Sorghum Diseases in India

Rust
Rust (Puccinia purpurea) is also becoming an important
sorghum disease in Brazil. Preliminary
tests in greenhouse conditions and field observations
from the National Sorghum Uniform
Disease Nursery suggest the existence of races
of P. purpurea in Brazil Changes in reaction of
some cultivars, such as Brandes (BR 501), with
time indicate this possibility A high degree of
'"slow rusting" has been detected on some sorghum
genotypes in Brazil.
A natural infection method is used in the
field to determine degrees of resistance to sorghum
rust. The cultivar Theis is used in the
spreader row. The interplot interference between
screening plots is reduced by using border
rows of a resistant cultivar, such as SC 326-6
(Fig. 2). The disease intensity in each cultivar is
scored at three points in the screening plot at 7or
15-day intervals according to a standard disease
scale. The data of each genotype, similar to
the leaf anthracnose screening procedure, are
transformed to AUDPC The AUDPC values for
some experimental hybrids and varieties in Brazil
are presented in Table 4.
Table 4. Area under rust progress curves of 14 sorghum cultivars, evaluated under decreasing levels
of inoculum at 0.5 m, 3 m, and 5.5 m from a spreader row. 1
Table 4. Area under rust progress curves of 14 sorghum cultivars, evaluated under decreasing levels
of inoculum at 0.5 m, 3 m, and 5.5 m from a spreader row. 1
AUDP curve
Distances, from susceptible border row
Cultivar Pedigree (0.5 m) (3.0 m) (5.5 m)
CMSXS 351 BR 007A x CMSXS 178 911.5a 698.0a 658.3a
BR 001 778.2b 558.5b 638.3a
BR 302 BR 001AxBR 011R 757.7bc 593.0b 524.0b
BR 008 695.0c 331.0c 238.3c
SC 112-14 603.3d 279.0d 192.0d
CMSXS 180 BRP 3 R x SC 326-6 524.0e 69.5f 42.8f
CMSXS 354 BR 008 Ax CMSXS 179 382.7f 122.0e 58.2c
CMSXS 179 BRP 3 R x SC 326-6 262.0g 42.0fg 31.5efg
CMSXS 359 CMSXS 156 x CMSXS 180 104.0h 31.0fg 10.5g
CMSXS 181 BRP 3 R x SC 326-6 15.7hi 31.5fg 17.5fg
CMSXS 156 60.7hi 10.5g 10.5g
CMSXS 182 BRP 3 R x SC 326-6 33.7i 10.5g 10.5g
CMSXS 178 SC 326-6 x SC 748-5 32.3i 10.5g 10.5g
CMSXS 157 21.0i 10.5g 10.5g
1. Values in the same column followed by different letters are significantly different (P = 0.05) according to
60
Duncan's Multiple Range test.
1. Theis (BR 503)
2. SC 326-6 (BR 005)
Figure 2. Diagram of field plots used to evaluate
resistance to rust in field conditions under
a disease gradient.
Charcoal rot
Resistant 2
Cultivar
Resistant
Cultivar
Resistant
1.0 m 5.0 m
8.0 m
1.0 m
Sorghum charcoal rot (Macrophomina phaseolina)
has been observed in the semi-arid regions of
Brazil (northeastern Brazil), where the water