A single domestication for potato based on multilocus amplified fragment length polymorphism genotyping

Abstract

The cultivated potato, Solanum tuberosum, ultimately traces its origin to Andean and Chilean landraces developed by pre-Colombian cultivators. These Andean landraces exhibit tremendous morphological and genetic diversity, and are distributed throughout the Andes, from western Venezuela to northern Argentina, and in southern Chile. The wild species progenitors of these landraces have long been in dispute, but all hypotheses center on a group of approximately 20 morphologically very similar tuber-bearing (Solanum section Petota) wild taxa referred to as the S. brevicaule complex, distributed from central Peru to northern Argentina. We present phylogenetic analyses based on the representative cladistic diversity of 362 individual wild (261) and landrace (98) members of potato (all tuber-bearing) and three outgroup non-tuber-bearing members of Solanum section Etuberosum, genotyped with 438 robust amplified fragment length polymorphisms. Our analyses are consistent with a hypothesis of a "northern" (Peru) and "southern" (Bolivia and Argentina) cladistic split for members of the S. brevicaule complex, and with the need for considerable reduction of species in the complex. In contrast to all prior hypotheses, our data support a monophyletic origin of the landrace cultivars from the northern component of this complex in Peru, rather than from multiple independent origins from various northern and southern members.

Fig. 1.

Strict consensus parsimony cladogram of 10,000 equally parsimonious 13,176-step Wagner trees based on the entire AFLP data set of 362 accessions, with six AFLP primer combinations producing 438 characters. Outgroups consist of three accessions in Solanum section Etuberosum and clades 1-3 tuber-bearing wild potatoes (section Petota) (26). The remaining ingroup consists of members of clade 4, labeled as the northern and southern S. brevicaule groups and cultivated species. The southern S. brevicaule group includes species from North and Central America and species from South America that have not traditionally been considered part of this group. For space considerations, the taxa are staggered on the tree. Diploid accessions are colored black, tetraploid accessions are blue, and hexaploid accessions are red.

Fig. 1.

Strict consensus parsimony cladogram of 10,000 equally parsimonious 13,176-step Wagner trees based on the entire AFLP data set of 362 accessions, with six AFLP primer combinations producing 438 characters. Outgroups consist of three accessions in Solanum section Etuberosum and clades 1-3 tuber-bearing wild potatoes (section Petota) (26). The remaining ingroup consists of members of clade 4, labeled as the northern and southern S. brevicaule groups and cultivated species. The southern S. brevicaule group includes species from North and Central America and species from South America that have not traditionally been considered part of this group. For space considerations, the taxa are staggered on the tree. Diploid accessions are colored black, tetraploid accessions are blue, and hexaploid accessions are red.