Sorghum Diseases in India

Using the World Germplasm Collection in Breeding
for Disease Resistance at ICRISAT
S.Z. Mukuru 1
Abstract
Disease-control strategies at ICRISAT emphasize the development of breeding materials resistant
to the important cereals diseases, This effort is interdisciplinary, with breeders and pathologists
cooperating. The process involves developing efficient, reliable field and laboratory screening
tecniques; identifying sources of stable and durable resistance in the sorghum germplasm collection
and other breeding materials; testing stability of resistance with various races of the pathogens in
multiple environments; and then incorporating the stable resistance into high-yielding
agronomically desirable genotypes.
Introduction
A wide range of abiotic and biotic stress factors
limit sorghum production in the semi-arid
tropics (SAT). Of these, the most important and
widespread are drought, insect pests, and diseases.
For resource-poor farmers in the semiarid
tropics the most practical control method is
growing resistant cultivars, if available. This is a
simple and an effective means of improving stability
of yield.
In India, the most important diseases of sorghum
are grain molds, stalk rots, downy mildew,
and several leaf diseases (see Anahosur,
this publication). Disease-control strategies at
ICRISAT emphasize the development of breeding
material resistant to these diseases. At ICRI-
SAT this effort is interdisciplinary and involves
breeders and pathologists. The procedure follows:
1. Develop efficient, fast, and reliable field and
laboratory screening techniques.
2. Use these techniques to identify sources of
stable and durable resistance in the sorghum
germplasm collection and breeding material.
3. Test stability of resistance in different environments
and with races of the pathogens.
4. Incorporate identified stable resistance into
high-yielding agronomically desirable genotypes.
At ICRISAT Center we have a genetically
diverse collection, numbering in the hundreds,
of germplasm of indigenous cultivars and
weedy and wild relatives of sorghum. We have
developed effective techniques to screen the entire
collection to identify those resistant to various
diseases.
Resistance Screening Techniques and
Sources of Resistance
The key to the identification of sources of stable
resistance is the development of reliable, efficient,
and epidemiologically sound screening
techniques which discriminate between resistant
and susceptible genotypes (Mughogho 1981).
ICRISAT screening techniques have been effective
for grain molds, downy mildew, stalk rots,
rusts, and anthracnose (ICRISAT 1984).
1. Principal Plant Breeder, Cereals Program, ICRISAT Center, Patancheru, Andhra Pradesh 502 324,India.
Mukuru, S.Z. 1992. Using the world germplasm collection in breeding for disease resistance at ICRISAT. Pages 325-328 in
Sorghum and millets diseases: a second world review. (de Milliano, W.A.J., Frederiksen, R.A., and Bengston, G;D., eds). Patancheru,
A.P. 502 324, India: International Crops Research Institute for the Semi-Arid Tropics. (CP 736).
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