PHYLOGENY OF WILD AND CULTIVATED SOLANUM SPECIES BASED ON NUCLEAR RESTRICTION FRAGMENT LENGTH POLYMORPHISMS (RFLPS)

Phylogenetic relationships between 14 wild and 3 cultivated Solanum species, including the European potato, Solanum tuberosum ssp. tuberosum, were inferred using DNA restriction fragment length polymorphisms (RFLPs) as discriminating characters. Phenetic trees were obtained based on distance matrices as well as on parsimony methods, which were not significantly altered either by the computational method used, or by the individual plant genotypes or RFLP markers chosen for the analysis. The reliability of the tree topologies was assessed and, as expected, it increased with the number of polymorphic restriction fragments scored. The individual genotypes within each species, the different species themselves, and the main branches of the trees were clearly separated from each other. The least reliable parts in the trees were the positions of closely related species within the main clusters. S. tuberosum spp. tuberosum formed one group closely related with S. tuberosum spp. andigena, S. stenotomum, and S. canasense. This was well separated from a second group formed by S. sparsipilum, berthaultii, kurtzianum, gourlayi, vernei, spegazzinii, chacoense, and megistacrolobum. Two further branches were formed by S. demissum and S. acaule, and by S. polyadenium, S. pinnatisectum, S. stoloniferum, and S. etuberosum. The phenetic trees presented here supported the description of relationships among Solanum species based on biosystematic studies, with the exception of the placement of S. chacoense and S. megistacrolobum. © 1990 Springer-Verlag.