An international team of scientists has discovered a genetic mechanism which allows potato plants to develop tubers during the long days of spring and summer in northern latitudes. Wild potatoes, which originate in the Andes of South America, were brought to Europe by Spanish sailors in the late 16th century. Naturally occurring near the Equator, Andean potatoes develop tubers on days which are relatively shorter than those in high latitude summer. Newly discovered mutations in a single potato gene are likely to have contributed to the widespread success of the potato, which is the third most important food crop in the world today.