Potato (Solanum etuberosum)

Description

The potato is a starchy, tuberous crop from the perennial nightshade Solanum tuberosum. The word "potato" may refer either to the plant itself or to the edible tuber. In the Andes, where the species is indigenous, some other closely related species are cultivated. Potatoes were introduced to Europe in the second half of the 16th century by the Spanish. Potato has become a staple food in many parts of the world and an integral part of much of the world's food supply. It is the world's fourth-largest food crop, following maize, wheat, and rice. The green leaves and green skins of tubers exposed to the light are toxic. Wild potato species can be found throughout the Americas from the United States to southern Chile. The potato was originally believed to have been domesticated independently in multiple locations, but later genetic testing of the wide variety of cultivars and wild species proved a single origin for potatoes in the area of present-day southern Peru and extreme northwestern Bolivia (from a species in the Solanum brevicaule complex), where they were domesticated approximately 7,000–10,000 years ago. Following millennia of selective breeding, there are now over a thousand different types of potatoes. Over 99% of the presently cultivated potatoes worldwide descended from varieties that originated in the lowlands of south-central Chile, which have displaced formerly popular varieties from the Andes. However, the local importance of the potato is variable and changing rapidly. As of 2014, China led the world in potato production, and, together with India, produced 37% of the world's potatoes. Potato plants are herbaceous perennials that grow about 60 cm (24 in) high, depending on variety, with the leaves dying back after flowering, fruiting and tuber formation. They bear white, pink, red, blue, or purple flowers with yellow stamens. In general, the tubers of varieties with white flowers have white skins, while those of varieties with colored flowers tend to have pinkish skins. Potatoes are mostly cross-pollinated by insects such as bumblebees, which carry pollen from other potato plants, though a substantial amount of self-fertilizing occurs as well. Tubers form in response to decreasing day length, although this tendency has been minimized in commercial varieties. After flowering, potato plants produce small green fruits that resemble green cherry tomatoes, each containing about 300 seeds. Like all parts of the plant except the tubers, the fruit contain the toxic alkaloid solanine and are therefore unsuitable for consumption.