Potato, a common vegetable used as a staple food throughout the world. It is also called the white, or Irish, potato to distinguish it from an unrelated vegetable, the sweet potato. Although used chiefly as food for humans, potatoes sometimes are fed to livestock. They are also used for the manufacture of alcoholic beverages and starch.

The potato is native to the cool upper valleys of the Andes of Peru and nearby countries. Its name comes from batata, a South American Indian word originally applied to the sweet potato.

The leading potato-producing countries are shown in the accompanying graph. In the United States, the leading producers are Idaho and Washington. Other major producing states are North Dakota, Wisconsin, Colorado, Oregon, and Maine.

A potato is approximately 80 per cent water, 15 per cent carbohydrates, and 4 per cent protein. It is rich in vitamin C, niacin, and thiamine and contains small amounts of iron and phosphorus. The skin is a good source of fiber.

Whole potatoes are eaten boiled or baked. Sliced potatoes are fried to produce American (or German) fried potatoes, French fried potatoes, shoestring potatoes, and potato chips. Potatoes can also be dried and ground into flour for potato pancakes and potato bread.

The Potato Plant

The potato plant is related to the eggplant and tomato. It is a low-growing, branching perennial herb with weak stems. Each leaf is divided into five to nine oval leaflets. The foliage is somewhat hairy and sticky. The plant bears clusters of small white or purplish flowers. The fruit, an inedible green berry about ¾ inch (2 cm) in diameter, usually does not form in cultivated varieties.

The potatoes are large tubersfood-storing bodies that grow from the end of an underground stem, below the fibrous roots. Each tuber bears several buds (the eyes of the potato) from which new plants grow.

PotatoesPotatoes are large tubers that grow from the ends of underground stems.

The potato plant grows best in a cool climate, in soil that is well drained and rich in nitrogen. The seeds are cut pieces of tuber, each containing one or two eyes. The pieces are planted 12 to 18 inches (30 to 45 cm) apart in hilled rows 24 to 36 inches (60 to 90 cm) apart. The tubers form 40 to 50 days after planting and mature after 90 to 120 days. Potatoes are harvested in late summer or early autumn. They may be stored for several months before marketing.

The Colorado potato beetle, flea beetles, leafhoppers, and aphids attack potato foliage, and wireworms feed on the tubers. The potato plant is subject to viral, bacterial, protistan, and fungal diseases, such as (respectively) leaf roll, blackleg, late blight, and black scurf. Various pesticides are used to kill potato pests. Some varieties of potatoes have been developed that are resistant to certain diseases.

Varieties of Potatoes

About 100 varieties of potatoes are grown in the United States. They are divided into four categories: round white, long white, russet, and round red. The leading varieties of round whites are Kennebec and Katahdin. The leading russet is the Russet Burbank, developed in the 1870's by Luther Burbank. Important varieties of long whites include the Norchip and Norland; of round reds, the Red La Soda and Red Pontiac.

Each potatoEach potato bears several eyes from which new plants grow.

The potato was first cultivated about 10,000 years ago by South American Indians. Spanish explorers brought the potato to Europe in the 16th century. At first it was used mainly for livestock feed.

In the 1600's, the potato was introduced into North America from Europe. It did not become an important food crop until 1719, when Scotch-Irish settlers began potato production in New Hampshire.

In the 18th century the potato began to replace cereals in the diet of the poor. The failure of the potato crop (caused by late blight) in Ireland in 1845-46 resulted in a severe famine.

The potato is Solanum tuberosum of the nightshade family, Solanaceae.