Taxonomy of Wild Potatoes in Northern South America (Solanum Section Petota)

Solanum section Petota, which includes the cultivated potato (S. tuberosum) and its wild relatives, is distributed from the southwestern United States to central Argentina, Uruguay, and adjacent Chile. This taxonomic treatment includes all wild species of section Petota from northern South America, which includes Venezuela, Colombia, Ecuador, and Peru. It is the last of five taxonomic treatments of a monophyletic potato + tomato + section Etuberosum clade, including treatments of 1) wild potatoes from North and Central America, 2) wild potatoes from southern South America, and the close outgroup section Etuberosum, 3) cultivated potatoes, and 4) wild tomatoes. Wild species of section Petota include diploids (2n = 24), triploids (2n = 36), tetraploids (2n = 48), and hexaploids (2n = 72), with all of these levels represented in northern South America. We here recognize 60 species from section Petota in this region and partition them into five species groups, recognizing only about half of the species from northern South America relative to the most recent taxonomic treatments by J. G. Hawkes and C. M. Ochoa. We summarize recent morphological and molecular studies of species limits and their interrelationships, and provide a key to the species, descriptions, synonymies (including designations of lectotypes), illustrations, localities, disease resistances, and distribution maps for all species.