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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
the false fruits are more or less cylindrical.
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'Agrestis' (Lour.) Backer
the false fruits are ovoid-globose (Henty, 1969).
the involucres are ovoid, hard and polished.
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.
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