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 ...
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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