Sorghum Diseases in India

Tagged plants were harvested at the end of
the growing season. Those tagged as diseased
with AW were cut and inspected for vascular
discoloration.
Plant height, panicle length, panicle mass,
grain mass, and 100-seed mass were measured.
Panicle exertion appeared to be affected by AW,
and it was also recorded. Seed number was calculated
from grain mass and 100-seed mass.
Panicle exertion was measured from base of the
flag leaf to base of the panicle.
Results
Paired-plant comparisons revealed that diseased
plants of BTx 623 suffered a 5% reduction in plant
height, had a 3% shorter panicle length, and a
52% shorter panicle exertion. They had 24%
fewer seeds, a 16% reduction in 100-seed mass,
and 36% lower yield (Table 2). Healthy plants
were superior in each of these parameters.
Table 2. Difference (%) between healthy and
acremonium wilt infected sorghum plants for
six parameters.
Maicillo
Parameter criollo BTx 623
Plant height
Grain yield
Grain head -1
Mass (100
grains)" 1
Panicle length
Panicle exertion
3 5**
33** 36**
26** 24**
9 16**
11* 3*
9 52**
*, ** Significant at 5% and 1%, in paired Wests.
Comparisons between acremonium-wilt and
healthy maicillo plants showed real differences in
only three of the six parameters. Panicle length
was reduced by 11% and seed number by 26%,
resulting in a yield reduction of 33%. MDM affected
maicillos, reducing plant height by 9%,
panicle length by 13%, seed number by 43%, 100seed
mass by 25%, and yield by 52% (Table 3).
Foliar Diseases on Landrace Cultivars
The sites selected in southern Honduras provided
differing prevalences of sorghum diseases
in farmers' fields. At the first, there was a severe
gray leaf spot (Cercospom sorghi) epidemic. The
second site was selected because only rust (Puccinia
purpurea) was observed, although it was at
a relatively low severity. A third site provided
an oval leaf spot (Ramulispora sorghicola) epidemic.
Materials and methods
Data collection was carried out between 12 and
17 Dec 1985, at various locations in Choluteca,
the Honduras. Plants were found at stages 11.2-
11.3 of Feekes' scale (Zadoks and Schein 1979).
At site 1, in El Rebase, many plants had 100%
gray leaf spot severity. At site 2, in Lajero Blanco,
the severity or rust was not as high as that of
gray leaf spot in site 1. At site 3, in La Joyada,
oval leaf spot predominated and many plants
had 100% leaf damage.
The parameters measured in the field were:
plant height, number of green leaves, leaf
length, leaf width, panicle length, and disease
Table 3. Means and differences for six parameters observed on 34 pairs of MDMV-diseased and
healthy plants of landrace sorghum cultivars, or "maicillos criollos."
Treatment
Healthy
Diseased
Difference
Difference (%)
Plant
height
318
290
28**
-9%
Panicle
exertion
(cm)
7.2
10.4
-32
31%
*, ** Significant at 5% and 1% in paired t-tests.
Panicle
length
25
22
3*
-13%
Grain
mass
23
11
12**
-52%
-(g)
100-seed Seed
mass number
(Ha)
2.1 1050
1.6 602
0.5** 448*
-25% -43%
307