Submitted to: Meeting Abstract
Publication Type: Abstract only
Publication Acceptance Date: 8/2/2007
Publication Date: 11/26/2007
Citation: Spooner, D.M., Ames, M., Ghislain, M. 2007. Evolution and classification of the cultivated potato [abstract]. II International Vavilov Conference Crop Genetic Resources in the 21st Century: Current Status, Problems and Prospects. Interpretive Summary:
Technical Abstract: The cultivated potato is one of the most important food plants worldwide, yet knowledge of the gene pool structure of the native South American landraces remains largely uninvestigated and has long been controversial. As a result, contrasting taxonomic treatments of the landraces have continued over last century, with the recognition of anywhere from one to twenty distinct Linnean species, or of various Cultivar Groups within the single species Solanum tuberosum. We provide one of the largest molecular marker studies of any crop landraces to date, to include an extensive study of 742 landraces of all cultivated species (or Cultivar Groups), and eight closely related wild species progenitors, with 50 nuclear microsatellite primer pairs and a plastid DNA deletion marker that typically distinguishes the Chilean from the Andean tetraploid landraces. Neighbor joining results highlight a tendency to separate three groups: 1) putative diploids, 2) putative tetraploids, and 3) the hybrid Cultivar Groups Ajanhuiri (diploid), Juzepczukii (triploid), and Curtilobum (pentaploid). However, there are many exceptions when clustering is performed ploidy and Cultivar Group. In combination with recent morphological analyses and an examination of the identification history of these collections, we conclude that only the Ajanhuiri, Juzepczukii, and Curtilobum Groups are well-defined. For the remaining accessions, consistent and stable identifications are impossible, their classification as Linnean species is artificial, and it only maintains confusion by the users, in genebanks, and in the literature. This classification much better interprets the morphological and genetic structure of the cultivated potato and will serve as a better predictive classification of the cultivated landraces in breeding programs.