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Cajanus cajan (L.) Millsp.

Syn.: Cajanus indicus Spreng.
Fabaceae
Pigeon pea, Dhal, Gandul, Red gram, Congo pea, Gungo pea, No eye pea

Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.

  1. Uses
  2. Folk Medicine
  3. Chemistry
  4. Description
  5. Germplasm
  6. Distribution
  7. Ecology
  8. Cultivation
  9. Harvesting
  10. Yields and Economics
  11. Energy
  12. Biotic Factors
  13. References

Uses

Pigeon peas are popular food in developing tropical countries. Nutritious and wholesome, the green seeds (and pods) serve as vegetable. Ripe seeds are a source of flour, used split (dhal) in soups or eaten with rice. Dhal contains as much as 22% protein, depending on cv and location. Tender leaves are rarely used as a potherb. Ripe seeds may be germinated and eaten as sprouts. Plants produce forage quickly and can be used as a perennial forage crop or used for green manure. Often grown as a shade crop for tree crops or vanilla, a cover crop, or occasionally as a windbreak hedge. In Thailand and N. Bengal, pigeon pea serves as host for the scale insect which produces lac or sticklac. In Malagasy the leaves are used as food for the silkworm. Dried stalks serve for fuel, thatch and basketry. (Duke, 1981a).

Folk Medicine

Morton (1976) lists many folk medicinal uses for pigeon pea. In India and Java, the young leaves are applied to sores. Indochinese claim that powdered leaves help expel bladderstones. Salted leaf juice is taken for jaundice. In Argentina the leaf decoction is prized for genital and other skin irritations, especially in females. Floral decoctions are used for bronchitis, coughs, and pneumonia. Chinese shops sell dried roots as an alexeritic, anthelminthic, expectorant, sedative, and vulnerary. Leaves are also used for toothache, mouthwash, sore gums, child-delivery, dysentery. Scorched seed, added to coffee, are said to alleviate headache and vertigo. Fresh seeds are said to help incontinence of urine in males, while immature fruits are believed of use in liver and kidney ailments. (Duke, 1981a).

Chemistry

Analysis of dhal (without husk) gave the following values: moisture, 15.2; protein, 22.3; fat (ether extract), 1.7; mineral matter, 3.6; carbohydrate, 57.2; Ca, 9.1; and P, 0.26%; carotene evaluated as vitamin A, 220 IU and vitamin B1, 150 IU per 100 g. Sun-dried seeds of Cajanus cajan are reported to contain (per 100 g) 345 calories, 9.9% moisture, 19.5 g protein, 1.3 g fat, 65.5 g carbohydrate, 1.3 g fiber, 3.8 g ash, 161 mg Ca, 285 mg P, 15.0 mg Fe, 55 mg b-carotene equivalent, 0.72 mg thiamine, 0.14 mg riboflavin, and 2.9 mg niacin. Immature seeds of Cajanus cajan are reported to contain per 100 g, 117 calories, 69.5% moisture, 7.2 g protein, 0.6 g fat, 21.3 g total carbohydrate, 3.3 g fiber, 1.4 g ash, 29 mg Ca, 135 mg P, 1.3 mg Fe, 5 mg Na, 563 mg K, 145 mg b-carotene equivalent, 0.40 mg thiamine, 0.25 mg riboflavin, 2.4 mg niacin, and 26 mg ascorbic acid/100 g. Of the total amino acids, 6.7% is arginine, 1.2% cystine, 3.4% histidine, 3.8% isoleucine, 7.6% leucine, 7.0% lysine, 1.5% methionine, 8.7% phenylalanine, 3.4% threonine, 2.2% tyrosine, 5.0% valine, 9.8 aspartic acid, 19.2% glutamic acid, 6.4% alanine, 3.6% glycine, 4.4% proline, 5.0% serine with 0 values for canavanine, citrulline and homoserine. Methionine, cystine, and tryptophane are the main limiting amino acids. However, in combination with cereals, as pigeon peas are always eaten, this legume contributes to a nutritionally balanced human food. The oil of the seeds contains 5.7% linolenic acid, 51.4% linoleic, 6.3% oleic, and 36.6% saturated fatty acids. Seeds are reported to contain trypsin inhibitors and chymotrypsin inhibitors. Fresh green forage contains 70.4% moisture, 7.1 crude protein, 10.7 crude fiber, 7.9 N-free extract, 1.6 fat, 2.3 ash. The whole plant, dried and ground contains 1,1.2% moisture, 14.8 crude protein, 28.9 crude fiber, 39.9 N-free extract, 1.7 fat, and 3.5 ash. (Duke, 1981a).

Description

Perennial woody shrub, mostly grown as an annual for the legume; stems strong, woody, to 4 m tall, freely branching; root system deep and extensive, to about 2 m, with a taproot. Leaves alternate, pinnately trifoliolate, stipulate; stipels small, subulate; leaflets lanceolate to elliptic, entire, acute apically and basally, penninerved, resinous on lower surface and pubescent, to 15 cm long and 6 cm wide. Inflorescence in terminal or axillary racemes in the upper branches of the bush. Flowers multi-colored with yellow predominant, red, purple, orange occur in streaks or fully cover the dorsal side of the flag, zygomorphic. Pods compressed, 2–9-seeded, not shattering in the field. Seeds lenticular to ovoid, to 8 mm in diameter, about 10 seeds per gram, separated from each other in the pod by slight depressions. Germination cryptocotylar. (Duke, 1981a).

Germplasm

Many cvs differ in height, habit of growth, color of flower, time of maturity, color, and shape of pods, and color, size, and shape of seed. Perennial types assume a tree-like appearance, yield well the first year but poorer in later years; suitable for forage, cover purposes, shade and for hedge plants. Annual (weak perennial) types are small plants grown as field crops, mainly cultivated for seed purposes, with very good quality white-seeded cvs ('Gujerat' in Ceylon) and red-seeded cvs (common in areas south of Bombay). Also in India and Ceylon the cvs 'Tur 5' and 'Tenkasi' are extensively grown. High-yield, short-duration Indian cvs include 'Co-l', 'Kanke 3', 'Kanke 9', 'Makta', 'Pusa ageta', 'Sharda', 'T-21', and 'UPAS-120'. In Florida day-neutral 'Amarillo' can be sown and harvested at different times throughout the year. Other good cvs are 'Morgan Congo', 'Cuban Congo' and 'No-eye Pea'. Of the better yielding cvs in trials in Uganda 'CIVE1', 'UC948', 'UC2288', 'UC3035' and 'UC16' are "spray types" where secondary branches are almost as long as the main stem, and there are few tertiaries; 'UC1377' and 'UC959' are "bush types". Assigned to the Hindustani and African Centers of Diversity, pigeon pea or cvs thereof is reported to exhibit tolerance to disease, drought, frost, high pil, laterite, low pH, nematodes, photoperiod, Salt, sand, virus, waterlogging, weed, wilt, and wind. (2n = 22, 44, 66). (Duke, 1981a).

Distribution

Probably native to India, pigeon pea was brought millennia ago to Africa where different strains developed. These were brought to the new world in post-Columbian times. Truly wild Cajanus has never been found; they exist mostly as remnants of cultivations. In several places Cajanus persists in the forest. The closest wild relative, Atylosia cajanifolia Haines, has been found in some localities in East India. Most other Atylosias are found scattered throughout India, while in North Australia a group of endemic Atylosia species grow. In Africa Cajanus kerstingii grows in the drier belts of Senegal, Ghana, Togo, and Nigeria. Pigeon peas occur throughout the tropical and subtropical regions, as well as the warmer temperate regions (as North Carolina) from 30°N to 30°S (Duke, 1981a).

Ecology

Pigeon pea is remarkably drought resistant, tolerating dry areas with less than 65 cm annual rainfall, even producing seed profusely under dry zone conditions, as the crop matures early and the incidence of pest damage is low. Pigeon pea is more or less photoperiod-sensitive; short days decrease time to flowering. Under humid conditions pigeon pea tends to produce luxuriant vegetative growth, rain during the time offlowering causes defective fertilization and permits attack by pod-caterpillars. Annual precipitation of 6–10 dm is most suitable, with moist conditions for the first two growing months, drier conditions for flowering and harvest. Growing best under temperatures of 18–29°C, some cvs will tolerate 10°C under dry conditions and 35°C under moister conditions. The plant is sensitive to waterlogging and frost. It will grow in all types of soils, varying from sand to heavy clay loams, well-drained medium heavy loams being best. Some cvs tolerate 6–12 mmhos/cm salinity. Ranging from Warm Temperate Moist to Wet through Tropical Desert to Wet Forest Life Zones, pigeon pea has been reported to tolerate annual precipitation of 5.3–40.3 dm (mean of 60 cases 14.5 dm), annual mean temperature of 15.8–27.8°C (mean of 60 cases = 24.4°C), and pH of 4.5 to 8.4 (mean of 44 cases = 6.4). (Duke, 1981a).

Cultivation

Seeds are sown where desired, in pure stands at about 9–22 kg/ha for rows, but sometimes it is broadcast. Seed germinate in about 2 weeks. Quite frequently (in India) pigeon pea is grown mixed with other crops or grown in alternate rows with rows of sorghum, groundnuts, sesame, cotton, pineapples, millets or maize. For pure crops pigeon pea should be sown 2.5–5 cm deep in rows 40–120 cm by 30–60 cm. When sown as a mixture, it should be sown in widely spaced rows ranging from 1.2–2.1 m depending on the associated crop. About 3–4 seeds may be planted in each hill, and later thinned to 2 plants per hill. Plants show little response to fertilizers, e.g., mixed plantings with millet in India showed negative response to N. For the first month, pigeon pea shares the intercultivation of the main crop. In the tropics, 20–100 kg/ha phosphoric acid are recommended. S, with or without P, can significantly increase seed yield and nitrogen fixation. Early cvs start podding in 12 weeks but maturation requires 5–6 months. Late cvs require 9–12 mos. The crop may be ratooned for forage or let persist for 3–5 years. Seed yields drop considerably after the first year, and disease build-up may reduce stand.

Harvesting

In India pigeon peas are sown in June–July. Annual medium and late cvs flower in January and yield a first crop in March–April (North India). Early and medium cvs flower in October–November, yielding in December–January (Central and South India). Very early cvs have not been widely accepted. In East Africa harvests are taken in June–July. In the Caribbean areas, green pods are harvested for home consumption or canning. Caribbeans have developed dwarf cvs with more uniform pod maturity which are mowed and threshed with a combine harvester. Depending on the cv, the location and time of sowing, flowering can occur as early as 100 to as late as 430 days. In harvesting a first crop it may be necessary to pick the pods by hand. Mature crop is harvested by cutting the whole plant with a sickle. Cut plants, often still with green leaves are dried in the field. Threshing by wooden flails or trampling is carried out on threshing floors. Grain is then cleaned by winnowing. Mechanical threshing and seed cleaning is possible.

Yields and Economics

Green-pod yields vary from 1,000 to 9,000 kg/ha. Dried seed yields may reach 2,500 kg/ha in pure stands, but average yields are closer to 600 kg/ha. Of seven promising cvs in Uganda, 'CIVE1' yielded 889 kg seed/ha with a grain/straw ratio of 0.318, '16' on the other hand with the highest seed yield of 1,225 kg/ha had a grain/straw ratio of only 0.224 (Khan and Rachie, 1972). India's pigeon pea production, 1,818,000 MT from 2,540,000 hectares (1975) is greater than that of any other country. Pigeon pea is cultivated commercially (for canning) in the Dominican Republic, Trinidad, Puerto Rico, and Hawaii; Africa, Kenya, Malawi, Tanzania, and Uganda grow it mostly for home consumption. Elsewhere in the tropics it is more a crop of kitchen gardens and hedges. In 1975, Asia led world production, 1,845,000 MT, averaging 706 kg/ha, Africa produced 70,000 MT averaging 406 kg/ha, North America produced 41,000 MT, averaging 1,415 kg/ha, South America produced 4,000 MT averaging 449 kg/ha. India was the leading producer country, with 1,818,000 MT, but averaged only 716 kg/ha, as compared with the Dominican Republic where yields were reported at 2,194 kg/ha (FAO, 1975a). However, the Indian yields are dry seed while the Dominican yields are fresh seeds or pods (Duke, 1981a).

Energy

Experimental yields have exceeded 2,500 kg/ha. Grain:straw ratios are reported to range from 0.224 to 0.318 (Duke, 1981b), suggesting that a straw factor of 3 be used in phytomass calculations. Biomass yields of 7 MT/ha are reported in Florida, 12 MT/ha in Cuba, while 2 MT of woody stalks used as fuel is obtained per hectare in a growing season in India (NAS, 1980a). There in India, the spindly stalks are extensively used as a cooking fuel, just as they are in Malawi. Historically, the stalks were employed to make the charcoas used in gunpowder.

Biotic Factors

Many fungal diseases (31), involving 45 pathogens, are known; the most serious is wilt disease (Fusarium udum), favored by soil temperatures of 17°–20°C. The fungus enters the plant through the roots and may persist in soilborne stubble for a long time. The only effective control measure is development of resistant cvs (e.g., 'C-ll,' 'C-36,' 'NP-15,' 'NP-38,' and 'T-17'). Rotation with tobacco and intercropping with sorghum is said to decrease the wilt problem. Other fungi include: Cercospora spp., Colletotrichum cajanae, Corticium solani, Diploidia cajani, Leveillula taurica, Macrophomina phaseoli, Phaeolus manihotis, Phoma cajani, Phyllosticta cajani, Phytophthora sp., Rhizoctonia bataticola, Rosellinia sp., Sclerotium rolfsii, and Uredo cajani (rust). So far, economic damages by these have been small or negligible, but rust is locally of some importance. Pigeon pea is also attacked by the bacterium Xanthomonas cajani and the sterility mosaic and yellow mosaic viruses. Sterility mosaic is being recognized as a serious economic threat. Of minor importance are the nematodes isolated from pigeon pea. They include: Helicotylenchus cavevessi, H. dihystera, H. microcephalus, H. pseudorobustus, Heterodera spp., H. cajani, H. trifolii, Hoplolaimus indicus, Meloidogyne hapla, M. incognita acrita, M. javanica, M. javanica bauruensi, Pratylenchus spp., Radopholus similis, Rotylenchulus reniformis, Scutellonema bradys, Scutellonema clathricaudatum, Trichodorus mirzai, Tylenchorhynchus brassicae, T. indicus, Xiphinema campinense, and X. ifacolum. Damage caused by insect pests is a major constraint on yield in most areas. Few of the more than 100 species of insects recorded as damaging the crop in India can be regarded as major pests. The podborer, Heliothis zea, is commonly regarded as the key pest throughout Africa and Asia. It is particularly damaging on early formed pods. In many parts of India the podfly, Melanagromyza obtuse, takes over as the dominant pest later in the season. In some areas, a newly recognized hymenopteran pest, Tanaostigmodes, can also cause extensive pod damage late in the season. Pests which can be locally or seasonally important are plume moth (Exelastis atomosa), blue butterfly (Euchrysops cnejus), leaf tier (Eucosma critica), bud weevil (Ceutorhynchus aspurulus), spotted podborer (Maruca testulalis), pea podborer (Etiella zinckenella) and bugs (Clavigralla spp.). A blister beetle (Mylabris pustulata) which destroys flowers can be a spectacular but localized pest. Thrips (Frankliniella schultzei, Megalurothrips usitatus) may cause premature flower drop. In general, the determinate (clustering) plants lose more to lepidopterous borers while podfly causes more damage to the later indeterminate cvs. The indeterminate cvs have a greater compensatory potential and, where the pests are not controlled, commonly yield more than the clustering types. In the West lndies, the leafhopper Empoasca fabilis is combatted with malathion while podborers Ufa rubedinela, Ancylostomia stercorea, and Heliothis virescens are combatted with DDT, Dipterex and Gardona. In Trinidad the black aphid Aphis craceivora may develop heavy infestations. Bruchids (Callosobruchus spp.) attack the crop in the fields and then build up in stored pods or seeds. The use of insecticides is feasible, but as yet uneconomic. A few farmers use insecticides; DDT is still the most effective and least expensive. During its first 60 days, pigeon pea requires weed control. Preemergence chloramben, though effective, may slightly damage the crop. In the West Indies, 1) preemergence prometryne with post-emergence paraquat spray, 2) alachlor plus linuron, and 3) terbutryne up to 9 weeks after application, have proven useful in weed control (Duke, 1981a).

References

Complete list of references for Duke, Handbook of Energy Crops
Last update Tuesday, December 30, 1997