The sweet potato is a dicotyledonous plant that belongs to the morning glory family, Convolvulaceae. Its large, starchy, sweet- tasting, tuberous roots are a vegetable root. The leaves and young shoots are sometimes eaten as greens. The sweet potato is only distantly related to the potato (Solanum tuberosum) and does not belong to the moray eel family, Solanaceae, but both families belong to the same taxonomic order, the Solanales.
The plant does not tolerate frost. It grows best at an average temperature of 75 ° F (24 ° C), abundant sunshine, and warm nights. Annual rainfall of 750-1,000 mm (30-39 in) is considered the most suitable, with a minimum of 500 mm (20 in) in the growing season. The crop is sensitive to drought in the tuber initiation stage 50-60 days after sowing and does not tolerate logging of water as it can cause rot of tubers and reduce the growth of storage roots if the aeration is poor.
Depending on the cultivar and conditions, the tuberous roots mature in two to nine months. With care, early-maturing cultivars can be grown as a summer annual crop in temperate areas, such as the northern United States. Sweet potatoes rarely flower when daylight is longer than 11 hours, as is normal outside the tropics. They are mostly spread by stems or roots or by adventitious shoots called "slips" that grow from the tuberous roots during storage. True seeds are used for breeding only.
The Center for Science in the Public Interest ranked the nutritional value of sweet potatoes as the highest among several other foods.
Sweet potato cultivars with dark orange flesh have more beta-carotene than those with light flesh, and its growing cultivation is being encouraged in Africa where vitamin A deficiency is a serious health problem. A 2012 study of 10,000 households in Uganda found that children who ate beta-carotene-fortified sweet potatoes were less deficient in vitamin A than those who did not consume as much beta-carotene.
