Potato yam
Dioscorea bulbifera

Family: Dioscoreaceae

What it is like

A yam with a long smooth stemmed vine, round in cross section. It winds to the left. It does not have spines. The vine can climb up into trees and grow to long lengths. The leaves are large and round. They are pointed at the tip and round at the base. About 7 veins arise from the tip of the leaf stalk. Leaves can be 14-30 cm across and slightly longer than wide. This yam produces bulbils (potatoes) in the angles of the leaves along the vine. These are often flattened and can be grey brown or purple. Under the ground it has a smaller tuber normally covered with roots. The flowers are large. The male flowers are in spikes up to 20 cm long. The female spikes are usually in pairs. The fruit are winged and about 2.5 cm long by 1.5 cm across. The seeds have wings. The bulbils normally have few fibres through the tissue compared to some yams tubers. The flesh of many varieties is yellow.

There are about 650 species of Dioscorea. It can be invasive.

Where it is found

A tropical plant. It will grow from the coast up to about 1700 m altitude in equatorial zones. It is common near the edge of grassland and forest at mid altitudes. It grows in savannah woodland. Both wild and cultivated forms occur. It is common in the Philippines, Solomon Islands and Papua New Guinea near secondary forest at low and medium altitudes. It is cultivated in Africa and the West Indies. In Nepal it grows to 2100 m altitude. It suits hardiness zones 9-12. In Yunnan.

Countries/locations it is found in

Africa, American Samoa, Andamans, Angola, Asia, Australia, Bangladesh, Benin, Bhutan, Bolivia, Bougainville, Brazil, Burkina Faso, Burundi, Cambodia, Cameroon, Central Africa, Central African Republic, CAR, Central America, China, Christmas Island, Chuuk, Colombia, Comoros, Congo DR, Congo R, Cook Is., Costa Rica, Côte d'Ivoire, Chuuk, Cuba, Dominican Republic, East Africa, East Timor, Ecuador, Ethiopia, Fiji, French Polynesia, FSM, Gambia, Ghana, Guam, Guiana, Guianas, Guinea, Guinée, Guinea-Bissau, Haiti, Himalayas, India, Indochina, Indonesia, Ivory Coast, Jamaica, Japan, Kenya, Korea, Laos, Liberia, Madagascar, Malawi, Malaysia, Maldives, Mali, Marquesas, Mauritius, Micronesia, Myanmar, Namibia, Nepal, New Caledonia, Niger, Nigeria, Niue, North America, Northeastern India, Pacific, Pakistan, Palau, Papua New Guinea, Peru, Philippines, Puerto Rico, Reunion, Rotuma, Sahel, Samoa, Sao Tome and Principe, SE Asia, Senegal, Sierra Leone, Sikkim, Solomon Islands, Southern Africa, South America, Sri Lanka, St Lucia, Suriname, Tahiti, Taiwan, Thailand, Timor-Leste, Togo, Tonga, Tanzania, Uganda, USA, Vanuatu, Venezuela, Vietnam, Wallis & Futuna, West Africa, West Indies, Yap, Zambia, Zimbabwe

How it is used for food

The tubers are cooked and eaten. More commonly the aerial bulbils are eaten after cooking. Often the cooking water is changed a couple of times to remove bitterness. Some kinds are bitter and inedible or at least require special processing and cooking. Some varieties are poisonous. Some can cause act as contraceptives.

It is a commercially cultivated vegetable. This yam is widely distributed in lowland areas of Papua New Guinea and is a supplementary starchy staple food.

Edible parts

Tuber, root, bulbils, vegetable

How it is grown

Either the bulbils off the vine, or the underground tubers are planted. Because the vines are long, training them up trees is convenient. The bulbils have to be stored for a period of time before they will sprout. The plant is annual and leaves die off for 1-4 months each year before re-sprouting from the tuber. Bulbils only grow shoots from one end unless the bulbil is cut into pieces. If the larger bulbils are cut, the cut surfaces should be dried and healed in a shady place for 2-3 days before planting. Bulbils are planted 8-12 cm below the surface and spacing can be 100 cm by 100 cm or variations of this. Normally nitrogen and potassium fertilisers give greater responses than phosphorus. Friable well drained soils are most suitable. Often very little cultivation or mounding is done. A high level of organic matter improves yield. Staking is normally required but often trees or living stakes are used. Branched stakes 2 m high are suitable. They need to be strongly erected as vine and tuber growth can be extensive and heavy.

Bulbils or aerial yams are produced as soon as leaves begin to unfold and continue until the plant reaches maturity. These aerial tubers often fall from the plant. Harvesting can start 3 months after planting but immature tubers have less starch. Underground tubers are normally not harvested until the leaves die back. Wounds and damage to the tuber surface normally heals naturally given dry aerated conditions. Some varieties have aerial tubers which are seasonally dormant and only grow after an extended period of storage. Others germinate relatively quickly.

Its other names

Local names

Abubu, Acom, Aerial Yam, Agbanio, Ah-lu-thi, Air-potato, Akam, Ankindjek, Apuereka, Assidhakattala, Bachi, Ban tarul, Banalu, Bantarul, Ban temee, Barodaa, Basel phauk, Batata de rama, Bayag-toro, Bayal, Bejuco de natilla, Belloi, Bon-alu, Bontarul, Bubaia, Buefu, Cambare marron, Cara de are, Catoco, Chaxo poa, Chedu dumpa, Chedupaddu-dumpa, Cheeky yam, Chitangula, Chupri alu, Coolngarrie, Cu mei, Dai, Danda yam, Dandam, Dandandim-o, Dangkanda, Dau fasia, Dehs prei, Denebra, Dimoa, Drun, Dukkar-kand, Endome, Engin, Favi, Fikengere, Fui, Gaicha alu, Gaithi, Ganmanggu, Gasalu, Gathalu, Geetha, Genebra, Gethi, Gethia kanda, Ghartarul, Gidtha, Githi, Githa, Githo, Goch alu, Gosh alu, Gulgariny, Gunda, Haaran bo, Heggenasum, Helak, Ho, Hofikary, Hoi, Huang du, Huwi blichik, Indrenni, Igname bois, Igname-sau-vage, Inga piru, Iroga, Jebubug basu, Kadukand, Kadukaranda, Kadvokand, Kaile, Kaile dranu, Kaile manu, Kalangua, Ka la si, Kalialia, Karanda, Karukarinda, Karuvalli, Kasiena, Kattala, Kattu-kachil, Khoinga, Ki, Kodi, Kodikilangu, Koile mila, Konjo, Kuchung, Kurlama, Lac, Lahara, Lekut, Lindya, Litu, Lu gong lai biu, Mabuaia, Magnaheugo, Malakaka yapendalamu, Man nok, Manamund, Manyanya, Mas aloo, Mas alu, Matalu, Matara, Mataru, Methe aloo, Mithene, Mitho githa, Mpenga, Muwana, Name del aire, Name volador, Niambe-de-matom, Nika, Numwe, Ofaka, Ofa lei, Ogoko, Oi, Okoo, Otaheite yam, Pain, Palai, Pannukilangu, Papa aerea, Papa del aire, Papa voladora, Peng-khe, Pesta-alo, Pisimonaju, Piska sanga, Pitaalu, Puralu, Puri, Putsa-u, Ranmataru, Ratalu, Ratulu, Rok, Ruipan, Rukhel, Sang, Shunku papa, Sise, Soi, Soko, Suaralu, Syak, Te'e, Tewe,Tha borok, Thaphu miyung-wablai, Tikor alu, Timbom, Tito githa, To, Ubi atatus, Ubi-ubihan, Udala, Ufi lei, Uhi, Undome, Uwi gantung, Wila, Yi bao, Yoi

Synonyms

Dioscorea anthropophagorum A. Chev.; Dioscorea bubifera L. var. sativa (Thunb.) Prain; Dioscorea bulbifera var. anthropophagorum (A. Chev.) Summerh.; Dioscorea latifolia Benth.; Dioscorea sativa var. rotunda; Dioscorea sativa Thunb.; Helmia bulbifera (Linnaeus) Kunth.;