Sorghum Diseases in India

these are very similar to wounds caused by
insects.
Balasubramanian: The green islands you have
shown in your photograph, of maize dwarf mosaic,
are they similar to the green island effects
as a result of rust infection in sorghum?
Toler: The cells that are green in the mottled area
do not contain virus particles. This is a cellular
phenomenon not associated with host-plant
resistance.
de Milliano: Do you know of symptomless carriers
of maize dwarf mosaic virus?
Toler: No.
Njuguna: In terms of symptoms, is there difference
in the expression of virus, rather than viroids,
in plant tissue?
Toler: No! The symptoms are not necessarily different;
the difference is the absence of a protein
coat for a viroid.
Teyssandier: I would like to know if there is a
vector involved in transmission of yellow-banding
virus.
Toler: The vector at present is unknown.
Teyssandier: I would like to know if it is possible
to establish the relative importance of a sorghum-virus
disease using a comparison of
incidence and distinction on yield loss.
Toler: Yes, losses and distribution can be used to
evaluate virus diseases.
Vidyabhushanam: What is the role of seed
transmission with specific reference to MDMV
in sorghum?
Toler: Maize dwarf mosaic virus is not seedborne
in sorghum, but is seedborne in maize.
Vidyabhushanam: Can you indicate the resistant
genotypes of sorghum to MDM?
Toler: Tx 090, BTx 623, QL 3 India Sel., BTx 51.
Homan: Insects have a tendency to feed down
the row, so your half-row techniqe for inoculation
could develop a delayed transmission of the
virus in the nontreated part of the row.
Toler: True, but with the half-row method,
where half of the row is the control, an infected
control plant shows that natural infection is taking
pake.
Giorda: Have you considered the possibility of a
mixed infection of SCMV-fg and Acremonium
spp? Isolation from the plant infected with the
virus is necessary to detect the presence of the
fungus.
Garud: The repeated isolations from roots of
such plant yielded no Acremonium and thus
Acremonium infection is overruled. (Editor's
note: Acremonium strictum can produce foliar
systems and wilting even though not infecting
roots.) The transmission with R. maydis and L.
saccharin yielded virus transmission.
Guiragossian: Has work been done on the genetic
inheritance of resistance to MDMV?
Giorda: Yes! Teakle et al, in Australia; Giorda et
al. in Texas.
Wall: Is there a characteristic difference between
the red stripe reaction you showed us and acremonium
wilt symptoms (for field identification)?
Garud: Yes! In red stripe, mosaic will later develop
characteristic interveinal symptoms not
associated with acremonium wilt.
Mughogho: I visited field experiments of Dr
Garud in January 1985 and did not see symptoms
of Acremonium wilt in the trials at that
time.
Laing (to Garud): Is the sorghum resistance you
spoke of in relation to sugarcane mosaic virus
alone, or to aphid resistance as well? Or to the
mosaic virus and other things?
Garud: It is to virus only.
Cole: How does soil type affect the incidence of
seedling diseases?
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