Sorghum Diseases in India

4. Using male sterile and fertile cultivars, determine
the precise period of susceptibility of
fertilized gynoecia of pathogens from Africa,
India, and Thailand in several environments.
5. Survey farmers' practices, particularly with
respect to knowledge of ergot contamination
(sclerotia and/or sexual conidia) of seed and
to postharvest land management.
6. Standardize resistance-screening techniques
and evaluation of resistant genotypes, notably
including Ethiopian sorghum. Resistance
in this genotype was claimed in the 1978
Workshop at Hyderabad.
7. Determine role of sclerotia in epidemiology of
ergot disease.
8. Assess losses to ergot in sorghum.
Pearl Millet Ergot
1. Determine the importance, to farmers, of
pearl millet ergot with respect to grain yield
losses and to toxicity of the sclerotia to humans,
livestock, and poultry.
2. Fully test (as alternatives to resource-consuming
ergot-resistant breeding programs for
pearl millet) other possibilities, including use
of existing ergot-resistant populations as finished
varieties, pollen management (pollendonor
variety intersown with a conventional
hybrid) at the farmers' level, and hybrids not
based on sterile cytoplasm (e.g., topcross
hybrids).
3. Study (where resources are available) the biology/epidemiology
of pearl millet ergot and
resistance mechanisms, including postpollination
stigmatic constriction or similar
aging phenomena.
4. Investigate doubled haploids as a means of
fixing short protogeny (ergot resistance) in
pearl millet lines.
5. Encourage institutions funded for basic research
to study the mechanism of postpollination
stigmatic constriction, which
excludes pathogenic parasitization of the
ovary via the stigma.
Bacterial Diseases
1, Document incidence and importance of bacterial
diseases by publishing in appropriate
journals, newsletters, and data bases.
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2. Determine, where possible, sources of resistance
from hybrids, cultivars, or landraces.
3. Determine effect of plant-pathogenic bacteria
on stalk rot.
4. Develop techniques such as semiselective
media or serological procedures for accurate
identification of bacterial causal agents.
5. Determine role of seed transmission in dissemination
of bacterial diseases.
6. Identify portals of entry of plant pathogenic
bacteria into plants through study of hydathodes,
stomates, and other plant structures.
Study effects of wounds.
7. Publish and distribute illustrated handbooks
on bacterial diseases to national scientists
working with sorghum and pearl millet in the
field.
Virus Diseases
1. Continue survey and identification programs
for sorghum viruses and virus diseases.
2. Study crop losses to virus diseases.
3. Study epidemiology host/vector/virus interactions.
4. Standardize inoculation techniques and virus-severity
rating scales.
5. Develop short- and long-term strategies for
managing sorghum virus diseases.
6. Study genetics of resistance: its mechanisms
and the role of inheritance.
7. Develop an index of 'resistance' as a criterion
for selection.
8. Standardize and publish techniques for
research workers in sorghum and millet
virology:
a. ELISA
b. electron microscopy
c. inoculation
d. rating scales
e. screening
9. Collaboration and training
a. Provide training opportunities for plant
virologists in developing nations.
b. International cooperation in serology and
electron microscopy for identification of
sorghum and millet virus diseases.
c. Expand training in molecular aspects of virus
identification.
d. Organize and conduct an international
workshop on sorghum and millet viruses
and virus diseases.