Pisum sativum (PROSEA)
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Introduction |
- Protologue: Sp. Pl. ed. 2: 727 (1753).
- Family: Leguminosae
- Chromosome number: 2n= 14
Vernacular names
- Pea (En)
- Pois (Fr)
- Indonesia: kapri, kacang polong
- Malaysia: kacang ercis.
- Philippines: citzaro
- Burma: sadaw-pè
- Cambodia: sândaèk muul
- Vietnam: dâu hoà lan
Origin and geographic distribution
Probably originated in South-West Asia; now cultivated in a large number of temperate zone countries, as a cool season crop in the subtropics, and at higher altitudes in the tropics.
Uses
Dry seeds are used for human and animal consumption; for the former they are cooked whole, split or ground into flour and boiled or roasted. Large quantities are canned. Fresh peas are an important vegetable and in the immature form they are canned or frozen. Some cultivars are grown for their tender green pods. Plants are also suitable as forage, hay, silage and green manure.
Production and international trade
World production for dry and green peas in 1985 was 11.6 million t and 4.9 million t from areas of 8.9 million ha and 778 000 ha, respectively. The world price for dry peas in 1987 was US$ 480 per tonne. In the Far East 520 000 t were produced in 1986 from 675 000 ha.
Properties
Mature round seeded cultivars have per 100 g edible portion: water 10—13 g, protein 16—33 g, fat 1—2.5 g, carbohydrates 49—62 g (starch 43—56 g, sugars 6 g), fibre 4.5 g, ash 2—3 g. The energetic value averages 1428 kJ/100 g. Wrinkled forms have starch 27—37 g, sugars 10 g, similar amounts of protein, although with less sulphur amino acids than round forms, and fat 5 g. Peas are relatively free of anti-nutritional factors. Cultivars with a dark testa contain tannin which can lessen their digestibility. Weight of 100 seeds varies from 3 to 48 g.
Botany
- An annual, climbing herb, primitive forms up to 3.5 m tall, modern cultivars as short as 30 cm.
- Leaves pinnate with 2-3 pairs of leaflets and a terminal tendril, at base with 2 leaf like stipules; leaflets sometimes converted to tendrils.
- Flowers in axillary, 1-2 flowered racemes with a calyx of 5 green united sepals and a corolla of 5 white, purple or pink petals; anthers 10, diadelphous; ovary with 4 to 15 ovules.
- Fruit 3-11 cm long, sometimes with a tough inner membrane, with 3-11 seeds.
- Seeds round or wrinkled, varying in colour.
They germinate rapidly (hypogeal) and develop to maturity in 80-150 days. Flower initiation varies markedly with cultivar and daylength but in long days can be within three weeks of sowing at 18 °C. The period of flowering can be as little as 2-3 weeks in modern cultivars but is much longer in more primitive forms. The flowers are strictly self pollinated. Classification is mainly on seed type - whether round or wrinkled; the former are grown mainly for harvesting as mature seed and the latter for canning and freezing in the immature form.
Agronomy
Seed is sown at a depth of 4-7 cm at a rate of 23 g/m2 or 65-280 kg/ha, with highest rates for garden peas; seed bed compaction and weed competition should be avoided. Pea weevil (Sitona lineatus) is a common pest but is controlled by applying insecticides at the time of flowering. Root rots caused by a complex of fungal pathogens are avoided by adequate crop rotation which should be at least 3-5 years. In humid areas, downy mildew (Peronospora pisi) and in hotter areas, powdery mildew (Erysiphe pisi) are important fungal pathogens. Virus diseases can be a problem. Average yields in Asia and the world are around 1.2 t/ha (4 t/ha in France). For green peas the value for these three respective areas are are 4, 6 and 7.5 t/ha.
Genetic resources and breeding
Germplasm collections are found in 24 centres. The only wild relatives are primitive forms. Many useful genes for disease resistance are found in the centres of diversity in the Near and Middle East. The main breeding objectives are improving the standing capacity of the crop, disease resistance and higher yields. Selection for tolerance to stress factors such as drought, temperature extremes and waterlogging should improve the stability of yields.
Ecology
Peas grow reasonably well between 10 and 30° C with an optimum of around 20° C. A rainfall as low as 400 mm/year will suffice with an optimum of about 1000 mm/year. In tropical regions the crop has to be grown above circa 1200 m. Peas tolerate a wide range of soil types but thrive best on a well drained one which is slightly acid. Time of sowing and place in the rotation depend on regional climate. Dry peas are primarily grown as a break or catch crop in cereal rotations.
Prospects
Peas are in large demand for culinary purposes also in the tropics. Improved yields through better standing capacity and disease resistance should be readily obtained.
Literature
- Ayad, G. & Anishetty, N.M., 1980. Directory of Germplasm Collections I. Food Legumes, IBPGR, Rome.
- Davies, D.R., Berry, G.J., Heath, M.C. & Dawkins, T.C.K., 1985. Pea (Pisum sativum L.). In: Summerfield, R.J. & Roberts, E.H. (Editors): Grain Legume Crops. Collins, London. p. 147-198.
Authors
- D.R. Davies
