CONICET | Buscador de Institutos y Recursos Humanos

The Solanum brevicaule complex is a group of about 20 wild potato (sect. Petota) species, with about 30 taxa with included varieties and subspecies, containing diploids (2n = 2x =24), tetraploids (2n = 4x = 48) and hexaploids (2n = 6x = 72), distributed from Peru south to central Argentina. The complex is defined entirely by morphological similarity of its constituent members, that are very similar to each other and to some landraces of the cultivated potato, Solanum tuberosum. Hybridization may be common among the species, and conflicting taxonomic treatments are common among authors. Species boundaries within the complex have been studied with morphological phenetics from germplasm accessions planted in a field plot in the north central United States (45°N, 180 m elevation), and with molecular marker data from RAPDs, low-copy nuclear RFLPs, and AFLPs. The present study compares these results with two additional replicated morphological studies of the same germplasm accessions in a greenhouse environment the high Andes of central Peru (12°S, 3200 m), in a field plot at the base of the Andes of west-central Argentina (33°S, 920 m). Correlation coefficients among all three morphological studies are low (0.29-0.32), and higher among molecular marker data sets (0.54-0.76). The results from the US and Peruvian (but not Argentinean) morphological data were similar in supporting three groups of species: (1) the northern S. brevicaule complex taxa from Peru and adjacent northwestern Bolivia, (2) the southern S. brevicaule complex taxa from Bolivia to Argentina, and (3) S. oplocense, with the cultivars of S. tuberosum clustered adjacent to the northern complex. There is poor support for species clustering within the northern and southern groups, suggesting the need for reduction of species in the complex.