Andrew F. Smith - Potato: A Global History

The traditional view of human settlement in the Americas is that indigenous peoples crossed the Bering Straits 16,000 years ago and moved rapidly down the west coast of the Americas, reaching Monte Verde in southern Chile about 14,000 years ago. These early Americans were hunters and gatherers, and they were sustained by a vast variety of edible wild plants. Among these were 235 different species of potatoes, which inhabited a wide expanse of territory encompassing most of South America as well as Central America and the American Southwest. Of all the domesticated food plants in the world today, none boasts as large a group of wild ancestors as the potato.

The western coast of South America has a narrow desert intersected by valleys carved out by rivers originating a short distance away, in the Andes, one of the worlds longest and highest mountain ranges. The eastern side of the Andes gradually slopes into dense tropical rainforests. Within this fragmented geography, numerous microclimates and a wide range of environments can be found, from deserts and fertile river valleys to jungles and glaciers.

The Andes have little flat land or fertile soil, but indigenous farmers terraced mountainsides, constructed irrigationditches and domesticated an estimated seventy plants almost as many plants as were domesticated in all of Europe or Asia. Twenty-five were tuber or root crops, such as the peppery-tasting au or mashua (Tropaeolum tuberosum), the radish-like maca (Lepidium meyenii), the brightly coloured oca (Oxalis tuberosa) and the ulluco (Ullucus tuberosus), as well as seven potato species, the most important being Solanum tuberosum. Many root plants are still grown commercially in South America today, but only one, S. tuberosum the common potato was catapulted from obscurity to global importance.

Domestication of S. tuberosum was likely accomplished around 10,000 BCE by Andean farmers, probably in the Lake Titicaca basin. In one of the worlds most inhospitable terrains for agriculture, the potato became the chief food of the people. The potato was well suited to the warm days of summer, which encouraged the growth of the above-ground plant, and the cold nights encouraged the growth of the tuber. Through trial and error, Andean farmers concluded that potatoes could be propagated by seed or by planting sprouts from its tubers. Not all potato plants produce seed balls, which are about the size of a cherry tomato. Growing plants from seeds produced a vast array of shapes, colours, sizes and tastes, but when a farmer found a type of potato he liked, he perpetuated the strain by planting the tubers, which are clones of the original plant. In this way, pre-Columbian peoples grew about 200 varieties of potatoes, and thousands more have been subsequently developed, making potatoes one of the worlds most diverse domesticated crops.