One of the world’s great botanical mysteries
Sweet Potato (Ipomoea batata or American yam) is a perennial vine of the convolvulacea family, growing to about 4m in moist soil and native to tropical America. The climbers display alternate heart shaped or palmately lobed leaves, with pale lilac trumpet flowers. The edible part is the root or tuber, which may range in colour from deep purple to red, brown and white, the flesh will be orange, white, brown or purple. The plant is one of the world’s staples and has been cultivated in south and central America for over 5,000 years. It is marketed in the US as a yam, but it has no connection with the Diosorea family, nor is it related to the common potato, Solanum tuberosum. The use of the word yam is thought to derive from the African slaves that called the vegetable ‘nyamis’, believing it to be a true yam. The plant is now grown throughout the world’s tropical and warm temperate regions.
Sweet potato has given rise to one of the great botanical mysteries; how did the plant, which was only known to grow in tropical America, become a staple food of the Pacific islanders, long before the advent of ocean travel. In 1947, the Norwegian adventurer Thor Heyerdahl suggested that the presence of sweet potatoes in Polynesia provided irrefutable evidence that the islands were settled by Amerindians. The cultivar found in Polynesia is exactly the same as the one cultivated in ancient Peru. The theory previously held, that the roots had travelled to the region on ocean currents, was dispelled when it was revealed that sweet potato cannot withstand seawater. Further evidence to support this premise was supplied by philologists who pointed out that the word for sweet potato in Polynesia, ‘kumara,’ is the same as that used by the Amerindian tribes. It was to prove his theory that Heyerdahl undertook his now famous voyage in the Kon-Tiki (which was built from Peruvian balsa wood), sailing without any navigation aids for 101 days from Lima to Tuamoto, just south of Tahiti.
Sweet potato contains carbohydrates, proteins, vitamins A, C and B6 as well as iron and calcium. It is rated as one of the most nutritional vegetables in the world. Medicinally, it has been used to treat diabetes, hookworm, internal bleeding and jungle ulcers; the uncooked roots are grated and eaten as a cure for asthma.
China is now the largest grower, producing over 130 million tons a year, providing over 80 per cent of the world’s requirements, the majority of this yield is for pigs. At one time sweet potato formed a substantial part of the diet of the southern states, particularly during slavery, but now is identified with a ‘poor man’s food’ and no longer eaten by the majority.
Sweet potato, which is popular in Cyprus at festive times, may be candied, baked in pies, steamed or boiled, cut into wedges and baked, or served like chips. The plant also yields a dye, which ranges from pink to purple.
It is grown in our region; Israel and Egypt being the main producers. There is no reason why it cannot be cultivated here.
Next week Sugar Palm
