Lycopersicum) as a sister clade, and Solanum sect. Etuberosum sister to both of these. Resolution is low within some clades, with many species forming large polychotomies. Sequence data from the two Internal Transcribed Spacers of nuclear ribosomal DNA (ITS1, ITS2) was used to reevaluate these clades with an independent molecular marker, and to attempt further resolution within clades. Higher level relationships from preliminary data including representatives of most clades, and outgroups in sections Lycopersicum and Etuberosum conform to most aspects of phylogenies from cpDNA restriction site data. Moreover, resolution within clades is greatly improved. These results show the utility of ITS sequence data for investigating higher- level cladistic relationships within sect. Petota and close relatives, and demonstrate sufficient variation in ITS data to resolve relationships among closely related species.