Sorghum Diseases in India

60
45
30
15
0
30
15
0
30
15
(R)
(M)
(S)
0
5 15 25 35 45 55
Time after anthesis (days)
Figure 12. Free caffeic acid in sorghum caryopses
that were inoculated with F. moniliforme
at anthesis and evaluated during
caryopsis development. Legend: (See Fig. 7).
Water begins to move into the corneous endosperm
after 3 h.
Mature grains of some cultivars crack or
break apart when exposed to rain after a dry
period. Breaks in the grain surface increased the
rate and altered the pattern of water uptake.
Cultivars with more breakage or with a more
rapid rate of water uptake (intact grains) exhibited
less resistance to weathering. Composition
of leachate from these cultivars was richer in
nutrients. A thicker mesocarp and a softer endosperm
texture usually corresponded to increased
water absorption and richer leachate.
Panicle shape, glume character, wet-season
avoidance, seed size, and other factors contribute
to increased resistance to grain molding
(Glueck and Rooney 1980). A panicle that is
more open than compact does not provide as
much shelter to insects and disease pathogens.
Drooping panicles shelter the grain (instead of
catching water) and decrease the exposure of the
H2O movement
Figure 13. Water uptake and movement in a
sorghum seed. Arrows indicate primary water-entry
areas and subsequent movement in
the seed. Source: Glueck and Rooney (1980).
grain to moisture required for fungal growth.
Longer glumes are considered protective to the
grain, but only if the glumes do not trap water.
Grain maturing during the nonrainy season
avoids the environmental conditions required
for maximum fungal growth. Grain size does
not seem to be a factor, except very large grains
tend to have a softer endosperm texture and are
more susceptible to grain molding.
References
Corneous
endosperm
Floury
endosperm
Stylar
area
Germ Pericarp
Hylar area
Bandyopadhyay, R., Mughogho, L.K., and
Prasada Rao, K.E. 1988. Sources of resistance to
sorghum grain molds. Plant Disease 72:504-508.
Castor, L.L., and Frederiksen, R.A. 1980. Fusarium
and Curvularia grain molds in Texas.
Pages 93-102 in Sorghum diseases: a world re-
View: proceedings of the International Workshop
on Sorghum Diseases, 11-15 Dec 1978,
ICRISAT, Hyderabad, India. Patancheru, Andhra
Pradesh 502 324, India: International Crops
Research Institute for the Semi-Arid Tropics.
Doherty, C.A., Waniska, R.D., Rooney, L.W.,
Earp, C.F., and Poe, J.H. 1987. Free phenolic
compounds and tannins in sorghum caryopsis