Sorghum Diseases in India

cattle, but other studies suggest that feed contaminated
with toxins produced by Fusarium
spp are deleterious to poultry and swine.
Thomas: Could you clarify the distinction between
grain mold and weathering?
Forbes: First let me say that this distinction is
not made by all grain mold scientists. Grain
mold occurs before physiological maturity and
involves very few fungi acting as parasites.
Weathering occurs after physiological maturity
and includes many field fungi acting in conjunction
with climatic factors.
Adipala: In terms of yield loss, how do you compare
loss due to grain mold with weathering?
Does it appear that the genes for resistance to
grain mold are the same as those that work
against weathering?
Forbes: First you have to establish two relationships.
One is the relationship between grain mold
severity and loss and the other is the relationship
between weathering severity and loss. To do this
you have to isolate the effects of grain mold from
those of weathering. There are several theoretical
ways of doing this, but it is difficult to do in the
filed. Once these relationships are established you
can try to estimate yield loss posed on grain mold
and weathering severity. This is very hypothetical
and I would guess that for crop-loss assessment
both weathering and grain mold would be considered
together. In regard to your second question,
it appears that grain-mold resistance is
generally related to weathering resistance. In
some cultivars, however, the two types of resistance
seem to be independent.
Rosenow: Regarding the data presented on flavan-4-ols
analysis, were white resistant cultivars
evaluated or are all white sorghums very low in
these compounds? If all are low, this analytical
procedure would not be useful among white
types.
Waniska: Both GM-susceptible and GM-resistant
cultivars evaluated to date have low levels
of flavan-4-ols. This compound is high in grainmold
resistant red pericarp cultivars. Resistant
cultivars with a pigmented testa can have either
high flavan-4-ol levels, high tannin levels, or
both.
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Guiragossian: In my experience, there are no
yellow-endosperm sorghums resistant to grain
mold in Mexico. All yellow endosperms tested
for grain mold have been, without exception,
susceptible.
Mukuru: This may be true. However we need to
screen for mold resistance in yellow endosperm
types with hard and vitreous grains.
Mushonga: Did you try to cross the brown-grain
type with a yellow-endosperm type to see if
there was resistance in the progeny?
Mukuru: No, we did not.
Vidyabhushanam: Have the hard-grain types
reported to have mold resistance been evaluated
for food quality?
Mukuru: There are reports which indicate that
vitreous grains have low digestibility. We need
to evaluate the digestibility and food quality of
mold-resistant sorghums. Vitreous grains are
preferred for regate in eastern Africa.
Mbaye: Are there differences in resistance to
grain mold from different types of sorghum, i.e.,
between guineaense and caudatum types?
Mukuru: Resistance to grain mold has been
identified in various types. Resistance to grain
mold for colored grain types without the testa
layer has been identified in guineaense types.
Obilana: In terms of utilization of germplasm
and disease resistance, how much have you implicated
the different sorghum races like the
guineas (hard grain) and farafara - caudatum
(medium/soft grain) which are both white (and
some red without pericarp in the guineaense). in
mold resistance?
Mukuru: The mold-resistant sources identified
are diverse in geographic origin, as well as taxonomic
races. The colored-grain mold-resistant
sources without the testa layer, however, are
predominantly the guineaense, or kafir, types.
Obilana: Following Dr Mukuru's answer to my
first question, I recommended that these longseason
tall and photosensitive sorghums (guineaense
and caudatum farafara) be evaluated for