Food Plants International

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Names
English: White yam, White Guinea Yam Scientific name: Dioscorea rotundata Poir.
Tok pisin: Synonyms: Dioscorea cayenensis Lam.
Tok ples: Plant family: Dioscoreaceae
Description: 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 cultivars occur.
Distribution: 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.
Cultivation: 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.
Production: 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.
Use: The tubers are cooked and eaten.
Food Value: Per 100 g edible portion
Edible Moisture Energy Protein Calcium Iron proVit A proVit C Zinc
part % KJ g mg mg µg mg mg
Tuber 80.0 298 1.5 5.2 0.8 10 0.4
Insects:
Diseases:
Pests:
Importance:
The most important yam in West Africa. It has only recently been introduced to Papua New
Guinea.