JANSEN, ROBERT K.1*, GREGORY J. ANDERSON1, AND SUSAN CHEN1. 1Department of Botany, University of Texas, Austin, TX 78713 and 2Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269 - Origin and relationships of "Pepino" (Solanum muricatum) based on ITS sequence data.
Pepino, which is a close relative of tomatoes and potatoes, is cultivated in South America and New Zealand and is exported as an exotic fruit to up-scale markets in Europe, Japan, and the United States. The species is placed in Solanum section Basarthrum
along with 10 wild species. Previoius investigations using field studies, common garden analyses, morphological and chromosomal comparisons, and experimental crosses have suggested three possible wild progenitors, S. basendopogon, S. caripense, and S. tobanoense. Recent chloroplast DNA restriction site comparisons suggested that Pepino has had multiple origins, that pepino could be of hybrid origin, or that there has been recent hybridization between pepino and its putative progenitors subsequent to its origin. We have sequenced the ITS region of nuclear ribosomal DNA to assess relationships of Pepino to other species of section Basarthrum. The results indicate that S. basendopogon is not involved in the origin of Pepino, which is in agreement with cpDNA restriction site data. Furthermore, Pepino appears in multiple positions in the ITS tree, which is consistent with a multiple origin or a single origin and subsequent hybridization. Comparisons of the cpDNA and ITS data for the entire section Basarthrum indicate that trees from these two markers are largely congruent with regard to species relationships among the wild species.
Key words: Pepino, Solanaceae, Solanum muricatum