A manual of rice seed health testing - IRRI books - International Rice ...

Table 12.1. Weed seed Contaminants of rice encountered during dry seed inspection of incoming
seeds.
Family and
species
Seed description
Range of
detection
in incoming
seeds a
Sample of
country
in which
detected a
Figure
number
Asteraceae
Synedrella nodiflora
(L.) Gaertn.
Caryophyllacea
Stellaria media (L.)
Vill.
Cyperaceae
Cyperus compactus
Retz.
Cyperus iria L.
Fimbristylis miliaceae
(L.) Vahl
Scirpus juncoides
Roxb.
Scirpus sp.
Poaceae
Digitaria ciliaris
(Retz.) Koel.
Achenes black, achenes
of the tubular flowers
compressed, oblong, 4.5
x 1.1 mm, coarsely strigose,
the apex 2-awned,
2-3.5 mm long, strigose
Seed circular in outline
with marginal notch,
1-1.3 mm in diameter,
reddish brown, surface
covered with curved rows
of tubercles
Seed trigonous, oblong to
Iinear, slightly convex on
one side, apiculate
rostrate, brown,
1-2x0.5 mm
Seeds (achenes) brown
to red brown, egg
shaped, 1-1.5 mm long
and 0.1-0.5 mm wide with
large base and short
pointed minute tip
Seed (achene), inverted
egg-like, tip blunt,
pale ivory to brown,
finely reticulate,
0.6-1 mm long by
0.75 mm wide
Seed (achene) pale
brown to black, three
sided, almost smooth,
with minute tubercles,
up to 6 barbed
bristles originating
from the base, seed
about 2 mm long and
1.5-1.75 mm wide
Lower glume minute but
distinct, deltoid. 0-5-
2 mm long, upper glume
about 2/3 the length of
spikelet, narrow, with
1-mm-long marginal hairs
and 3 smooth nerves;
lemma broadly lanceolate,
as long as the spikelet
with 5-7 smooth nerves:
palea lanceolate, leathery
(coriaceous), pale green
to yellow brown, as long
as lemma; yellow-white
caryopsis tightly enclosed
by the lemma and palea,
generally elliptical and dorsally
compressed with a punctiform
hilum: embryo 0.6-0.8 mm by
0-.1%
0-.33%
.01-.1%
0-.04%
.1-.12%
.1-.12%
Nepal
Egypt
Bangladesh,
Madagascar,
China
Bangladesh
Bhutan, Nepal
Nigeria,
Vietnarn
Bangladesh
Bhutan, China,
India. Madagascar,
Malaysia, Nepal
Bangladesh,
Bhutan,
China (Taiwan),
India, Madagascar,
Malaysia,
Nepal
12.1
12.2
12.3
12.4
12.5
12.6
Weed seed contaminants 67