| There are approximately two hundred wild Solanum species related to the common cultivated potato (Solanum tuberosum L.) ranging from the United States to southern Chile and adjacent Argentina. While interspecific hybridizations are common, many species do not cross in sympatry, despite apparently compatible ploidies and lack of stylar barriers. To understand the evolutionary history of sect. Petota, nuclear RFLP-based (nRFLP) phylogenetic reconstructions of thirty-seven Petota species were compared to factors known to affect hybridization, such as endosperm balance number (EBN), ploidy, and geographical barriers. The range of EBN, ploidy, series, and proposed genome designations of sect. Petota were sampled and nRFLP based phylogenies were constructed using parsimony and neighbor joining analyses. The resulting phylograms were subjected to statistical analyses, including Templeton tests and parametric bootstrapping.; Phylogenetic trees did not reflect EBN, ploidy, or genome designations and suggested that several independent evolutionary events are required to explain the distribution of these traits on the resulting trees. However, results correlated well with Hawkes' (1990) hypothesis that the present distribution of potato is a result of ancient species migrations between North and South America. |
