The origin and relationships of the pepino,Solanum muricatum (solanaceae): DNA restriction fragment evidence

Abstract

The pepino (or pepino dulce:Solanum muricatum) is a domesticate, of interest because of its close relationship to tomatoes and potatoes, because it is enjoying increasing exposure in the international market, and because it is a cultigen with no known wild ancestor. Morphologically this South American native is a member of the Solanum sect. Basarthrum, and as such, is allied to a number of Andean wild species. Data from other studies are combined with results from restriction site analysis of chloroplast and nuclear ribosomal DNA to assay relationships and 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 basendopogon (Peru),S. caripense (Costa Rica through Peru), S. tabanoense (Colombia and Ecuador)—emerge as most likely progenitors. Phylogenetic analyses of 61 accessions, including 27 of the pepino, dependent on chloroplast DNA (cpDNA) and nuclear ribosomal (rDNA) restriction site data show the pepino to be polymorphic, suggest independent origins for some of the cultivars, and most strongly supportS. tabanoense as the progenitor of the cultigen.Solanum caripense also may have been a direct ancestor of the pepino, or may have hybridized subsequent to its origin with the pepino to yield some of the haplotype variation. Similarly, S.cochoae may have hybridized with the pepino. There are no DNA characters supporting the involvement ofS. basendopogon in the origin.