Coix lacryma-jobi (PROSEA)
- Protologue: Sp. pl.: 972 (1753).
- Family: Gramineae
- Chromosome number: 2n= 4x= 20
- Coix lacryma L. (1759),
- C. agrestis Lour. (1790),
- C. arundinacea Lamk (1791).
- Job's tears, adlay (En)
- Larmes de Job, larmilles, herbe à chapelets (Fr)
- Indonesia: jali, jali betul, jali watu
- Malaysia: jelai batu, jelai pulut, menjelai
- Philippines: adlai (Bisaya), kaudlasan (Tagalog), katigbi (Tagalog)
- Cambodia: skuöy
- Laos: düay
- Thailand: duai (general), maduai (northern)
- Vietnam: ý dĩ, bo bo, cườm gạo.
Note: The Arabs, who introduced the plant to the West, named it "Damu Ayub" (Job's tears), because its false fruit resembles a tear-drop. This name has been adopted in several other languages.
Origin and geographic distribution
The origin of Job's tears is unknown, but it is indigenous to southern and eastern Asia. The form with soft-shelled false fruit (var. ma-yuen (Romanet) Stapf) has been cultivated since ancient times - 3000-4000 years ago in India, 2000 years ago in China - and was very important before maize and rice became widespread staple foods. At present it is cultivated as a minor cereal crop throughout the tropics and subtropics, especially in India, China, the Philippines, Thailand, Malaysia and the Mediterranean. Forms with hard-shelled false fruit are also occasionally cultivated. Plants escaped from cultivation occur as weeds.
The form with soft-shelled false fruit (var. ma-yuen) can be easily husked and has large kernels which are eaten in the same way as rice, alone or mixed with it. They can be substituted for rice in all foodstuffs. In Malaysia the grain is roasted before husking and then used in porridge and in cakes. In Thailand it is also often used in the preparation of sweets and sometimes in soups and other foods.
Dough made from the flour will not rise because of the absence of gluten. A good mixture for bakery purposes is 70% wheat and 30% Job's tears.
The raw kernel tastes sweet and is often eaten as a snack. Both alcoholic and non-alcoholic drinks are prepared from it. In Japan a kind of tea, called "dzu", is made from the parched grain. A beer made from the pounded grain is popular among Indian hill tribes and in the Philippines.
The whole grain is fed to poultry and the flour can replace maize flour in poultry feed. Outside Asia, Job's tears is mainly cultivated as a fodder, especially for cattle and horses. It is suitable for silage. Straw and leaves are used for thatching.
The grain and flour are very digestible and are believed to have medicinal value. Therefore, they are given to people in weak condition; in Vietnam they are considered beneficial to the lungs. The roots in particular are applied for medicinal purposes, a decoction of them being used as a vermifuge in China and to treat gonorrhoea in the Philippines. In India the roots, together with parts of other plants, are used against a wide range of ailments, e.g. against menstrual disorders.
Almost everywhere where Job's tears grows, the attractive, hard-shelled false fruits of the wild forms are used for necklaces, rosaries, bead curtains and the like. The whole inflorescence is sometimes used in dried flower arrangements.
Production and international trade
Job's tears is mainly used and traded locally only. It is often considered as a reserve food in times of scarcity. Recent data on production and cultivated acreage are very scarce. A 1985 study on the Iban hill farming system in Sarawak concluded that 55% of the households cultivated Job's tears but seldom on more than 10% of the farm area.
In Thailand the production areas are found in the north and north-east but no exact data are available. About 4000-6000 t of grain are exported to Japan and Taiwan yearly.
Per 100 g edible portion the husked grain of Job's tears contains: water 10.1-15.0 g, protein 9.1-23.0 g, fat 0.5-6.1 g, carbohydrates 58.3-77.2 g, fibre 0.3-8.4 g, ash 0.7-2.6 g. The energy value is about 1500 kJ/100 g. Job's tears is a nutritious grain, containing more fat and protein than rice and wheat. The root contains coixol which is analgesic and sedative.
The 1000-seed weight is 80-90 g.
- Erect, perennial, strongly tillering, monoecious grass, often cultivated as an annual, up to 3 m tall.
- Culm filled with pith, glabrous, sometimes pruinose, branched in the upper part.
- Leaves large and sheathed; sheath short, glabrous or with long hairs at the apex; ligule short and membranous; auricles absent; blade linear to ovate-lanceolate, 8-100 cm × 1.5-5 cm, base rounded to almost cordate, apex acute, midrib prominent, margins rough, smooth or scabrid above.
- Inflorescence in axil of upper leaves, solitary or 2-7-fascicled, on peduncle 3-6 cm long; at the end of the peduncle a hollow, bony, globular to ovoid-elliptical cupule (a modified leaf-sheath), 5-15 mm long, shiny, white or blueish, comprising 2 racemes; female raceme enclosed by the cupule and consisting of a sessile spikelet accompanied by 2 barren pedicels; spikelet with 1 pistillate floret of which the 2 stigmas exsert from the mouth of the cupule; male raceme 3-5 cm long, exserted from the mouth of the cupule, with about 10 imbricate spikelets borne in pairs or threes, one pedicelled, the other(s) sessile; spikelet lanceolate to ellipsoid, 7-8 mm long, falling at maturity, containing 1-2 staminate florets, each with a lemma, a smaller palea and 3 stamens.
- False fruit (the cupule) variable in size, shape, colour and hardness, usually 8-12 mm long, grey, yellow-brown or purplish, soft or hard, containing the caryopsis.
- Caryopsis dark red in hard-shelled forms, pale brown in soft-shelled edible forms.
Growth and development
Job's tears takes about 1-2 weeks to germinate, depending on the moisture content of the soil. The plant does not grow very fast; normally it requires at least 4 months of vegetative growth before it starts to flower. After flowering (and cross pollination) the crop needs about two months for grain filling. The crop is ready for harvest about 7 months from sowing. When most of the seeds are ripe, the plant starts to dry.
Other botanical information
The genus Coix L. is now considered to comprise 4 closely related species, all occurring in South-East Asia, while some have also been introduced elsewhere:
- C. aquatica Roxb. (synonym: C. lacryma-jobi L. var. aquatica (Roxb.) Watt): a weed of ponds and lakes, sometimes used as fodder;
- C. gigantea Koenig ex Roxb. (synonyms: C. lingulata Hack., C. lacryma-jobi L. var. palustris (Koorders) Backer): a weed of moist or dry locations, erect, sometimes collected for food, false fruit often used for ornamental purposes;
- C. puellarum Balansa (synonym: C. lacryma-jobi L. var. puellarum (Balansa) A. Camus): a perennial occurring in India, Burma (Myanmar), Indo-China and Peninsular Malaysia, used for ornamental purposes;
- C. lacryma-jobi L. Mainly based on characteristics of the false fruit, 4 varieties are distinguished:
- var. lacryma-jobi : false fruit ovoid, 8-12 mm × 6-8 mm, hard, not striate; usually collected from the wild, sometimes cultivated for food or ornaments (necklaces); it is the commonest (wild) type, distributed pantropically; many medicinal uses;
- var. monilifer Watt: false fruit globose, 7-10 mm in diameter, flattened on one side, hard, not striate; a rare type, only known from Burma (Myanmar) and eastern India; uses unknown, but could be ornamental;
- var. stenocarpa Stapf (synonyms: C. stenocarpa (Stapf) Balansa, C. tubulosa Hack. ex Warb.): false fruit cylindrical or roughly bottle-shaped, hard, not striate; mainly grown as an ornamental;
- var. ma-yuen (Romanet) Stapf (synonyms: C. ma-yuen Romanet, var. frumentacea Makino): false fruit ovoid to pyriform, 8-12 mm long, quite soft, striate, shell-like; cultivated pantropically mainly for its edible false fruit as a cereal, and most information presented here concerns this variety; many local (unnamed) landraces exist; in Thailand glutinous and non-glutinous cultivars exist; in Brazil a high-yielding, early-maturing dwarf form with brown elongated false fruit has been selected.
Job's tears is a quantitative short-day plant and requires high temperatures, abundant rainfall, reasonably fertile soils, and prefers short, sunny days. In the tropics it occurs up to 2000 m altitude. It often grows wild in swampy locations.
Job's tears is usually propagated by seed (caryopsis). If not stored well, seed will quickly lose its viability under warm humid conditions. Seed is sown by dibbling, 5 cm deep, at the start of the rains, after ploughing or hoeing the field. Row spacing is 40-80 cm, the seed rate 7-15 kg/ha. When cultivated as an intercrop, it is sown at random or plants are grown along field borders. Propagation by cuttings is possible and recommended for fodder production. Propagation by seed gives deeper rooting, and, consequently, better drought tolerance and higher seed yield.
Weeding is necessary up to 60 days after sowing or until Job's tears has reached a plant height of 40 cm. In general, plants are not given much care, but when young they need abundant water. They respond well to application of manure; chemical fertilizers or insecticides are not used.
Diseases and pests
Job's tears is relatively little affected by diseases and pests. The most serious disease is smut (Ustilago coicis) which destroys the ovaries; it severely damages crops in Thailand, that is why it is recommended to treat seed with a fungicide or with hot water (60-70°C) for at least 10 minutes before sowing. Tar leaf spot (Phyllachora coicis) has also been reported from Thailand. Other diseases which may occur are rust (Puccinia operata) and Ustilago lachrymae-jobi.
Rats, birds and sometimes grasshoppers and termites may cause considerable losses.
Job's tears can be harvested 4-8 months after sowing, depending on the cultivar and the season. Usually, whole plants are cut at the base when the grain is ripe. The stubble can be left in the field and will then tiller again. The new fresh leaves are an excellent fodder. In Thailand the crop is harvested with a sharp knife by cutting the top of the plant which bears the infructescences. In some cases (Malaysia) the stems are snapped first, to accelerate drying.
Normal yield of husked grain varies from 2-4 t/ha. The hulling percentage is 30-50%. If cultivated for fodder, several cuts per year are possible.
Handling after harvest
After threshing and husking, which is done manually or with the same tools as for rice, the grain is dried on mats in the sun. Under humid conditions, the storability of the grain is limited, but is better for whole than for husked grain.
There is considerable variation in cultivated and wild Job's tears. The greatest variation in wild forms can be found in India and Burma (Myanmar), and in cultivated Job's tears in Indo-China. During 1983-1984, edible forms of C. lacryma-jobi were collected in Thailand and stored at the National Genebank of Thailand.
In the course of time, Job's tears has been selected by farmers for easy husking, resulting in var. ma-yuen. However, the crop has a relatively long growing season, shows uneven ripening and variable yields. Nevertheless, large variation in Job's tears offers opportunities for breeding programmes. In Thailand, breeding work is being carried out to obtain resistance against smut disease. In Japan selection work focuses on the use as a fodder. In Brazil, a promising high-yielding "dwarf" cultivar, probably introduced from Japan, has been selected and distributed.
Although enjoyed locally by many people, Job's tears is still decreasing in popularity in favour of higher-yielding cereals, mainly maize and rice. However, it has some advantages over these other cereals. It is less susceptible to diseases and pests, it can be grown where other crops are difficult to cultivate, and it does not need much care. Furthermore, it is more nutritious. In spite of these advantages, hardly any research attention has so far been given to Job's tears. Therefore at this stage it is most important to conserve the great diversity in germplasm collections.
Promising research on the crop as a fodder is in progress in Japan and Africa.
- Arora, R.K., 1977. Job's tears (Coix lacryma-jobi) - a minor food and fodder crop of Northeastern India. Economic Botany 31(3): 358-366.
- Cramb, R.A., 1985. The importance of secondary crops in Iban hill rice farming. Sarawak Museum Journal 34(55): 37-45.
- Jain, S.K. & Banerjee, D.K., 1974. Preliminary observations on the ethnobotany of the genus Coix. Economic Botany 28(1): 38-42.
- Koul, A.K., 1974. Job's tears. In: Hutchinson, J. (Editor): Evolutionary studies in world crops. Cambridge University Press, United Kingdom. pp. 63-66.
- Naku Mbumba, M.D., Walangululu, M. & Basiloko, M., 1984. Comportement des plants issus de différents modes de propagation du coix [The behaviour of Coix plants derived from various propagation methods]. Tropicultura 2(3): 95-98.
- Sukhapinda, K. et al., 1985. Collection of maize and coix in Thailand. Newsletter International Board for Plant Genetic Resources (IBPGR), Regional Committee for Southeast Asia 9(2): 11-13.
- Vacharotayan, S., Jan-orn, J., Charoen, P., Titatarn, S. & Kingkaew, S., 1982. Job's tears production and marketing in Thailand. JETRO Japan Trade Centre, Bangkok, Thailand.
- von Schaaffhausen, R., 1952. Adlay or Job's tears - a cereal of potentially greater economic importance. Economic Botany 6: 216-227.
- M.H. van den Bergh & N. Iamsupasit