26.01.2015 Views

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

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

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

SHOW MORE
SHOW LESS
  • No tags were found...

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

Table 10.2. continued<br />

Disease<br />

Fungi<br />

Growth stage at which<br />

inspection is made a<br />

Scale (degree <strong>of</strong> severity)<br />

Scale (for blast nursery)<br />

(Note: scale 1-4 is qualitative,<br />

5-9 is quantitaitve).<br />

Note: Lesion types 5,7, and 9<br />

are considered typical susceptible<br />

lesions.<br />

Panicle blast (PB)<br />

Pathogen: P. oryzae<br />

Note: For the mass evaluation<br />

<strong>of</strong> PB incidence, count<br />

only the number <strong>of</strong> panicles<br />

with lesions completely around<br />

node, neck, or lower part <strong>of</strong><br />

panicle axis (symptom type 7-9).<br />

8 (20-25 d<br />

after heading)<br />

8-9<br />

5 Narrow or slightly elliptical<br />

lesions, 1-2 mm long with brown<br />

margin<br />

7 Broad, spindle-shaped lesions<br />

with yellow, brown, or purple<br />

margin<br />

9 Rapidly coalescing small, whitish,<br />

grayish, or bluish lesions without<br />

distinct margins<br />

Scale (based on symptoms)<br />

0 No visible lesion or lesions on<br />

only a few pedicels<br />

1 Lesions on several pedicels or<br />

secondary branches<br />

3 Lesions on a few primary<br />

branches or the middle part <strong>of</strong><br />

panicle axis<br />

5 Lesion partially around the<br />

panicle base (node) or the uppermost<br />

internode or the lower part<br />

<strong>of</strong> panicle axis near the base<br />

7 Lesion completely around panicle<br />

base or uppermost internode or<br />

panicle axis near the base with<br />

more than 30% <strong>of</strong> filled grain<br />

9 Lesion completely around panicle<br />

base or uppermost internode or<br />

panicle axis near base with less<br />

than 30% <strong>of</strong> filled grains<br />

Scale (incidence <strong>of</strong> severely infected<br />

panicles)<br />

0 No incidence<br />

1 Less than 5%<br />

2 5-10%<br />

5 11-25%<br />

7 26-50%<br />

9 More than 50%<br />

Brown spot (BS)<br />

Pathogen:<br />

Cochliobolus miyabeanus<br />

( Bipolaris oryzae, Drechslera<br />

oryzae )<br />

Note: This scale may also be used<br />

to assess eyespot disease caused by<br />

D. gigantea.<br />

Narrow brown leaf spot (NBLS)<br />

Pathogen: Sphaerulina oryzina<br />

( Cercospora janseana )<br />

2 and<br />

5-9<br />

3-9<br />

Scale (affected leaf area)<br />

0 No incidence<br />

1 Less than 1%<br />

2 1-3%<br />

3 4-5%<br />

4 6-10%<br />

5 11-15%<br />

6 16-25%<br />

7 26-50%<br />

8 51-75%<br />

9 76-100%<br />

Scale (affected leaf area)<br />

0 No incidence<br />

1 Less than 1%<br />

3 1-5%<br />

5 6-25%<br />

7 26-50%<br />

9 51-100%<br />

Field inspection 53

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!