Sorghum Diseases in India

8. Use of field and controlled environment
screening and other research techniques to
obtain information on:
a. host/pathogen interaction,
b. germplasm response to foliar pathogens,
and
c. pathogen variability
9. Research to understand the biological mechanism
influencing survival and function of
pathogen propagules.
10. Determination of influences of naturally occurring
and introduced epiphytic and other
leaf microflora on host, pathogen, and host/
pathogen interactions be studied.
Anthracnose
1. Investigate host/parasite/environment interactions.
2. Evaluate known sources of resistance worldwide
and screen nontested world collection
items at known 'hot spots.'
3. Monitor pathogen variability, using standard
differential varieties and regionally important
cultivars
4. Determine relationships of grain and foliar
anthracnose to stalk rot.
5. Determine mechanisms of anthracnose
resistance.
6. Evaluate chemicals (e.g., fungicides, plantgrowth
regulators, etc.), cultural practices,
and biological controls with the aim of developing
crop-management strategies for
control.
7. Develop more effective and relevant screening
techniques for identifying resistant
materials.
8. Determine role of seedborne inoculum.
9. Identify and utilize improved and exotic
sources of resistance by classical or innovative
(biotechnological, genetic engineering,
etc.) methods.
10. Determine the inheritance and heritability of
resistance.
11. Elucidate the etiology and epidemiology of
the disease.
12. Evaluate collected isolates from graminaceous
hosts at containment facilities or in
a temperate climate with less sorghum hectarage
to determine the variability of the
pathogen and host range.
13. Investigate taxonomy of Colletotrichum graminicola
on different graminaceous hosts.
14. Establish an 'Anthracnose on the Gramineae'
working group as part of the International
Society of Plant Pathologists to
promote cooperation in research activity
with anthracnose on graminaceous hosts.
Sorghum Stalk Rot
Because of the need for reliable methodology to
screen genotypes resistant to stalk rot and a multilocational
cooperative program for the identification
of sources of resistance to this major
sorghum disease, the Committee recommends:
1. Methodology for stalk-rot screening:
a. Use of nonsenescence and resistance to
lodging as indicators of stalk rot resistance.
b. Use uniform criteria to evaluate genotypes.
Use a 1-to-5 scale for both parameters,
with a plant free of observable
symptoms receiving a rating of 1, and a
severely diseased or dead plant receiving a
rating of 5. The lodging scale should be
based on percentage of lodged plants.
c. Make stalk rot reaction comparisons only
within entries of similar maturities.
d. Take readings any time between physiological
maturity and harvest if differential
reactions permit comparisons among
genotypes.
e. Record flowering date and plant height for
each entry.
f. Because of the relationship between susceptibility
to stalk rot and high yield, we
recommend that yield or a yield rating be
recorded, particularly in resistant entries.
This may reveal genotypes that combine
high yield and stalk rot resistance.
g. In a stalk rot-resistance evaluation sowings,
we recommend entries be seeded in
4-m rows. In advanced lines, use replications
and multiple sowing dates and locations
as extensively as appropriate. We
also recommend including local susceptible
cultivars, sown strategically through
the screening nursery. For early generation
evaluations where replications are not necessary,
we suggest sowing at least one susceptible
control for each five entries.
2. Multinational Cooperative Program
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