Coix lacryma-jobi L.

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Graminae

Common names

Job's tears (Australia), adlay (Philippines), sila (Fiji), ma yuen (China).

Description

An annual, 1-2 m tall, stem erect, with brace-roots from the lower nodes. Inflorescences prolific; the first glume of the male spikelet narrowly winged, the wings not covering the raceme (Henty, 1969). Seeds yellow, purple, white or brown. The grass is monoecious with separate male and female flowers. There are soft-shelled forms for eating and hard-shelled ones for ornamentation.

Distribution

Native to tropical Asia, but now widely distributed in the tropics.

Season of growth

Summer.

Altitude range

Sea-level to 2 000 m.

Rainfall requirements

It needs reasonably high rainfall in areas which grow maize and upland rice, usually in excess of 1 500 mm.

Drought tolerance

It is not tolerant of drought.

Soil requirements

It requires a fertile soil for its best growth. In poor soils many of the fruits are hollow.

Ability to spread naturally

It spreads very slowly in favourable environments.

Land preparation for establishment

It prefers a well-prepared seed-bed.

Sowing methods

It is sown by seed. Drill it in with a machine able to handle large seeds or, by hand, dig holes with a hoe and plant at distances of 40-60 cm.

Sowing depth and cover

The seed is sown 5 cm deep and covered.

Sowing time and rate

It is sown at the beginning of the wet season at 10-15 kg/ha.

Dry-matter and green-matter yields

In India it is grown as a fodder plant in low-lying areas, and its average yield of green material is about 13.9 t/ha (Bor, 1960). For grain it yields 2 000-4 000 kg husked grain per hectare. The hulling percentage is 30-50 percent.

Cultivars

  • 'Stenocarpa' Stapf Hook. 
the false fruits are more or less cylindrical.
  • 'Agrestis' (Lour.) Backer 
the false fruits are ovoid-globose (Henty, 1969).
  • 'Lacrymajobi' 
the involucres are ovoid, hard and polished.
  • 'Ma-yuen' 
in Malaysia the involucres are ovoid, soft, shell-like and striate. A third Malaysian variety, cv. Monilifer, has longer often globose involucres 7-10 mm in diameter, stony and flattened on one side (Gilliland et al., 1971).

Latitudinal limits

About 22°N and S.

Palatability

The green material is very palatable.

Response to photoperiod

Its flowering is accelerated by short days (Evans, Wardlaw & Williams, 1964).

Chemical analysis and digestibility

Fresh early vegetative growth in India showed 29.9 percent dry matter, 8.5 percent crude protein, 27.9 percent crude fibre, 8.96 percent ash, 2.7 percent ether extract and 51.9 percent nitrogen-free extract (Sharma et al., 1968). The husked grain contains 10.8 percent moisture, 13.6 percent protein, 60 percent fat, (ether extract), 58.5 percent carbohydrate (nitrogen-free extract), 8.4 percent fibre and 2.6 percent ash.

Natural habitat

Swampy places and near streams, cultivated.

Tolerance to flooding

It is tolerant to flooding and is found occurring naturally in swamps.

Fertilizer requirements

It needs a fertile soil or a dressing with complete fertilizer.

Genetics and reproduction

2n=10, 20 (Fedorov, 1974).

Economics

A tall grass which is cultivated in many parts of the tropics, particularly among the hill-tribes who make a porridge and also brew beer from it. The soft-shelled races are cultivated for these purposes but the hill tribes also cultivate several hard-shelled varieties which are used for beads and other ornaments (Bor, 1960). The ground grain is used as feed for poultry. It is grown to a limited extent in south-eastern Asia. Although it has been tried elsewhere, production is still very small.

Further reading

Schaffhausen, 1952.