Untitled - International Rice Research Institute
Untitled - International Rice Research Institute
Untitled - International Rice Research Institute
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Identification of fungi detected on rice seed<br />
The standard detection method used in identifying<br />
fungi on rice seed at IRRI is given below. Figure 3<br />
shows the parts of a rice seed attacked by fungi.<br />
With this method, numerous fungi have been detected<br />
on rice seed. The profile of each fungus detected<br />
is presented in the following pages.<br />
Methods and conditions of rice seed incubation<br />
for microorganism detection are listed below.<br />
The <strong>International</strong> Rules for Seed Testing recommend<br />
the blotter test for detecting seedborne fungi.<br />
The procedure involves these steps:<br />
1. Prepare materials (9.5-cm plastic petri dish,<br />
marking pencil, round blotter paper, distilled<br />
water, sampling pan, forceps, seed sample).<br />
2. Label plates accordingly using a marking<br />
pencil.<br />
3. Place 2–3 pieces of moistened round blotter<br />
paper in labeled plastic petri dishes.<br />
4. Sow 25 seeds per plate making sure that<br />
seeds are sown equidistantly with 15 seeds on<br />
the outer ring, 9 seeds at the inner ring, and 1<br />
seed in the middle.<br />
5. Incubate seeded plates at 21 °C under a 12-h<br />
light and 12-h dark cycle. Light sources can<br />
be near ultraviolet (NUV) light or daylight<br />
fluorescent tubes. The NUV light source can<br />
be a 320–400 nm lamp, preferably Philips<br />
TLD 36W/08 or GE F 40 BL. Daylight fluorescent<br />
tubes can be Philips TL 40W/54 day<br />
light or its equivalent.<br />
6. Examine each of the seeds after 5–7 d of<br />
incubation for fungal growth.<br />
Partition between<br />
lemma and palea<br />
Lemma<br />
Awn<br />
Sterile lemmas<br />
Palea<br />
Fig. 3. Parts of a rice seed.<br />
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