Plant 140

Solanum tuberosum L. (Solanaceae)



The centre of potato diversity is in the Andes, with potatoes sustaining the Incan Empire for nearly four centuries before the arrival of Europeans. Solanum tuberosum appears to have been domesticated once, more than 5,000 years ago, from a wild Solanum species in the region of southern Peru and northwestern Bolivia. Millennia of selection by indigenous peoples transformed toxic wild tubers into thousands of cultivars with edible tubers varying in shape, colour, texture and cooking properties. Across South America, domesticated potato diversity has been split into ssp. tuberosum from the south-central Chilean lowlands and ssp. andigena from the Andean highlands.

Outside South America, the Spaniards first cultivated the potato in the Canary Islands in 1567; these islands became the potato's gateway into Europe. Some Europeans were early adopters of potatoes. In contrast, French potato culture is inextricably linked with the persuasive power and personality of the eighteenth-century chemist Antoine-Augustin Parmentier. He survived on potatoes as a prisoner of the Prussians, and when he returned to France he garnered scientific evidence of the nutritional qualities of potatoes. However, it was Parmentier's panache, guile and luck that changed French cuisine.

The South American origin of European potatoes has been debated for decades. Two hypotheses have been in competition. The prevailing hypothesis, over the last sixty years, has been the Andean hypothesis, where European potatoes were introduced from the northern Andes. The alternative, Chilean hypothesis, states that European potatoes were introduced from south-central Chile.

DNA analyses reveal extant Canarian potatoes are a mixture of tuberosum and andigena genetic types. Using DNA extracted from European potato specimens preserved in herbaria it has been shown that the tuberosum type appeared in Europe around 1700 and persisted until the end of the nineteenth century. The andigena type first appeared in Europe in 1811. Together these data support the Chilean hypothesis.

The history of the potato illustrates the vulnerability of crop plants to fungal pathogens when they only contain low levels of genetic variation. The mass dependency of the Irish poor on a single potato variety, the 'Irish Lumper', devastated the Irish population when late blight (Phytophthora infestans) arrived in Ireland in the mid-nineteenth century. The fungal infection had been accidentally introduced from the Americas to Europe in the early nineteenth century. The predominance of andigena genetic types in modern cultivars is thought to be a consequence of attempts to breed resistance to late blight into potatoes.

Further reading

Gomez-Alpizar L et al. 2007. An Andean origin of Phytophthora infestans inferred from mitochondrial and nuclear gene genealogies. Proceedings of the National Academy of Sciences USA 104: 3306-3311.

Reader J 2008. Propitious esculent: the potato in world history. William Heinemann.

Rios D et al. 2007. What Is the origin of the European potato? Evidence from Canary Island landraces. Crop Science 47: 1271-1280.

Stephen Harris