Potato, Irish
A plant of the genus Solanum in the nightshade family, Solanaceae; it is related to tomatoes and peppers. There are more than 2000 species of Solanum, of which about 150 bear tubers. The potato of commerce, S. tuberosum, originated in South America, probably in the highlands of Peru and Bolivia, where it has been cultivated for several thousand years. Potatoes were introduced into Europe by Spanish explorers in the late sixteenth century and into the United States from Ireland in 1719. The crop became a staple in Europe, was a primary source of food in Ireland, and is known even today as the Irish potato. See also Solanales.
The potato plant is an annual, herbaceous dicotyledon that is grown primarily for its edible tubers, which are short, thick underground stems that form on the ends of stolons (lateral stems). Lateral buds (eyes) on the mature tuber are the growing points for a new crop, provided that whole tubers or pieces with at least one eye are planted.
There are 95–100 varieties certified for seed production in the United States and Canada. In the United States, seven varieties account for more than 70% of the commercial acreage planted. These are Russet Burbank, Norchip, Atlantic, Russet Norkotah, Superior, Centennial Russet, and Kennebec.
Potatoes are grown in more countries than any crop except for corn (maize), and they are the fourth-most important food crop in supplying energy in the human diet, following rice, wheat, and corn. The leading potato producers are Russia, China, Poland, and the United States, in descending order.
Chemical constituents can be affected by variety, production area, cultural practices, maturity at harvest, and storage conditions. The average composition of potatoes is 78–water% 80, 14–18% starch, 2% protein, 1% minerals, 0.4% fiber, and 0.1% fat, with some sugars, organic acids, amino acids, and vitamins. The potato is very nutritious, serving as a nearly complete food itself, and it produces more food per acre than any other crop. Starch constitutes about 65–80% of the dry weight of the potato and, calorically, is the most important component. Potatoes contain appreciable amounts of the B vitamins, and they are an excellent source of vitamin D. Potatoes contribute more vitamin C to the United States food supply than any other single food source. Inorganic constituents or minerals of potatoes are predominantly potassium, phosphorus, sulfur, chlorine, magnesium, and calcium. Potatoes contain sufficient quantities of iron to be a good nutritional source of this mineral as well.
