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Telfairia pedata (Sm. ex Sims) Hook.

Protologue
Bot. Mag. 54: t. 2751–2752 (1827).
Family
Cucurbitaceae
Chromosome number
2n = 22
Vernacular names
Oyster nut, Queen’s nut, Zanzibar oil vine (En). Kouémé, bane, châtaigne de l’Inhambane, liane de Joliff (Fr). Castanha de Inhambane, sabina (Po). Mkweme, mkwema (Sw).
Origin and geographic distribution
Telfairia pedata is native to mainland Tanzania and northern Mozambique and the isles of Zanzibar and Pemba. It is cultivated in Central, East and southern Africa from Rwanda and Uganda to Ethiopia and southwards through Tanzania to Zambia, Malawi, Mozambique and South Africa. It has been grown in Madagascar and Mauritius, but there its importance has declined.
Uses
The seeds of Telfairia pedata are eaten raw, cooked or roasted and are said to taste as good as almonds or Brazil nuts. They are used in confectionery and are also pickled. In East Africa they are given to nursing mothers to improve lactation. The seed kernel contains an excellent edible oil, known as ‘oyster-nut oil’ or ‘koémé de Zanzibar’. It is useful in cosmetics and in soap and candle making. The oil is used as medicine for stomach troubles and rheumatism in East Africa. The Wachagga of Tanzania use the seed as tonic after childbirth. After oil extraction, the presscake makes valuable feed for livestock, being rich in protein.
Production and international trade
Oyster nut is an item of international trade, although the bulk of the produce is for home consumption and local trading. Data on production and trade of oyster nut are virtually non-existent.
Properties
The seed shell makes up 40% of the weight of the seed. The composition of 100 g oyster nut kernel is: water 3.5 g, protein 27 g, and fat 66 g. The oil from the kernel has a pleasant, slightly sweet taste. The fatty acid composition of the oil is: oleic acid 11.5%, linoleic acid 32.5%, linolenic acid 5%, palmitic acid 24.5% and stearic acid 18%. The seed has good keeping qualities and may keep for up to eight years and still remain in excellent condition when husked.
Description
Dioecious liana up to 30 m long; root system deep growing, thick, tuberous; stem initially herbaceous, ribbed, glabrous, climbing by bifid axillary tendrils, becoming woody with age and up to 10 cm in diameter; young branches glabrous and green. Leaves arranged spirally, pedately compound with 5–7 leaflets; stipules absent; petiole 2.5–10 cm long; leaflets with petiolules 1–6.5 cm long, central one largest, 5.5–14 cm × 2–7.5 cm, oblong to elliptical, acuminate, toothed especially in apical part, glabrous or slightly hairy on the main veins, lateral leaflets occasionally lobed at base. Inflorescence unisexual; male inflorescence an axillary lax raceme 6–23.5 cm long, bracts broadly ovate, 4–10 mm long, toothed, pubescent, adnate to the pedicels; female flowers solitary in leaf axils. Flowers 5-merous, pinkish purple, pedicel up to 14 cm long, receptacle campanulate, sepals triangular, 12–18 mm long, acute, pubescent and shortly laciniate, petals obovate, 2–3.5 cm long, crinkly, pinkish-purple fringed; male flowers with 3–5 free stamens; female flowers similar to male flowers, but slightly larger and with inferior, cylindrical, ribbed ovary. Fruit a drooping, ellipsoid berry, 30–90 cm × 15–25 cm, weighing up to15 kg, with a lobed expanded base and 10 blunt ribs, initially pale green but turning yellowish green at maturity, tardily dehiscent by 10 valves, many-seeded. Seeds oyster-shaped, flattened, 33–40 mm in diameter, 10–13 mm thick, enclosed in a fibrous, reticulate sheath. Seedling with epigeal germination.
Other botanical information
Telfairia is classified in the tribe Joliffieae of the subfamily Cucurbitoideae. It comprises 3 species, of which Telfairia occidentalis Hook.f. (fluted pumpkin) is grown in West Africa as a vegetable. In agricultural literature the 2 species are sometimes confused.
Growth and development
Seeds of oyster nut germinate 2–3 weeks after planting. Early growth is fast; plants can reach a length of 7 m in 6 months and 15 m in 18 months. Female and male plants cannot be distinguished until they flower. Flowering normally starts 15–18 months after planting and the first fruits ripen 4–6 months later. Under good conditions, 2 harvests per year are possible, and flowers and fruits can be present at the same time. Pollination is probably by insects, but apomictic seed production is likely. Under favourable conditions, plants remain productive for up to 20 years. When uncontrolled the lianas may overgrow 15–20 m tall trees and crush them by their weight.
Ecology
Telfairia pedata is found in lowland coastal and riverine forest at elevations of up to 1100 m in areas with mean annual rainfall of 1000 mm or more. In cultivation it is found up to 2000 m altitude, but at higher altitudes yields are distinctly lower. It thrives on well-drained medium loam soils and is drought-resistant.
Propagation and planting
Telfairia pedata is mostly propagated by seed. Seeds have short viability. Repeated soaking and drying promotes germination. In home gardens seeds are often planted directly along the drip line of large trees; for larger plantations nurseries are recommended. Vegetative propagation is effective using layering and cuttings, the latter being easily obtained by pruning. Stem cuttings root in 2–3 weeks and produce shoots 6–7 weeks after planting. Since oyster nut is dioecious, vegetative propagation will help avoid the preponderance of male plants as occurs naturally. Planting density of about 190 female plants per ha, plus 10–15 male plants per ha is required to obtain good pollination.
Management
Telfairia pedata has been grown commercially on 2 m tall trellises. These should be very strong and durable to support the massive weight of the vines. Trellises are spaced 3–4 m apart and plants about 15 m. Per plant 1–3 stems are left to develop. In home gardens young plants may be trellised until they reach the branches of supporting trees. Telfairia pedata is part of the rich agroforestry systems of Mount Meru and Mount Kilimanjaro in Tanzania, where it is grown in combination with coffee and banana.
Diseases and pests
Apart from general pests such as grasshoppers and termites, few diseases and pests have been recorded on Telfairia pedata. Cyst nematodes (Heterodera spp.) may attack the roots and the pentatomid shield bug (Piezosternum calidum) has caused serious damage in Uganda.
Harvesting
When fruits ripen they split open gradually. To attain full flavour, seeds should be allowed to ripen in the fruit and be collected a week to 10 days after the fruit begins to split.
Yield
Telfairia pedata produces 10–30 fruits in its third year. Good plantations can reach an annual seed yield of 3–7 t/ha.
Handling after harvest
To remove the bitter principle, whole seeds can be soaked for 8 hours in 3 changes of water. To remove the kernel from the shell, the fibrous husk is first partly cut away, then the shell is cracked and opened using a knife. One man can shell about 2 kg of seeds per hour. Mechanical decortication is also possible. Before oil extraction, the shell around the seed should be removed carefully as the presence of even a small amount imparts a bitter taste. The difficulty of completely removing the shell makes commercial extraction difficult.
Genetic resources
The area of natural distribution of Telfairia pedata is rather small, comprising eastern Tanzania and northern Mozambique. This may imply that natural populations can become liable to genetic erosion with ongoing habitat destruction. No germplasm collections are known to exist.
Prospects
Oyster nut is of economic importance in Central and East Africa on account of the seed. There was flourishing export market to Europe, but its current importance is unknown. Collection and evaluation of germplasm is urgently needed. Management of commercial plantations and post-harvest technology deserve research attention.
Major references
• FAO, 1988. Traditional food plants: a resource book for promoting the exploitation and consumption of food plants in arid, semi-arid and sub-humid lands of Eastern Africa. FAO food and nutrition paper 42. FAO, Rome, Italy. 593 pp.
• Jeffrey, C., 1978. Cucurbitaceae. In: Launert, E. (Editor). Flora Zambesiaca. Volume 4. Flora Zambesiaca Managing Committee, London, United Kingdom. pp. 414–499.
• Jeffrey, C., 1980. A review of the Cucurbitaceae. Botanical Journal of the Linnean Society 81: 233–247.
• Mnzava, N.A. & Bori, O.H., 1985. Seed germination and early seedling growth studies in the oyster-nut. Acta Horticulturae 158: 227–229.
• Okoli, B.E., 1988. Studies on fruit, seed morphology and anatomy in relation to the taxonomy of Telfairia Hooker (Cucurbitaceae). Feddes Repertorium 99(3-4): 133–137.
• Poppleton, W.J., 1939. The oyster nut, Telfairia pedata (native names: kwemme, jiconga). East African Agricultural Journal 5: 114–120.
• World Agroforestry Centre, undated. Agroforestree Database. [Internet] World Agroforestry Centre (ICRAF), Nairobi, Kenya. http://www.worldagroforestry.org/ Sites/TreeDBS/ aft.asp. Accessed January 2006.
Other references
• Goodchild, A.J.P., 1967. Shield bug (Piezosternum calidum Fab.) infestation of oyster nut. East African Agricultural and Forestry Journal 33: 192–196.
• Griesbach, J., 1992. A guide to propagation and cultivation of fruit-trees in Kenya. GTZ, Eschborn, Germany. 180 pp.
• Jamieson, G.S., 1938. The chemistry of the acyclic constituents of natural fats and oils. Annual Reviews of Biochemistry 7: 77–98.
• Jeffrey, C., 1967. Cucurbitaceae. In: Milne-Redhead, E. & Polhill, R.M. (Editors). Flora of Tropical East Africa. Crown Agents for Oversea Governments and Administrations, London, United Kingdom. 157 pp.
• Keraudren, M., 1966. Cucurbitacées (Cucurbitaceae). Flore de Madagascar et des Comores (plantes vasculaires), famille 185. Muséum National d’Histoire Naturelle, Paris, France. 173 pp.
• Keraudren-Aymonin, M., 1993. Cucurbitacées. In: Bosser, J., Cadet, T., Guého, J. & Marais, W. (Editors). Flore des Mascareignes. Familles 90–106. The Sugar Industry Research Institute, Mauritius, l’Institut Français de Recherche Scientifique pour le Développement en Coopération (ORSTOM), Paris, France & Royal Botanic Gardens, Kew, Richmond, United Kingdom. 22 pp.
• Okoli, B.E., 1987. Anatomical studies in the leaf and probract of Telfairia Hooker (Cucurbitaceae). Feddes Repertorium 98(3-4): 231–236.
• Okoli, B.E., 1987. Morphological and cytological studies on Telfairia Hooker (Cucurbitaceae). Feddes Repertorium 98(9-10): 505–508.
• Okoli, B.E., 1989. SEM study of surface characteristics of the vegetative and reproductive organs of Telfairia (Cucurbitaceae). Phytomorphology, 39(1): 103–108.
• Okoli, B.E. & McEuen, A.R., 1986. Calcium-containing crystals in Telfairia Hooker (Cucurbitaceae). New Phytologist 102: 199–207.
• O’Kting’ati, A., Maghembe, J.A., Fernandes, E.C.M. & Weaver, G.G., 1984. Plant species in the Kilimanjaro agroforestry system. Agroforestry Today 2: 177–186.
• Vaughan, J.G., 1970. The structure and utilization of oil seeds. Chapman & Hall, London, United Kingdom. 279 pp.
Sources of illustration
• Jeffrey, C., 1978. Cucurbitaceae. In: Launert, E. (Editor). Flora Zambesiaca. Volume 4. Flora Zambesiaca Managing Committee, London, United Kingdom. pp. 414–499.
Author(s)
B.E. Okoli
Regional Centre for Bioresources & Biotechnology, University of Port Harcourt, Port Harcourt, Nigeria


Editors
H.A.M. van der Vossen
Steenuil 18, 1606 CA Venhuizen, Netherlands
G.S. Mkamilo
Naliendele Agricultural Research Institute, P.O. Box 509, Mtwara, Tanzania
General editors
R.H.M.J. Lemmens
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
L.P.A. Oyen
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
Photo editor
A. de Ruijter
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands

Correct citation of this article:
Okoli, B.E., 2007. Telfairia pedata (Sm. ex Sims) Hook. In: van der Vossen, H.A.M. & Mkamilo, G.S. (Editors). PROTA 14: Vegetable oils/Oléagineux. [CD-Rom]. PROTA, Wageningen, Netherlands.
Distribution Map wild and planted


1, part of stem with male inflorescence; 2, part of stem with female flower; 3, fruit; 4, seed.
Redrawn and adapted by Iskak Syamsudin



crop in the field


fruit


seeds on the market