Yellow Yam, Yellow Guinea yam
Dioscorea cayennensis

Family: Dioscoreaceae

What it is like

Yellow Yam or Yellow Guinea Yam (Dioscorea cayenensis) is a spiny vine that can be 10 - 12 m long. The leaves are pale green and heart shaped. It is a commercially cultivated for its roots that have a rough outer skin and pale yellow flesh. It is cooked and eaten as vegetable. It can also be dried and milled to produce flour. Leaves are made into tea.

Dioscorea cayennensis is an evergreen Perennial Climber growing to 10 m (32ft) by 0.5 m (1ft 8in) at a fast rate. See above for USDA hardiness. It is hardy to UK zone 10. The flowers are pollinated by Wind, Insects. The plant is not self-fertile. Suitable for: light (sandy) and medium (loamy) soils and prefers well-drained soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils and can grow in very acid and very alkaline soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist soil.

Height (m): 10

Where it is found

Not known in a truly wild situation, having arisen in cultivation.

Western Africa - possibly Dahomey.

Conservation Status: This taxon has not yet been assessed.

Countries/locations it is found in

Africa, Antilles, Brazil, Central Africa, Central America, Colombia, Congo, Costa Rica, Côte d'Ivoire, Cuba, East Africa, Ethiopia, Ghana, Guiana, Guinea, Guinée, Guinea-Bissau, Guyana, Haiti, Ivory Coast, Jamaica, Madagascar, Mali, New Caledonia, Nigeria, Pacific, Panama, Puerto Rico, Senegal, Sierra Leone, South America, Suriname, Togo, Trinidad, Uganda, Vanuatu, Venezuela, West Africa, West Indies, Zambia,

How it is used

Food

Rating: 4

Root - cooked in various ways and eaten as a vegetable. A palatable flavour with a dry, mealy flesh. The roots are sometimes dried and milled to produce a flour for storing - this flour is then stirred into boiling water and kneaded to form a paste. The roots have a rough outer skin and a pale yellow flesh.The roots are up to 3kg in weight. The roots can contain up to 91% carbohydrate, the highest for any yam. Protein content is low, about 2.5%. A tea is made from the leaves.

Root: includes bulbs, corms, tubers, rhizomes etc.

Tea: the various herb teas that can be used in place of tea, plus the genuine article.

Medicine

Rating: 0

Other

Rating: 0

Other Uses: None known

Food Forest: Plants for Edible Forest Gardens and Food Forests.

How it is grown

A plant of the moist, lowland tropics. It grows best in areas where annual daytime temperatures are within the range 20 - 32°c, but can tolerate 12 - 40°c. Plants can be killed at temperatures of 9°c. It prefers a mean annual rainfall in the range 1,200 - 1,900mm, but tolerates 900 - 3,000mm. It prefers a dry season of 2 months or less. Succeeds in full sun and in moderate shade. For best yields, this species requires a deep, well-drained, sandy loam that is not liable to water-logging. Succeeds in relatively light sandy soils, though the soil needs to be very fertile otherwise yields can be low. Prefers a pH in the range 6 - 6.7, tolerating 5.3 - 8. Daylengths of more than 12 hours are preferred during the early growing season since this encourages vegetative growth; daylengths of less than 12 hours towards the end of the growing season will encourage tuber formation and development. Requiring a longer growing season than other yams, mature roots are formed in 9 - 12 months from planting. The tuber has a very brief resting period and does not store well. It is in fact best stored, if necessary, in the earth. The tubers are formed near the surface of the soil and can be carefully removed from the growing plant without disturbing it, allowing the plant to continue cropping for up to three years. The tubers can be dug up as required and a common practice is to expose one side of the tuber and to cut away the distal part for consumption leaving the upper part to regenerate; hence the name 'cut-and-come-again'. This practice may be repeated for upward of three years. Yields of 30 tonnes per hectare have been obtained in the Caribbean. There are some named varieties. Although occasionally monoecious, the plant is usually dioecious, therefore both male and female forms need to be grown if seed is required.

Propagating it: Seed - rarely produced, they are not normally used to propagate this species. Cuttings of tubers. Small tubers can be cut into 2 - 4 sections, larger ones into 6 - 8 sections. Each section should have 2 - 3 dormant buds. The cut tuber is often left in the sun for several hours to promote wound healing and reduce the risk of fungal infection.

Best place to grow:

Habit: Perennial Climber

Hardiness: 10-12

Growth: Fast

Soil: Light (sandy), medium

Shade: Semi-shade, no shade

Moisture: Moist

Things to keep in mind

Freshly cut tubers can cause skin irritation due to the presence of raphides, which are destroyed when the tubers are cooked.

Its other names

Local names

aerial yam air potato air-potato ban tarul bengo nari bhyakur bitter yam brotwurzel buk bulb-bearing yam cheeky yam diha dukarkanda dukkarkanda genthi ghar tyaur githa heggenusu hisaki hoei-oepas hoi huang yao zi huángyàozi igname bulbifère inhame kamfo kanthamul kaya pendazam khashyo khe kisi kukur tarul kunta genusu ofika oviala papa voladora pas phor potatisjams potato yam pousse en l'air ratalu sakkisak tarul teme varahi varahi kand varahi kanda varahi (rhizome) varahika?da yamswurzel ñame de gunda

Synonyms

Dioscorea colocasiifolia Dalz. Non Pax Dioscorea sativa Beatson.