WINGED BEAN, Aparagus bean, or pea, Four-angled, or Four-cornered bean, Goa bean3, Manila bean, Mauntius bean5.
Psophocarpus tetragonolobus (L.) DC.
Amali, Batong-baimbing (Philipp.); Burma haricot; Calamismis (Philipp.); Chara konisem (Beng.); Chaudhaari-phali (Hind.); Chavdhari-ghevda (Bom.); Chichipir, Chipir (Indon.); Cigarillas (Philipp.); Dara d(h)ambala (Sri La.); Du cau (Viet.); Dragon bean, Fava de cavallo (Port.); Flgelbohne (Ger.); Garbanso (Philipp.); Haricot dragon (Fr.); Kachang blimbing, Kachang botol, Kachang botor (Mal.); Kachang embing (Indon.); Kachang kelisah, Kachang kotor (Mal.); Kalamismis (Philipp.); Katchang botor (Mal.); Katjeper, Kechipir, Ktjeepir (blinger), Ktjeper (Indon.); Lakar-sem (Beng.); Morisuavarai, Murukavari (Tam.); Pallang, Parupa-gulung (Philipp.); P-myt, Psaung-sa (-ye or -za) (Burma); Pois ail, Pois carr (Fr.); Princess pea, Sabidokong (Philipp.); See-kok-tau (China); Segidilla, Seguidilla, Sequidilla, Sererella (Philipp.); Sesquidilla (Sp.); Shambe kayi (Ind.); Sigarilya (Philipp.); Tjeepir bee-bas, Tjeepir we-loo, Tjeetjeepir (Indon.); Too-a poo, Tua pu (Thai.); Winged pea.
The winged bean is attracting attention as a potentially valuable multipurpose crop, pods, seeds, tubers and vegetative parts all being used, and it has been documented as such in a companion volume (TPI Crop and Product Digest No. 3-Food Legumes). The present account considers its uses as a tuber crop in greater detail, but in view of the value of its pods and seeds it seems unlikely that it will often be grown as a tuber crop alone; rather the tubers will continue to be a bonus from a primarily legume crop.
A climbing perennial, producing new growth annually from shallow, persistent roots, but for optimum results the winged bean is treated as an annual. The fibrous roots are numerous with the main laterals running horizontally near the soil surface; after a few months they usually become thickened and tuberous, near the base of the plant, though this does not occur in all strains. The roots are normally heavily nodulated. Plants in Malaysia may carry up to 440 large nodules each and their fresh weight can reach 800 kg/ha. A single nodule may weigh 0.6 g and have a diameter of up to 1.2 cm. The stem is moderately thick, slightly ridged and grooved, and can reach 3-3.6 m in height, if given support. The leaves are trifoliate, on long, stiff petioles; the leaflets are ovate, 7.5-15 cm long with the terminal one usually longer than the laterals and attached to the petiole by a marked pulvinus. The inflorescence is borne on an axillary raceme, up to 15 cm in length, with 2-10 flowers, which may be blue, white or lilac. It has been reported that pollination in some species is by bees, and in their absence pod-set is very low. The pods are four-sided, with characteristic serrated wings running down the four corners. They contain 5-20 seeds which can vary in colour from white, through varying shades of yellow and brown to black, and may also be mottled.
There are many different local strains of the winged bean. The species is not found growing wild although it has been noted growing as an escape in Burma and the Philippines. There are four closely-related species found wild in Africa, of which P. palustris Desv. and P. scandens (Endl.) Verdc. (syn. P. Iongipedunculatus Hassk.) are occasionally cultivated.
Origin and distribution
The winged bean is thought to have originated in Africa (Madagascar or Mauritius) and to have spread to Asia, and is now cultivated usually as a market garden crop in southern India, Burma, Malaysia, New Guinea, Indonesia, the Philippines, China and Thailand, and to a lesser extent in Africa, mainly in Ghana and Nigeria, and in the West Indies.
Temperature-it is a tropical crop resistant to high temperatures, grown between 20°N and 15°S latitude.
Rainfall-well-distributed rainfall in excess of 150 cm per year is required and the plant thrives in areas with an annual rainfall of 250 cm or more. It can be grown as a dry season crop, provided that there is adequate irrigation and the water does not remain on the soil, as this tends to reduce the growth of roots and root tubers. Despite its perennial nature and extensive root-system, it does not survive prolonged drought, though drought-resistant cultivars are being developed.
Soil-the winged bean is not very demanding in its soil requirements, provided that there is adequate drainage. It cannot tolerate waterlogging or salinity. Well-cultivated, rich, sandy loams are best for optimum yields of pods; on clay soils the tubers are frequently small and lacking in flavour. It is frequently grown successfully in nitrogen-poor soils because of its exceptional ability to nodulate. However, recently in Nigeria, experimentally-grown winged beans have made comparatively slow growth accompanied by markedly chlorotic, light-green foliage, which suggests that the rate of nodulation is very dependent upon the availability of the most effective rhizobial strains, probably of the cowpea group. The manurial requirements of the winged bean have not been studied in detail, but it responds favourably to nitrogen fertilisation. When grown as a vegetable the routine application of standard NPK fertiliser at intervals of 14-21 days has been recommended.
Altitude-it can be grown at elevations up to about 2 000 m in the tropics.
Day-length-the winged bean requires short days for normal flower induction, since when grown under a long photoperiod there is excessive vegetative growth at the expense of flowers. Recent experiments have shown that there is an interaction between day-length and day/night temperatures; both flowering and tuberisation are inhibited in 16 hour days, but with 8 hour days tubers formed regardless of temperature, but flowering was dependent upon the temperature regime used.
Material-seed, which is viable for approximately one year, is normally used. Problems handicapping the future development of this crop are the lack of adequate commercial supplies of seeds and the genetic variability of existing supplies. In certain areas of Burma and the Philippines the crop is treated as a perennial and the tubers are left in the ground to produce fresh plants. A great deal of work is currently underway breeding new cultivars to suit specific conditions and for tuber production.
Method-the winged bean is often interplanted with sweet potatoes, taro, bananas, sugar cane or other vegetable crops. For pod and seed production planting is usually on the flat and the seeds are dibbed in holes about 2.5 cm deep, at the beginning of the rainy season. It is usual to provide the winged bean with supports; bamboo poles arranged singly, or in tripods, are often used. When poles are used the plants may grow so tall that picking is difficult and the use of a trellis or wire fence 1-1.5 m high has been recommended. In Burma, where the crop is grown on a field scale for the production of tubers, the seeds are normally planted 5-7.5 cm deep on ridges and earthed up, stakes are frequently dispensed with, and the plants are left to ramble over the ground reaching a height of 30 cm. The effect of staking on the yield of root tubers has produced conflicting evidence, but the cost of staking may well offset any increase in yield. Seedlings make slow growth for the first 3-5 weeks and efficient weed control is usually necessary until they are well established.
Field spacing and pruning-in Burma, for tuber production on a field scale, planting is on ridges about 20 cm high and 60 cm crest to crest, at 7.5-15 cm along the ridge (200 000-100 000/ha); recent work suggests that about 150 000/ha is the optimum figure. Often two or three seeds are used at each planting point; this requires approximately 500 kg seed/ha.
Although new varieties will produce fruit and root tubers, reproductive pruning (ie removal of flowers) increases root tuber production dramatically (an average of four-fold in reported experiments).
Pests and diseases
When grown in mixed market garden culture or shifting agriculture the winged bean is generally free from serious pests and diseases, though occasionally attacked by caterpillars, leaf miners, grasshoppers, spider mites and nematodes. Probably the most serious disease, which occurs in Papua
New Guinea, Java, the Philippines and Malaysia, is false rust, caused by Synchytrium psophocarpi, which may be controlled by copper fungicides. In plantations Cercospora spp. cause leaf spot, though not to the extent of producing defoliation. Caterpillars of Podalia spp. have been reported from Brazil as serious, and also the mites Polyphagotarsonemus latus and Tetranychus virticae. Viral symptoms have been observed in Nigeria and the Ivory Coast. It is probable that, as plantation-type plantings increase, disease problems will become more severe and many disease-causing organisms have been listed in recent literature. In particular, root knot nematodes have been reported to cause up to 70 per cent losses in tuberous roots: Meloidogyne incognita has been recorded as more aggressive than M. javanica.
Production of pods starts within 2 months and continues for several weeks. However, when grown for tubers, harvesting is normally 4-8 months after sowing.
Harvesting and handling
The root tubers are normally harvested when they reach 2.5-5 cm in diameter and 7.5-12 cm in length. Lifting is usually by fork, care being taken to avoid damage; the practice of growing the plants on ridges facilitates this operation. Where grown on the flat, the ground is sometimes flooded to make digging easier and to reduce the possibility of injury. There is little information on storage of the root tubers as they are normally eaten immediately after harvest, but it has been found that under normal tropical conditions deterioration is rapid (loss of moisture, loss of vitamin C and long cooking time), but at lower temperatures and higher humidities storage for a few weeks was possible, provided that fungal growth was prevented.
In the present context, the tuberous portions of the roots are considered to be the primary product. These are roughly cylindrical, with a brown, fibrous skin, up to 12 cm in length and weighing about 50 g. The flesh is white and solid, and after peeling they are eaten raw or boiled. They are described as having the texture of an apple and tasting slightly sweet. They are most suitable for eating when quite small (about 2.5 cm thick), as they become increasingly fibrous and of poorer flavour when more mature.
Yields of root tubers are greatly influenced by conditions of growth, altitude, variety, etc, and virtually all reported yields are from crops grown primarily for pod or seed. Malaysia has reported 2.5-6 t/ha and the Philippines 2.3 t/ha. In Indonesia, higher altitudes were stated to favour root tuber production rather than that of pods, and in cool highlands yields were 6-16 t/ha, in lowland areas much less. In Papua New Guinea also, higher yields were reported from the highlands, and in recent experiments in Malaysia 14 t/ha from staked plants of selected strains in experimental plantings. In none of these cases was reproductive pruning practiced.
Pods, seeds, foliage and flowers are all used in human nutrition (see TPI Crop and Product Digest, No. 3-Food Legumes). There is also some use of the vegetative parts or of the whole plant as animal feed.
Root tubers-the protein content is exceptionally high for root crops, normally 12-15 per cent of the fresh weight. The water content of the fresh tubers is 52-68 per cent. The composition of the dry matter has been given as: protein 13-20 per cent; fat 0.6-1.4 per cent; carbohydrate 63-77 per cent; fibre 1.5-21 per cent; ash 1.7-3.9 per cent; calcium 40 mg/100 g; iron 3 mg/100 g; phosphorus 64 mg/100 g.
The wide range of values appears to be associated with variety and possibly with maturity of the root tubers.
The carbohydrate is about 80 per cent starch and 20 per cent sugars. In this analysis the non-protein nitrogen was 7.4-15 per cent of the crude protein but other reports have found values as high as 50 per cent. Sulphur-containing amino acids are low but the aspartic acid content is exceptionally high.
The root tubers have high levels of trypsin inhibitory activity (13 500 - 30 100 IU/mg fresh weight); this is inactivated by cooking.
Forage and animal feed-analyses of the whole plant in connection with its possible use as animal feed are:
Seeds-protein 42 per cent; neutral detergent soluble fraction 77 per cent; in vitro digestibility 92 per cent.
Young leaves-protein 34 per cent; neutral detergent soluble fraction 69 per cent.
Old leaves-protein 24 per cent.
Green pods-protein 22 per cent.
Dry pods without seeds-protein 9 per cent; lignin 15 per cent; in vitro digestibility 62 per cent.
Old stems-protein 11 per cent; lignin 17 per cent; in vitro digestibility 58 per cent.
Young stems-lignin 13 per cent; in vitro digestibility 64 per cent.
Root tubers-protein 20 per cent; neutral detergent soluble fraction 72 per cent; in vitro digestibility 95 per cent.
The neutral detergent soluble fraction is the carbohydrate and protein available to ruminants. Lignin was the most important factor in depressing in vitro digestibility.
The use of sun-dried chips of the root tubers, dried haulms, leaves and seed cakes, mixed with tapioca chips and pelletised, has been proposed for animal feed.
Production and trade
No statistical data are available.
Winged bean is of rapidly increasing interest as a high-protein multipurpose crop, particularly for cultivation in the humid tropics, where the incidence of protein deficiency in human diets is often very difficult to remedy. All parts of the plant are edible, ie seeds, root tubers, leaves and flowers. The seeds, which are very similar nutritionally to soyabeans, have the advantage that they have a pleasant sweet flavour in contrast to the rather bitter flavour of the soyabean. Like the soyabean, the winged bean could be utilised as a source of edible oil and has potential as a substitute if commercial production could be developed. Another interesting feature of the crop is the high protein content of the root tubers which could help alleviate protein deficiency in local diets. In addition, the exceptional ability of the crop to fix atmospheric nitrogen by bacteria in the root nodules should not be overlooked, in view of the world shortage and rising prices of artificial nitrogenous fertilisers.
It has been suggested that in the future the winged bean could become as important as the soyabean in world agriculture, with the added bonus of yielding substantial quantities of edible, high-protein root tubers. Considerable research is currently underway. While the plant in its present form is suitable for garden or smallholding use, requiring staking or rambling tangled over the ground, large-scale cultivation would be much more practicable with a low-growing determinate cultivar; also, a plant with a clearly-defined flowering season would enable deflowering to be carried out as a single field operation if the crop were being grown specifically for tubers.
The TPI Crop and Product Digest, No. 3-Food Legumes contains a comprehensive bibliography of publications up to 1976. Poulter, N. H. and Dench, J. E. 1981. The Winged Bean (Psophocarpus tetragonolobus (L.) DC). An Annotated Bibliography, London: Tropical Products Institute, 233 pp., contains 397 references of which 331 are subsequent to 1976. In the following bibliography all entries identified by an abstract (Abs.) number are quoted from Poulter and Dench.
BALA, A. A. and STEPHENSON, R. A. 1078. The genetics and physiology of tuber production in winged bean. The Winged Bean: Papers presented at the 1st International Symposium on developing the potentials of the Winged Bean (Philippines, 1978), pp. 63-70. Los Baos, Laguna, Philippines: Philippine Council for Agriculture and Resources Research, 448 pp. (Abs. 62).
BEAUMONT, J. H. et al. (16 authors). 1981. Food uses of the winged bean, Psophocarpus tetragonolobus (L.) DC. 2nd International Symposium on Winged Bean (Sri Lanka). Colombo, Sri Lanka. (Abs. 189).
CERNY, K. 1978. Comparative nutritional and clinical aspects of the winged bean. The Winged Bean: Papers presented at the 1st International Symposium on developing the potentials of the Winged Bean (Philippines, 1978), pp. 281-299. Los Baos, Laguna, Philippines: Philippine Council for Agriculture and Resources Research, 448 pp. (Abs. 101).
CLAYDON, A. 1977. An investigation into the storage of winged bean tubers. Agriculture in the Tropics: Papers delivered at the 10th Waigani Seminar (Papua New Guinea, 1976) (Enyi, B.A.C. and Varghese, T., eds), pp. 499-516. Lae, Papua New Guinea: University of Papua New Guinea, 523 pp. (Abs. 192).
CLAYDON, A. 1978/1979. How important a food is winged bean in Papua New Guinea? Science in New Guinea, 6, 144-153. (Abs. 106).
DRINKALL, M. J. 1978. False rust disease of the winged bean. PANS, 24, 160 - 166. (Abs. 324).
DUNCAN, L. W., CAVENESS, F. E. and PEREZ, A. T. 1979. The susceptibility of winged bean (Psophocarpus tetragonolobus) to the root-knot nematodes, Meloidogyne incognita, race 2, and M. javanica. Tropical Grain Legume Bulletin, 15, 30 - 34. (Abs. 326).
EAGLETON, G. E., THURLING, N. and KHAN, T. N. 1981. Genotypic variation in the response of winged bean (Psophocarpus tetragonolobus (L.) DC) to difference in environment. 2nd International Symposium on Winged Bean (Sri Lanka). Colombo, Sri Lanka. (Abs. 269).
EVANS, I. M., BOULTER, D., EAGLESHAM, A. R. J. and DART, P. J. 1977. Protein content and protein quality of tuberous roots of some legumes determined by chemical methods. Qualitas Plantarum: Plant Foods for Human Nutrition, 27, 275-285. (Abs. 174).
FLECHMANN, C. H. W. 1981. Observations on winged beans (Psophocarpus tetragonolobus (L.) DC) in Sao Paulo, Brazil. 2nd International Symposium on Winged Bean (Sri Lanka). Colombo, Sri Lanka. (Abs. 328).
HERATH, H. M. W. and FERNANDEZ, G. C. J. 1978. Effect of cultural practices on the yield of seed and tubers in winged beans. The Winged Bean: Papers presented at the 1st International Symposium on developing the potentials of the Winged Bean (Philippines, 1978), pp. 161-172. Los Baos, Laguna, Philippines: Philippine Council for Agriculture and Resources Research, 448 pp. (Abs. 222).
HILDEBRANT, D. F., CHAVEN, C., HYMIOWITZ, T. and BRYAN, H. H. 1981. Variation in storage root protein content in winged beans, Psophocarpus tetragonolobus (L.) DC. 2nd International Symposium on Winged Bean (Sri Lanka). Colombo, Sri Lanka. (Abs. 117).
JALANI, B. S. and WONG, K. C. 1981. Research activities and status of winged bean (Psophocarpus tetragonolobus) in Malaysia. 2nd International Symposium on the Winged Bean (Sri Lanka). Colombo, Sri Lanka. (Abs. 223).
KARIKARI, S. K. and OTENG, S. 1977. The effect of staking on the growth and yield of the winged bean (Psophocarpus tetragonolobus (L.) DC). Acta Horticulturae, 53, 159-163. (Abs. 229).
KAY, D. E. 1979. TPI Crop and Product Digest, No. 3-Food Legumes. London: Tropical Products Institute, xvi+435 pp.
KESAVAN, V. 1981. Green pod and tuber yield in winged bean in low and high lands of Papua New Guinea. 2nd International Symposium on Winged Bean (Sri Lanka). Colombo, Sri Lanka. (Abs. 279).
LAMB, K. P. and PRICE, T. V. 1978. Insect and mite pests of winged bean and their control. The Winged Bean: Papers presented at the 1st International Symposium on developing the potentials of the Winged Bean (Philippines, 1978), pp. 231-235. Los Baos, Laguna, Philippines: Philippine Council for Agriculture and Resources Research, 448 pp. (Abs. 335).
LON, J. 1977. Origin, evolution and early dispersal of root and tuber crops. Proceedings of the 4th Symposium of the International Society for Tropical Root Crops (Colombia, 1976), IDRC-080e (Cock, J., MacIntyre, R. and Graham, M., eds), pp. 20-36. Ottawa, Canada: International Development Research Centre, 277 pp.
OKEZIE, O. B. and MARTIN, F. W. 1980. Chemical composition of dry seeds and fresh leaves of winged bean varieties grown in the US and Puerto Rico. Journal of Food Science, 45, 1045- 1051. (Abs. 126).
ONOSIROSAN, P. T. 1981. Diseases of winged bean (Psophocarpus tetragonolobus) in Southern Nigeria. 2nd International Symposium on Winged Bean (Sri Lanka). Colombo, Sri Lanka. (Abs. 339).
PHILIPPINE COUNCIL FOR AGRICULTURE AND RESOURCES RESEARCH. 1978. The Winged Bean: Papers presented at the 1st International Symposium on developing the potentials of the Winged Bean (Philippines, 1978). Los Baos, Laguna, Philippines: Philippine Council for Agriculture and Resources Research, 448 pp. (Abs. 36).
PITAKARNNOP, N. 1981. Production of pellets from winged bean tubers and seed cake for animal feed. 2nd International Symposium on Winged Bean (Sri Lanka). Colombo, Sri Lanka. (Abs. 201).
POULTER, N. H. 1982. Some characteristics of the roots of the winged bean (Psophocarpus tetragonolobus (L.) DC). Journal of the Science of Food and Agriculture, 33, 107- 114.
PRICE, T. V. and MUNRO, P. E. 1978. Fungi associated with collar rot of winged bean in Papua New Guinea. PANS, 24, 53-56. (Abs. 342).
RAO, P. U. and BELAVADY, B. 1979. Chemical composition and biological evaluation of Goa beans (Psophocarpus tetragonolobus) and their tubers. Journal of Plant Foods, 3, 169- 174. (Abs. 130).
SINNAOURAI, S. 1977. Studies on winged bean in the Coastal Savannah (Accra Plains) of Ghana. Tropical Grain Legume Bulletin, 10, 14-15. (Abs. 254).
STEPHENSON, R. A. 1978. Field studies on winged bean growth and yield. The Winged Bean: Papers presented at the 1st International Symposium on developing the potentials of the Winged Bean (Philippines, 1978), pp. 191-196. Los Baos, Laguna, Philippines: Philippine Council for Agriculture and Resources Research, 448 pp. (Abs. 256).
WATSON, J. D. 1977. Chemical composition of some less commonly used legumes in Ghana. Food Chemistry, 2, 267-271. (Abs. 136).
WATSON, J. D., DAKO, D. Y. and AMOAKWA-ADU, M. 1975. Available carbohydrates in Ghanaian foodstuffs. Plant Foods for Man, 1, 169- 176. (Abs. 188).
WONG KAI CHOO. 1978. Agronomy of the winged bean in Malaysia. The Winged Bean: Papers presented at the 1st International Symposium on developing the potentials of the Winged Bean (Philippines, 1978), pp. 220-226. Los Baos, Laguna, Philippines: Philippine Council for Agriculture and Resources Research, 448 pp. (Abs. 297).
WONG KAI CHOO. 1981. Environmental factors affecting the growth, flowering and tuberization in winged bean (Psophocarpus tetragonolobus (L.) DC). 2nd International Symposium on Winged Bean (Sri Lanka). Colombo, Sri Lanka. (Abs. 78).
YAP, T. N., SOEST, P. J. van and MCDOWELL, R. E. 1979. Composition and in vitro digestibility of the winged bean (Psophocarpus tetragonolobus) and possible utilization of the whole plant in ruminant feed. Malaysian Applied Biology, 8, 119-123. (Abs. 140).