Solanecio biafrae (PROTA)

Plant Resources of Tropical Africa Introduction

List of species

General importance
Geographic coverage Africa
Geographic coverage World
Vegetable
Medicinal
Food security

Solanecio biafrae (Oliv. & Hiern) C.Jeffrey

Protologue: Kew Bull. 41(4): 922 (1986).

Family: Asteraceae (Compositae)

Chromosome number: 2n = 20

Synonyms

Senecio biafrae Oliv. & Hiern (1877), Crassocephalum biafrae (Oliv. & Hiern) S.Moore (1912).

Vernacular names

Worowo, bologi (En). Worowo (Fr).

Origin and geographic distribution

Solanecio biafrae occurs naturally in the forest zone from Guinea to Uganda. It is cultivated on a small scale only, mainly in Nigeria and Cameroon.

Uses

Fresh succulent leaves of worowo are used as a leafy vegetable in Sierra Leone, Ghana, Benin, Nigeria, Cameroon and Gabon. They are especially popular in south-western Nigeria. They are usually cooked with pepper, tomato and onions. In such dishes there is no need for meat or fish because of the excellent properties of the vegetable, reflected in the Yoruba proverb ‘vegetable soup prepared with worowo does not need meat’. However, fish or meat may be added to the soup. In Sierra Leone, where it is called ‘bologi’, the leaves are eaten as a steamed vegetable in combination with okra and fish. They are first steamed in boiling water and later squeezed to remove the mucilage from the leaves. The squeezing is followed by 2–3 rinses with cold water to remove the mucilage as completely as possible. An infusion of the leaves is taken as a drink. Among the Yoruba speaking people of south-western Nigeria, a leaf extract of worowo is used to stop bleeding from cuts or injury and in Sierra Leone and Cameroon a leaf extract is used to treat sore eyes. In Côte d’Ivoire pulped leaves are applied to the breasts as a galactagogue. In Congo worowo is used to treat cough and heart troubles, as a tonic and to relieve rheumatic pain, prurient allergies and localized oedemas. In Congo it also has cultural uses in initiation and funeral rituals and in Yoruba culture it is associated with rituals to ward off smallpox.

Production and international trade

Worowo is marketed only locally. There are no records of international trade. This vegetable is becoming quite rare and is therefore several times more expensive than Amaranthus, Celosia or Corchorus leaves.

Properties

In south-western Nigeria Solanecio biafrae occurs in two distinct types: plants with purple stems and plants with green stems. Leaves of the green-stemmed types contain per 100 g dry matter: crude protein 12.3 g, crude fibre 11.8 g, Ca 342 mg, P 39 mg, Fe 52 mg. Leaves of purple-stemmed types contain per 100 g dry matter: crude protein 11.6 g, crude fibre 10.5 g, Ca 320 mg, P 46 mg, Fe 53 mg (Adebooye, O.C., 2000). The leaves of Solanecio biafrae contain small amounts (less than 0.1 g/100 g fresh leaves) of terpenoids, mainly the sesquiterpene germacrene D.

Adulterations and substitutes

When worowo is not available, it can be replaced by other leafy vegetables, but they all taste different.

Description

Perennial climbing herb, with stem up to 3 m long, strongly branched; branches succulent, glabrous. Leaves alternate, simple or deeply pinnately lobed, more or less succulent; stipules absent; petiole 1–8(–10) cm long; blade triangular to hastate or with up to 3 lobes on each side, 5–15 cm × 3–14 cm, margin sparsely toothed, surface glossy. Inflorescence a narrowly campanulate head 9–12 mm × 3–5 mm, arranged in a terminal, compound, dense corymb; head many-flowered, homogamous; peduncle 5–11 cm long; involucral bracts 4–6. Flowers bisexual, tubular, 5-merous; corolla c. 6 mm long, pale yellow; stamens with fused anthers; ovary inferior, 1-celled, style bifid. Fruit a cylindrical, glabrous achene c. 3 mm long, black when ripe, with pappus consisting of long, white, silky hairs.

Other botanical information

Solanecio comprises about 16 species and occurs in tropical Africa, Madagascar and Yemen. It belongs to the tribe Senecioneae and seems related to Gynura, which is not succulent.

Leaves of Solanecio angulatus (Vahl) C.Jeffrey are also collected from the wild and used as a cooked vegetable in DR Congo, but it is mainly used for medicinal purposes. The leaves of Solanecio angulatus are usually pinnately lobed and its fruits are hairy.

Growth and development

Solanecio biafrae is a climber that twines clockwise on woody plants. Profuse branching occurs about 50 cm above the ground causing bushy growth. The stems are very tender and break easily even when handled with care. Flowering takes place in Nigeria in January–February. Worowo continues to grow in the dry season under the moist conditions of cacao plantations.

Ecology

Solanecio biafrae is an understorey climber in the rainforest zone of West and Central Africa, where average annual rainfall is about 1500 mm, from sea-level to 1300 m altitude. It strongly responds to water stress by developing shrivelled stems and yellowing of the leaves, and cannot survive under dry conditions. In cultivation provision of shade is essential for good growth. It prefers a moist, well-drained soil rich in organic matter.

Propagation and planting

Worowo is generally collected from the wild, but is occasionally cultivated. Seed production is abundant and propagation by seed is possible, but viability tends to be very poor (generally < 2%). Moreover, the seed is difficult to clean because of the pappus. The weight of 1000 seeds is about 0.5 g. Seed should be planted in pervious humid soil under light shade. Germination takes several days. Spontaneous seedlings are sometimes collected for transplanting. For vegetative propagation semi-hard cuttings of 10–15(–30) cm long with 4–6 nodes are used. It is recommended to remove the leaves and tops before planting. Cuttings are planted in moist well-drained soil rich in organic matter and always under a tree or shrub for shade and support. There is no need for a nursery. Plants require a spacing of 1.5 m × 1.5 m to allow for easy management when the crop starts branching profusely.

Management

As a climber, worowo requires staking or planting under a horizontal trellis of about 1 m high. In plantations where worowo grows as a weed, cacao trees often serve as live stakes. Farmers purposely retain stands of worowo during cleaning operations. In home gardens the use of wooden poles is recommended. Side shade from hedges or trees is beneficial. In south-western Nigeria mulching is advantageous especially during the dry season. Since worowo quickly forms a dense canopy, weed growth is suppressed and manual weeding is required only once before the canopy closes. During the dry season worowo should be well watered. Farmers often cut back flowering shoots to favour leaf production. The quality of worowo leaves grown in gardens is comparable to those collected from cacao plantations or from the wild.

Diseases and pests

No serious diseases in worowo have been reported. In Nigeria some damage is caused by variegated locusts (Zonocerus variegatus) during the latter part of the dry season. Severe damage by green aphids (Aphis fabae) may occur from January–April, causing young shoots to curl and in extreme cases death of whole plants. Mealy bugs suck the leaves. They are particularly noxious on topped twigs with emerging new shoots.

Harvesting

Worowo is harvested throughout the year except during flowering. When properly managed, a stand of worowo can be harvested several times for two years, unless whole plants are harvested by uprooting. Harvesting is done by manually cutting the succulent parts of twigs. The first harvest may take place about 2 months after planting.

Yield

The leaf yield of worowo in cultivation is about 7 kg/m² at the first harvest and 40 kg/m² per year. Yields may be larger in the subsequent year if rainfall or irrigation is stable and flowering prevented.

Handling after harvest

Harvested leaves and tender shoots are tied into bunches for marketing and are sold fresh. They remain fresh for 3 days if kept in humid conditions. In south-western Nigeria farmers sometimes spread the harvested leaves in open baskets at about 8.00 p.m., exposing them to the cool night temperatures to keep the produce fresh before bringing it to the market.

Genetic resources

There is an urgent need to collect and preserve the genetic diversity of worowo. In Nigeria wild stands have been decimated and the species is becoming endangered due to massive exploitation without replacement.

Prospects

There is ample scope for improving the cultivation of this crop in Africa. It has long been neglected by research and no breeding or selection programmes of worowo are known. Once good husbandry methods and improved cultivars have been developed, more farmers will be able to incorporate the cultivation of this crop into their cropping systems.

Major references

• Adams, C.D., 1963. Compositae. In: Hepper, F.N. (Editor). Flora of West Tropical Africa. Volume 2. 2nd Edition. Crown Agents for Oversea Governments and Administrations, London, United Kingdom. pp. 225–297.

• Adebooye, O.C., 1996. Proximate composition and nutrient analyses of six selected leaf vegetables of Southwest Nigeria. Ife Journal of Agriculture 18(1–2): 56–62.

• Adebooye, O.C., 2000. An assessment of cultural practices for cultivating a wild but edible leaf vegetable: Crassocephalum biafrae (Asteraceae): Emphasis on propagation techniques. In: Proceedings of the third international workshop on the sustainable use of medicinal and food plants. September 15–17, 2000, University of Karachi, Karachi, Pakistan. pp. 132–138.

• Adebooye, O.C., 2001. Wild plants for medicinal and culinary use: Nigeria. In: Sharing innovative experience on sustainable use of indigenous food and medicinal plants. Third World Academy of Science and UNDP, Trieste, Italy. pp. 69–78.

• Burkill, H.M., 1985. The useful plants of West Tropical Africa. 2nd Edition. Volume 1, Families A–D. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 960 pp.

• Schippers, R.R., 2000. African indigenous vegetables. An overview of the cultivated species. Natural Resources Institute/ACP-EU Technical Centre for Agricultural and Rural Cooperation, Chatham, United Kingdom. 214 pp.

• Stevels, J.M.C., 1990. Légumes traditionnels du Cameroun: une étude agrobotanique. Wageningen Agricultural University Papers 90–1. Wageningen Agricultural University, Wageningen, Netherlands. 262 pp.

• van Epenhuijsen, C.W., 1974. Growing native vegetables in Nigeria. FAO, Rome, Italy. 113 pp.

• Zollo, P.H.A., Kuiaté, J.R., Menut, C. & Bessière, J.M., 2000. Aromatic plants of tropical Central Africa 36: Chemical composition of essential oils from seven Cameroonian Crassocephalum species. Journal of Essential Oil Research 12(5): 533–536.

Other references

• Jeffrey, C., 1986. The Senecioneae in east tropical Africa. Notes on Compositae 4. Kew Bulletin 41(4): 873–943.

• Olorode, O., 1974. Chromosome numbers in Nigerian Compositae. Botanical Journal of the Linnean Society 68(4): 329–335.

• Raponda-Walker, A. & Sillans, R., 1961. Les plantes utiles du Gabon. Paul Lechevalier, Paris, France. 614 pp.

Sources of illustration

• Stevels, J.M.C., 1990. Légumes traditionnels du Cameroun: une étude agrobotanique. Wageningen Agricultural University Papers 90–1. Wageningen Agricultural University, Wageningen, Netherlands. 262 pp.

• van Epenhuijsen, C.W., 1974. Growing native vegetables in Nigeria. FAO, Rome, Italy. 113 pp.

Author(s)

• O.C. Adebooye

Department of Plant Sciences, Faculty of Agriculture, Obafemi Awolowo University, Ife-Ife, Nigeria

Correct citation of this article

Adebooye, O.C., 2004. Solanecio biafrae (Oliv. & Hiern) C.Jeffrey. [Internet] Record from PROTA4U. Grubben, G.J.H. & Denton, O.A. (Editors). PROTA (Plant Resources of Tropical Africa / Ressources végétales de l’Afrique tropicale), Wageningen, Netherlands. <http://www.prota4u.org/search.asp>.

Accessed 18 December 2024.

• See the Prota4U database.