Sorghum Diseases in India

for accurate evaluation of resistance levels and
of differing pathotypes or races are required.
The biotype/race situation now experienced
with pathogens of downy mildew, anthracnose,
and many other diseases create many problems
with identification. Knowledge of sources and/
or types of resistance with the highest probability
of remaining stable is immensely important,
but very difficult to obtain.
Breeding Procedures
The third major component of effective use of
the World Germplasm Collection is the actual
incorporation of resistance into improved lines
and/or hybrids that are agronomically elite and
possess the other traits necessary for the adoption
and use by producers.
To breeders, disease and resistance to disease
are simply additional traits with which a breeder
must struggle. In most cases, more than 20 genetically
controlled important traits will be involved,
and the number can be as high as 50.
Disease resistance should be a basic component
of a plant breeding program. Success requires
close cooperation between breeders and
pathologists. It must be more than just a breeder
sending his breeding lines to the pathologist for
screening and the pathologist rating the lines
and writing up a report. A common nursery—
planned, established, and managed cooperatively
in every way—is essential.
Knowledge of the inheritance of resistance,
or at least a working knowledge of the ease of
transfer, is essential. Inheritance of resistance to
most important sorghum diseases is summarized
in Table 1. Selection of specific breeding
and screening techniques requires consideration
of the nature of the host-parasite interaction and
apparent vulnerability to each disease. These are
summarized by Rosenow and Frederiksen
(1982).
Several papers (Rosenow 1980; Frederiksen
and Rosenow 1980; Rosenow and Clark 1987;
Rosenow and Frederiksen 1982) discuss the diseases,
list sources of resistance, and present discussions
on utilization of exotic germplasm with
sorghum. Frederiksen and Rosenow (1980) detail
inoculation, inoculum preparation procedures,
and screening techniques. Many kinds
of breeding procedures, such as pedigree line
breeding, backcross breeding, and population
Table 1. Summary of inheritance of resistance
of some diseases of sorghum.
Disease Inheritance pattern
Grain mold Intermediate/
dominant
Downy mildew Dominant
Anthracnose Dominant
Charcoal rot Recessive/
intermediate
Maize dwarf mosaic Dominant/
recessive
Head smut Dominant/
intermediate
Fusarium head blight Dominant/
intermediate
Fusarium stalk rot Recessive/
intermediate
Rust Dominant
Gray leaf spot Recessive
Ladder spot Recessive
Leaf blight Dominant
Sooty stripe Recessive/
intermediate
Bacterial stripe Recessive
Bacterial streak Recessive/
intermediate
Acremonium wilt Recessive/
intermediate
Zonate leaf spot Recessive/
intermediate
Long smut
Sugary disease ?
Covered kernel smut Dominant
Loose kernel smut Dominant
breeding have been successfully used to breed
for disease resistance. The most overall desirability
of the line in which resistance is found,
and the type of material, line, hybrid, or popula-
?