ARS | Publication request: Ecogeography of ploidy variation in cultivated potato (Solanum sect. Petota)

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: December 10, 2010
Publication Date: December 14, 2010
Citation: Spooner, D.M. 2010. Ecogeography of ploidy variation in cultivated potato (Solanum sect. Petota) [abstract]. Potato Genetics Technical Committe.

Technical Abstract: The taxonomy of cultivated potatoes has been highly controversial, with estimates of species numbers ranging from 3 to 17. Ploidy level has been one of the most important taxonomic characters to recognize cultivated potato species, containing diploid (2 n = 2 x = 24), triploid (2 n = 3 x = 36), tetraploid (2 n = 4 x = 48), and pentaploid (2 n = 5 x = 60) cultivars. We tested the environmental associations of different ploidy levels in cultivated potato species that traditionally have been recognized as Linnaean taxa to see whether, in combination with prior morphological, molecular, and crossing data, some of the ploidy variants can be recognized as distinct taxa. We summarized 2780 chromosome counts of landrace cultivated potatoes, provided georeferences to 2048 of them, and analyzed these data for 20 environmental variables at 10-min resolution using the randomForest algorithm to explore associations with taxa and ploidy variants. Except for the S. tuberosum Chilotanum Group and extreme northern and southern range extensions of the Andigenum Group, it is impossible to fi nd distinct habitats for the ploidy variants of the S. tuberosum Andigenum Group. Our distributional and ecological data, in combination with prior results from morphology, microsatellites, and crossing data, provide yet additional data to support a major reclassifi cation of cultivated potato species. A rational, stable, and universally accepted taxonomy of this major crop plant will greatly aid all users of wild and cultivated potatoes from breeders to gene bank managers to ecologists and evolutionary biologists.