Potato is the starch tuber crop of Solanaceae. The word "potato" can refer to both the plant itself and the edible tuber. In the Andes, where the species is indigenous, there are other closely related cultivated potato species. About four centuries ago, potatoes were introduced outside the Andes and have since become an integral part of many of the world's food supplies. It is the fourth largest food crop in the world, after corn, wheat and rice. The green leaves and skin of tubers exposed to sunlight are toxic.
Wild potatoes can be found throughout the Americas, from the United States to southern Chile. At first, it was thought that potatoes were domesticated independently in many places, but later genetic tests on a variety of cultivated and wild species proved that potatoes are the only origin in southern Peru and northwest Bolivia (from a species in Solanaceae short eggplant complex, which was domesticated about 7000-10000 years ago). After hundreds of years of selective breeding, there are now more than 1000 different types of potatoes. At present, more than 99% of the world's Potato Cultivars come from the lowlands of south central Chile, which have replaced the previously popular varieties from the Andes.
However, the importance of potatoes in the local area is changing and changing rapidly. It is still an important crop in Europe (especially in eastern and central Europe), where per capita production is still the highest in the world, but the fastest growing regions in the past decades are South Asia and East Asia. Up to 2007, China's potato production ranked first in the world, and nearly one third of the world's potato production came from China and India.