Sorghum Diseases in India

using differing inoculum concentrations in order
to detect differences among genotypes?
Frederiksen: Seems like a very useful approach
to me. You may learn much about levels of resistance
and infection thresholds.
Laing: Many USA postgraduate programs have
an extensive involvement with high technology:
genetic engineering, crop-loss assessments,
ELISA. Does the INTSORMIL program take into
account that many researchers from developing
countries will not have access to such technologies?
How is the training of scientists from the
developing world tailored to be appropriate
to the available technologies of their home
countries?
Rosenow/Frederiksen: That is a good question;
while extremely important, we are not in a position
to discuss these issues at this forum. The
issue is addressed by each INTSORMIL graduate
advisor based on the needs and resources of
each collaborator and each graduate student.
Andrews: Do breeders include Striga resistance
in their breeding program?
de Milliano: Not necessarily. However, certain
agronomically acceptable sorghums with resistance
have been released, and I believe they will
be used both in production fields and in breeding
programs.
Andrews: It is desirable to use pathology concepts
and practices in dealing with Striga. For
instance in an area where a particular disease
was prevalent, all material would be tested for
undue susceptibility to that disease prior to release
(if there had been no breeding programs
specifically for that disease). This principle is not
the same as breeding for resistance. Even with
unreliable Striga incidence, the highly susceptible
are often obvious and do not escape.
Gupta: There are no reliable techniques for
screening pearl millet for resistance to Striga.
Striga epidemics in western Africa are sporadic,
consequently we often have failures and occasionally
the levels of Striga do not permit us to
differentiate among host reaction classes.
King: One of the reasons that cultivars are re­
leased without Striga resistance is that there are
no reliable screening techniques. Also, I believe
that Striga control depends on more than deployment
of resistance genes. Cultural practices
are involved as well.
House: At ICRISAT Center, cultivars and hybrids
have been developed without an effort to
incorporate Striga resistance. However, a separate
program designed to select for resistance
was successful. Improvement in yield was selected
in resistant material. Resistant lines
are used by farmers in endemic areas. Outside
endemic areas, these lines would not be
competitive.
Homans: We must use caution and not be concerned
with only one disease or groups of diseses.
We must also be concerned with insects,
birds, nematodes, rodents, and even human pilfering.
Our challenge is to guide our world with
infinite wisdom so that our goal of producing
more food for the expanding populations that of
the world may be achieved. A holistic approach
must be used in all of our research.
Obilana: Now that pathologists have been encouraged
to do more research on Striga in collaboration
with the breeders and agronomists, we
need to complete the inheritance patterns in
Striga. I will help to provide some of the
information.
We should also add the conversion program
being done at ICRISAT on the guineaense and
roxburghii sorghums from Nigeria which, when
successful, will make available good sources of
hard-grain traits and mold resistance to the sorghum
researchers of the world.
House: Over the past 25 years there has been a
substantial improvement in sorghum. The collection
and conversion programs have each been
valuable. It would be useful for this body to include
a recommendation supporting the collection
and evaluation and the conversion programs
alike.
Anahosur: We have tested several germplasm
lines of sorghum and have found disease resistant
genotypes, but they are often quite susceptible
to insect pests. Therefore it is necessary to
consider both in the crop-improvement process.
What should be the strategy for this?
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