Phaseolus vulgaris (PROSEA)
- Protologue: Sp. Pl. 1: 723 (1753).
- Family: Leguminosae
- Chromosome number: 2n= 22
- Phaseolus esculentus Salisb. (1796).
- Common bean (En)
- haricot commun (Fr)
- Philippines: butingi, mula
- Indonesia: buncis
- Malaysia: kacang buncis, kacang merah
- Thailand: thua khaek, thua phum
- Vietnam: dâu ve
- Laos: thwàx fàlangx
- Cambodia: sândaèk barang
- Burma: bo-sa-pè, pè- bya-galè, pè-gya(ni).
Origin and geographic distribution
Common bean originated in the Americas and domesticated in Mexico, Peru and Colombia ca. 8000 years ago. Prior to Columbus it was unknown in the Old World, but later it has become an important crop in Europe and Africa. It is widely cultivated in many parts of the tropics and subtropics and throughout the temperate regions. Common bean is the most important pulse crop throughout tropical America and many parts of tropical Africa. It is of little importance in India and most of tropical Asia, where indigenous pulses are preferred.
Common bean is used as a pulse and as a green vegetable. The young pods and ripe seeds are eaten and, to a lesser extent, also the green-shelled seeds. In some parts of the tropics young leaves are used as a spinach. In temperate regions common bean is grown mainly for the green immature pods which are eaten as a vegetable and are also canned and frozen. The dried seeds are also cooked with tomato sauce and canned. The straw is used as fodder. Preparation is by boiling; eaten with a wide range of meat and vegetable sauces beans are very acceptable. The straw can be used as forage.
As a pulse common bean can be utilized interchangeably with cowpea. Their use, however, is complementary since temperature optima for the cowpea are higher than for the common bean.
Production and international trade
Production data for 'dry beans' in FAO statistics must be treated with caution. This category includes produce from species of Vigna and other genera. Production of common bean alone accounts for approximately 95% of the total world Phaseolus bean production of 8,3 million t. Less than 5% of total production is from the other three cultivated species (estimates from world dry bean production in 1979 discounting known non-Phaseolus species). Common beans are grown extensively in five major continental areas: eastern Africa, North, Central and South America, eastern Asia, and western and south-eastern Europe. Roughly 30% of world production is in tropical America. Brazil is by far the largest bean producing nation in the world with 2,3 million t (including some cowpeas) over the period 1973-1975.
Average contents per 100 g edible portion are: for dry seed: water 10 g, protein 22.6 g, fat 1.4 g, carbohydrates 62 g, fibre 4.3 g and ash 3.7 g. The energetic value averages 1453 kJ. For green pods: water 91 g, protein 1.8 g, fat 0.2 g, carbohydrates 6.6 g, fibre 1 g and ash 0.7 g. The energetic value averages 126 kJ/100 g. For fresh leaves: protein 3.6 g, a high vitamin C content (110 μg) and also high contents of vitamin A precursors. The energetic value averages 151 kJ/100 g. The contents vary in composition according to genotype and production locality. Dry beans must be thoroughly cooked before being eaten since raw beans contain an array of antimetabolites. Bean seeds contain significant amounts of thiamine, niacin, folic acid as well as fibre. In general, deeply coloured, red and black beans, are relatively rich in tannins as compared to pale and lightly variegated types, and tannins are considered to reduce the dietary value of the protein. Weight of 100 seeds is 20-200 g.
- A climbing, vining or bushy, slightly pubescent annual with well-developed taproot, laterals and adventitious roots. Sometimes globular nodules are present. Stem angular or nearly cylindrical.
- Leaves alternate, trifoliolate; petiole usually up to 15 cm long, grooved above, with basal pulvinus; basal leaflets asymmetrical, apical leaflet symmetrical, usually ovate, 7.5-14 cm × 5.5 x 10 cm.
- Inflorescence axillary or terminal racemes with several to many white, pink, lilac or purple flowers; calyx campanulate; corolla papilionaceous; stamens diadelphous (9 + 1); ovary laterally compressed with 4-12 (commonly 7) ovules; style upturned and spiralled with collar of fine hairs below the stigma; stigma ellipsoid, glandular, directed adaxially.
- Pod linear, up to 20 cm long, straight or more commonly somewhat curved with a prominent beak, fleshy when immature, green or yellow, sometimes purple or reddish to purplish spotted or striped.
- Seeds highly variable in size, shape and colour; ovoid, subspherical or kidney-shaped; black, brown, yellow, red and white with speckled, flecked, saddled and darker patterns superimposed.
- Seedling with epigeal germination; first two leaves simple and opposite, subsequent leaves alternate, trifoliolate.
Growth and development
Seedlings usually emerge within a week after sowing at a soil temperature of 16 °C, at lower temperatures it may take up to 2 weeks. Two growth-types of common beans are distinguished: determinate, in which the main axis terminates in an inflorescence and produces no vegetative nodes after flowering, and indeterminate. Determinate plants of common bean have a central axis (the main stem) with 5-9 nodes, and from two to several branches which arise from the more basal nodes. Indeterminate plants have a central axis with 12-15 nodes, or even more in climbing vine-types. Time to flowering varies with cultivar, temperature and photoperiod and is usually from 28-42 days. Flowering is usually completed in 5-6 days at 20-25 °C in determinate bush genotypes, and in 15-30 days in indeterminate climbing genotypes. Climbing cultivars can flower over a much longer period if immature pods are harvested. Flowers open at sunrise and fade at sunset. Usually self-pollination occurs, frequency of cross-pollination is low. As many as two-thirds of the flowers produced may abort, and under temperature or moisture stress young fruits and developing seeds may abscise as well. Abscission is greatest in flowers formed on the later nodes and branches, and in the later flowers or racemes with multiple flowers. Seed-filling period may extend from as few as 23 days to nearly 50 days. Full maturity, that is, to dry seed, is reached 65-150 days after sowing.
Other botanical information
CIAT has classified the world common bean collection into four main growth habit types on the basis of determinacy, node production after flowering and growth habit (height and climbing tendency):
- I dwarf determinate habit, with reproductive terminals on main stem and no further node production on main stem after flowering (short, self-supporting or bushy type of short growth duration);
- II dwarf indeterminate habit, vegetative terminal on main stem and further node production on main stem after flowering, with erect branches borne on lower nodes;
- III prostrate indeterminate habit, moderate to considerable node production on main stem after flowering, with variable number of branches borne on lower nodes, and with prostrate to cone-shaped canopy on supports;
- IV climbing indeterminate habit, heavy node production on main stem after flowering, with branches not well developed compared to main stem development, with moderate to strong climbing-ability on supports.
Pod texture is closely related to use. Leathery pods, with reduced parchment tissue are used both for dry seed and green bean production as they remain tender until the rapid phase of seed growth occurs. Stringless pods remain tender when seeds are quite large, and are extensively traded frozen.
Generally beans are classified according to their use as follows:
- snap or string beans, grown for the pods harvested before fully grown and while still slender, with small seeds (e.g. green-podded bush cultivars, wax or yellow-podded bush cultivars, green-podded climbing cultivars, wax or yellow-podded climbing cultivars);
- green-shell beans, used in the green-shelled condition (bush cultivars, climbing cultivars);
- dry-shell or field beans, grown for the dry, ripe seeds (medium field beans with seeds 1-1.2 cm long, pea or navy beans with seeds up to 8 mm long, red kidney beans with seeds 1.5 cm long or more, and marrow beans with seeds 1-1.5 cm long).
Common bean is a quantitative short-day plant. For every genotype there is an optimum photoperiod-temperature regime in which that genotype will flower after the smallest possible number of days from emergence. Deviations in either temperature or photoperiod cause delays in flowering. Most common beans are grown within a relatively narrow range of temperatures: (17.5-)20-22.5(-25) °C, and in the equatorial tropics they are only found at higher elevations (above ca. 1000 m). Growth conditions below or above the optimum temperature range cause yield reductions that are related to plant mortality (at high temperatures), reduced photosynthesis, and failure of flowers to produce mature pods (50-70% of opened flowers). Common beans are sensitive to nightfrost. A moderate, well-distributed rainfall is required (300-400 mm per crop cycle), but dry weather during harvest is essential. Drought or waterlogging are detrimental. Suitable soil types range from light to moderately heavy and peaty soils with near neutral pH and good drainage. Common bean is quite susceptible to salinity.
Normal propagation is by seed, but for special purposes stem cuttings can be rooted easily. Plant populations consist of 150 000-200 000 plants/ha for dwarf cultivars and half this for climbing types in sole cropping. In intercropping densities are much lower. Plant densities vary for bush cultivars in sole cropping from 30-45 cm between the rows and 30 cm in the rows. Wider spacing to 75-90 cm × 10-15 cm makes weeding easier. For climbing beans usually 4-6 seeds are sown together in hills spaced about 1 m apart; they may also be sown in rows at a spacing of 90-120 cm × 15-30 cm. Depth of sowing varies from 3-6 cm. Seed rate depends on seed size and intended plant population densities, up to 120 kg/ha for dwarf beans and 60 kg/ha for climbers in sole cropping.
In North America, Europe and in limited areas of other producing regions common beans are extremely commercialized. Bush types predominate here since they are well suited to intensive cultivation. Most sole-cropped beans are grown as a high-input crop with yield potentials ranging between 1000 and 3000 kg/ha. In subsistence cultivation landraces of different plant types and seed colours are grown in complex intercropping systems. It is estimated that 75-80% of the common beans in tropical America are cultivated in some form of intercropping, mostly with maize.
Flat cultivation is preferred to ridges. Disturbance of the soil should be avoided because damaging the roots or the collar of the plant involves risks of diseases. So, shallow cultivation is preferred especially in the period before flowering. Common bean can be grown rainfed or irrigated. Irrigation is beneficial in semi-arid regions, with overhead irrigation preferred to flood irrigation. In peasant cultivation the crop is seldom manured. Crop rotation is an important means to reduce disease incidence.
Diseases and pests
Common diseases in the tropics are web blight (Rhizoctonia microsclerotia), common blight (Xanthomonas phaseoli), root rots (Fusarium spp.,Rhizoctonia spp. and Macrophomina spp.), rust (Uromyces phaseoli), anthracnose (Colletotrichum lindemuthianum), angular leaf spot (Isariopsis griseola), the viruses common mosaic (BCMV) and the golden bean mosaic (GBMV).
Control of seed-borne diseases is achieved by sowing disease free seed, good rotational practice and disposal of infected plant debris. Genetic resistance to rust, anthracnose and angular leaf spot is useful but production of new virulent biotypes is a problem. Soil-borne diseases and nematode pests (Meloidogyne and Pratylenchus) are difficult to control otherwise than by rotation, although potentially useful genetic resistance is known.
Insect pests, while numerous, especially in tropical America, are often of localized significance. Many species of aphids and leaf hoppers are pests of common beans, as well as numerous Lepidopterous caterpillars and Chrysomelid beetles. Beans beetle (Acanthoscelides obtectus) and cowpea beetles (Callosobruchus spp.) are widespread in the tropics, attacking growing seeds and also the dried ones. The most serious pests of the dried pulse are bean weevils (Bruchus spp.). The beanfly (Melanagromyza phaseoli) is an important pest in Africa and Asia. Control of pests by chemicals such as carbaryl can be useful. Complete control of bruchids can be achieved by coating stored seeds with cotton seed oil. Pyrethrins are very effective in controlling weevils. Incorporation of genetic resistance to new cultivars could be important.
Snap beans are harvested before the pods are fully grown. Harvest starts 7-8 weeks after sowing in early cultivars. Pods should be picked every 3-4 days and the number of pickings is greater in climbing cultivars than in bushy ones. Dry beans are harvested as soon as a considerable percentage of the pods are fully mature and have turned yellow. Some cultivars have a tendency to shatter. Usually entire plants are pulled out. With large-scale cultivation the crop is harvested mechanically.
Seed yield may be in excess of 1.3 t/ha but may only be half of this or less under poor cultural conditions. Green pod yield of 5 t/ha is not exceptional.
Handling after harvest
Harvested plants are dried for a few days in the windrow, stacked and threshed when dry. Seed should be dry, clean and free from mechanical damage before being stored under optimal conditions. Dry beans of all types may be canned successfully, whereas immature pods of certain cultivars of snap bean are a very popular processed vegetable.
The primary gene pool is well represented in collections of CIAT, the USA and USSR and many smaller national collections. The wild component of this gene pool requires further exploration and collection between Mexico and Argentina. The secondary gene pool consists ofP. coccineusandP. polyanthus. The tertiary gene pool includes most other Phaseolus species.
Breeding objectives include resistance to the common pests and diseases, the production of lectin-free genotypes, improved nitrogen fixation capacity especially in dwarf, early maturing, cultivars, improved canopy architecture in relation to improved yielding capacity and resistance/tolerance to environmental stress.
Factors negatively affecting the prospects of common bean are the relatively long cooking period they require, the presence of anti-nutritional factors and a flatulence factor, and their susceptibility to the development of hard-shell and off-flavours during storage. Improvement of storage and processing methods and development of new food products could increase consumption considerably in many producing countries. Increased efficiency of production will require improved morphological, ecological, physiological and biochemical efficiency of the plant, available genetic resources are adequate for this purpose.
- Adams, M.W., Coyne, D.P., Davis, J.H.C., Graham, P.H. & Francis, C.A., 1985. Common bean (Phaseolus vulgaris L.). In: Summerfield, R.J. & Roberts, E.H. (Editors). Grain legume crops. Collins, London. p. 433-476.
- CIAT, 1976-1980. Abstracts on Field Beans (Phaseolus vulgaris L.). Vol. 1-5. Cali, Colombia.
- Duke, J.A., 1981. Handbook of Legumes of World Economic Importance. Plenum, New York. p. 195-200.
- Janssen, W., 1988. Snap beans: present status in the developing world and bibliography of research (1919-1987). CIAT, Cali, Colombia. 411 pp.
- Kay, D.E., 1979. Crop and Product Digest No. 3 - Food Legumes. Tropical Products Institute. London. p. 124-176.
- López, M., Fernández, F. & van Schoonhoven, A. (Editors), 1985. Frijol: Investigación y Producción. PNUD & CIAT. Cali, Columbia. 417 pp. (English edition in preparation).
- J. Smartt