Taxonomy of Wild Potatoes and their Relatives in Southern South America (Solanum sect. Petota, sect. Etuberosum)

SPOONER D. M.; CLAUSEN A.; PERALTA I. E.; ALVAREZ N.

The American Society of Plant Taxonomists

Lugar: MICHIGAN; Año: 2009 p. 500

ABSTRACT. Solanum section Petota, which includes the cultivated potato (Solanum tuberosum) and its wild relatives, is distributed from the southwestern United States to central Argentina, Uruguay, and adjacent Chile. Section Etuberosum, a closely related outgroup, is distributed in Argentina and Chile. Our taxonomic treatment includes all species of these two sections from southern South America (Argentina, Bolivia, Brazil, Chile, Paraguay, and Uruguay). Section Etuberosum is entirely diploid (2n = 2x = 24) and sect. Petota includes diploids (2n = 2x = 24), triploids (2n = 3x = 36), tetraploids (2n = 4x = 48), and hexaploids (2n = 6x = 72). The field component of our study yielded herbarium specimens and germplasm samples from all countries harboring wild potatoes in this region. We here recognize three species from sect. Etuberosum and 26 species from sect. Petota, and divide the latter into five informal species groups. Relative to the most recent comprehensive treatment of these species by Hawkes in 1990 we synonymized southern South American names of 36 species, seven subspecies, and one variety, and raised one subspecies to species rank; our treatment, therefore, recognizes only 40% of the taxa from Hawkes 1990 treatment. We identified major range expansions for S. acaule and S. medians in Chile. We present a summary of recent morphological and molecular studies of species limits and their interrelationships, descriptions, synonymies (including designations of lectotypes), species illustrations, localities, and distribution maps.