Sorghum Diseases in India

Guiragossian: Is there a price difference between
white and red seed sorghums?
House: In the 1985-86 season, the price of redand
white-grained sorghum was U.S. $180 t -1 ,
equal to that of maize. Because of the surplus the
price of red-grained sorghum was dropped to
U.S. $100 t -1 , while the price of white-grained
sorghum and maize remained at U.S. $180 t -1 .
These are purchase prices by the Grain Marketing
Board; the selling price is U.S. $220 t -1 for
red- and white-grained sorghum and for maize.
Balasubramanian: Is the bacterial pathogen
(Pseudomonas andropogonis), for which South Africa
has imposed a quarantine, seedborne?
de Milliano: The pathogens of bacterial leaf
streak (Xanthomonas campestris pv holcicola) and
bacterial leaf stripe (Pseudomonas andropogonis)
have both been recorded as being seedborne.
(See also Claflin et al. in this Publication.)
Vidyabhushanam: It was mentioned that seed
rots and seedling blight may reduce stands by
as much as 50%. What measures have been
evolved to overcome this problem?
de Milliano: This information was in relation to
downy mildew sick plot conditions, and does
not necessarily apply to farmers' fields.
Mushonga: The people in Zimbabwe prefer the
white-grained sorghums, if they can purchase
them. The reason why red sorghums are grown
by commercial farmers is that they need them
for brewing opaque beer.
Qhobela: What specific virus diseases are prevalent
in the region?
de Milliano: I do not know We believe that we
have a strain of maize dwarf mosaic virus.
Vidyabhushanam: Dr Hulluka, your generalized
statement that diseases are more serious on
high-yielding cultivars than on local landraces
needs substantiation with specific examples!
Discussion
Hulluka: We have experienced this situation in
many instances. Improved lines are more prone
to attack by anthracnose, leaf blight, and ergot in
Ethiopia, specially when they are used in largescale
farming.
House: Not all landraces have resistance and
not all introductions are susceptible. While it is
true that some introductions have greater susceptibility,
it is also true that some of the most
useful sources of resistance are from introductions.
Guiragossian: Smuts (covered and loose) seem
to be a problem in eastern Africa. We all know
there are chemicals that can be used to overcome
smuts, yet farmers do not use them. Therefore, I
recommend that we identify genotypes with genetic
resistance as an alternative method for
kernel smut control.
Hulluka: I have no information regarding
breeding for smut resistance. Since these diseases
can be effectively controlled by seeddressing
chemicals, screening for resistance to
these diseases may not be justified.
King: Covered smut and loose smut are very
effectively and economically controlled by seed
treatment. I would hope that this discussion
would not favor breeding for resistance to these
diseases; breeding for resistance is a far greater
undertaking for a resource-poor country than
extending purchase of seed-treatment fungicides
to farmers.
Esele: Covered and loose smut are the most important
smuts in the eastern African region.
Since sorghum is a subsistence-level crop, seed
treatment is not economical. Utilization of host
resistance is the best control, because farmers
keep their own seed for sowing.
Teri: (With regard to Dr King's comment) On
the usefulness of seed treatment This is alright
where farmers buy seed. What about situations
where farmers grow their own seeds? There we
may need to encourage farmers to buy seeds or
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