THE ORIGIN AND RELATIONSHIPS OF THE PEPINO, SOLANUM-MURICATUM (SOLANACEAE) - DNA RESTRICTION FRAGMENT EVIDENCE

The pepino (or pepino dulce: Solanum muricatum) is a domesticate of in terest because of its close relationship to tomatoes and potatoes, bec ause it is enjoying increasing exposure in the international market, a nd because it is a cultigen with no known wild ancestor. Morphological ly this South American native is a member of the Solanum sect. Basarth rum, and as such, is allied to a number of Andean wild species. Darn f rom other studies are combined with results from restriction site anal ysis of chloroplast and nuclear ribosomal DNA to assay relationships a nd the potential origin of the pepino. The pepino may have existed in the wild previously and may be represented today only by the cultigen. However, if its ancestors are extant, three wild species-Solanum base ndopogon (Peru), S. caripense (Costa Rica through Peru), S. tabanoense (Colombia and Ecuador)-emerge ns most likely progenitors. Phylogeneti c analyses of 61 accessions, including 27 of the pepino, dependent on chloroplast DNA (cpDNA) and nuclear ribosomal (rDNA) restriction sire data show the pepino to be polymorphic, suggest independent origins fo r some of the cultivars, and most strongly support S. tabanoense as th e progenitor of the cultigen. Solanum caripense also may have been a d irect ancestor of the pepino, or may have hybridized subsequent to its origin with the pepino to yield some of the haplotype variation. Simi larly, S. cochoae may have hybridized with the pepino. There are no DN A characters supporting the involvement of S. basendopogon in the orig in.