White Guinea Yam
Dioscorea cayennensis subsp. rotundata

Family: Dioscoreaceae

What it is like

A climbing yam plant. The stems are round and can be 10-12 m long. They twine to the right around sticks. The stems are usually spiny, but can be smooth. There is a white bloom on the stems. The leaves are opposite and simple. They are 10-12 cm long by 6-8 cm wide. They are heart shaped and taper to a point. They are normally dark green and glossy. Some forms have leafy outgrowths (stipules) at the base of the leaf stalks. The flowers are often in groups of 4 and are formed near the leaves. It is mostly male flowers which occur and seeds are rarely produced. The tubers vary in shape, size and texture. Mostly they are like cylinders with rounded or pointed ends. The skin is smooth and brown with white flesh. The tubers can also be distorted in shape. Mostly only one tuber forms and the top end of the tuber is woody. A large number of different cultivated varieties occur.

There are about 650 species of Dioscorea. Many prefer to keep this as a separate species.

Where it is found

A tropical plant. It grows in places with a distinct dry season. Tubers have a time of dormancy. It can tolerate drought more than Greater yam (Dioscorea alata). It suits relatively heavy soils with a reasonable clay content. Rainfall of 1000-1500 mm distributed over 8-10 months is suitable.

Countries/locations it is found in

Africa, Asia, Benin, Bougainville, Brazil, Central America, Costa Rica, Côte d'Ivoire, East Africa, Ghana, Guinea, Guinée, Haiti, India, Ivory Coast, Jamaica, Kenya, Martinique, New Caledonia, Nigeria, Northeastern India, Pacific, Papua New Guinea, Philippines, Puerto Rico, SE Asia, Senegal, Sierra Leone, Sikkim, South America, St. Vincent and Grenadines, Togo, Vanuatu, West Africa, West Indies, Zambia

How it is used for food

The tubers are cooked and eaten.

It is a commercially cultivated vegetable. The most important yam in West Africa. It has only recently been introduced to Papua New Guinea.

Edible parts

Tubers, root, vegetable

How it is grown

Mostly setts of tubers are used. Occasionally seeds are used. Plants can also be grown from cuttings. About 1 sq metre per plant is suitable.

Crops last 8-10 months. Tubers can be stored for several months. Tubers normally weigh 2-5 kg but can be up to 10 kg weight. Yields of 16-20 t/ha are normal. Tubers should not be stored below 15°C as chilling injury can result.

Its other names

Local names

Citu, Eboe yam, Eight month yam, Ghar taru, He, Ishu, Njambwa, Round white yam, White yam, Yanwaa

Synonyms

Dioscorea rotundata Poir.;