Changes in the Potato Family Tree

Scientists from the US Agricultural Research Service (ARS) and the International Potato Center (CIP) have shown that there is actually four potato species instead of the previously postulated seven. The researchers used molecular markers in combination with morphological characteristics to come up with the new potato species designation. The four species are: the widely cultivated potato Solanum tuberosum, and the less common species S. ajanhuiri, S. juzepczukii and S. curtilobum.

Led by Marc Ghislain and David Spooner, the group screened 742 cultivated potato varieties and 8 wild potato relatives for the presence of a particular DNA mutation which distinguishes between the potatoes from the Andes and those from the Chilean lowlands.  Results of the study demonstrated that morphological variations among cultivated potatoes were not reliable indicators of species. The new system of species designation eliminates much of the guesswork that previously served as the foundation for the potato classification system.

Read more at http://www.ars.usda.gov/News/docs.htm?docid=1261