Credited to Peru. The domestication zone around Lake Titicaca reaches into northwestern Bolivia, and the date is approximate.
How it began
Indigenous farmers in the Andes bred the cultivated potato from wild tuber-bearing relatives. The date is approximate. A USDA taxonomist who led a major genetic study says the earliest archaeological evidence points to domestication more than 7,000 years ago, while the FAO and others put it at about 8,000 years ago, in the high country around Lake Titicaca.
Where it happened was long disputed, and several separate origins were proposed. In 2005 a team led by David Spooner analyzed DNA markers in 261 wild and 98 cultivated potato types and concluded that all cultivated potatoes trace to a single origin in a broad area of southern Peru.
How it spread
After domestication the potato spread along the Andes and became a staple for Indigenous peoples including the Inca, partly as chuno, a freeze-dried form that keeps for years. After the Spanish invasion of 1532 tubers were carried across the Atlantic. The first plantings in Europe did poorly, because Andean varieties were used to 12-hour days and set tubers too late in the long northern summer.
The crop did better in Ireland after its introduction in the 1580s, and a century of farmer selection produced earlier varieties. From the British Isles it moved east: to the Low Countries by 1650, to Germany, Prussia and Poland by 1740, and to Russia by the 1840s.
Who pushed back
The potato took a long time to be accepted in Europe. Spaniards in South America regarded it as food for native laborers. In Europe it was at first grown as a curiosity or as fodder, and common accounts say people distrusted a plant of the nightshade family that grew underground. Open-field rules that allowed only grain also kept it out of large-scale cultivation in places.
Historians differ on who overcame this. The older account credits rulers and Enlightenment writers, such as Frederick the Great of Prussia, with persuading reluctant peasants. The historian Rebecca Earle argues that peasants had already adapted the crop themselves and that elites came to it later.
What changed first
For poor farmers the potato gave more food per acre than any grain, needed little cultivation and stored easily. In 17th and 18th century Ireland, one acre of potatoes and a milk cow could feed a family of six to eight. Because the tubers stayed underground and could be dug as needed, they were hard for tax collectors to assess and for passing armies to plunder. By the Napoleonic wars the potato had become Europe's food reserve.
What lasted
One widely cited economics study estimates that the potato accounts for about a quarter of the growth in Old World population and urbanization between 1700 and 1900. The historian William McNeill argued that by feeding fast-growing populations it helped a few European nations dominate much of the world between 1750 and 1950.
Dependence had a cost. In Ireland the potato supplied about 80 percent of calories from only a few varieties. When blight struck in 1845 to 1849, and the British government failed to respond adequately, about a million people died and a million emigrated.
Where it stands today
The potato is the world's fourth most important crop after rice, wheat and maize, and the leading producers are China, India, Russia and Ukraine. The International Potato Center, set up in Lima in 1971, keeps thousands of samples in its genebank. Breeders cross cultivated potatoes with some of the 151 known wild species to bring back disease resistance and tolerance of frost, drought and heat, which matters because one study projects that rising emissions could cut global yields by up to 26 percent by 2085. In Peru, the Potato Park near Cusco conserves native varieties in the field.
