ICARDA annual report 2004

ICARDA Annual Report 2004
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with PSbMV and luteoviruses) and
in four faba bean fields in Jabal
Sabir (100% infected with BYMV).
In cereal fields, Barley yellow
dwarf virus (BYDV) was most common,
followed by Barley stripe mosaic
virus (BSMV). Two cereal fields
had a viral disease incidence of
21% or higher; 29% of the samples
taken from one barley field in the
El-Bon Valley were infected with
BSMV and BYDV.
Barley yellow striate mosaic virus
(BYSMV) was only found in one
bread wheat sample. However, this
is the first report of BYSMV in cereals
in Yemen. Bean leaf roll virus
(BLRV) and Beet western yellow virus
(BWYV) were also only found occasionally,
although this is the first
time BWYV has been found in
legumes in Yemen.
Survey of faba bean and
pea diseases and viruses
in China
Yunnan Province
During 2004, Australian, Chinese,
and ICARDA researchers surveyed
the viruses affecting legume crops
in China’s Yunnan province. This
was part of the ACIAR-funded
project of ICARDA on ‘Increased
Productivity of Cool Season Pulses
in Rainfed Agricultural Systems of
China and Australia.’ In all, 4494
plants were collected randomly
(3551 faba bean and 943 pea). A
further 896 plants with virus-like
symptoms were collected (790 faba
bean and 106 pea). All were tested
for 14 different legume viruses
using tissue-blot immunoassay
(TBIA). Testing began on site by
blotting the samples collected each
day, and was completed at the
Yunnan Academy of Agricultural
Sciences, Kunming.
BYMV was found to be an
important disease of faba bean, as
10 fields had a virus incidence of
more than 10%. Six of these had a
virus incidence greater than 75%,
while one had an infection rate of
almost 100%. Incidences of BWYV
and FBNYV were low in almost all
cases. The two exceptions were a
field near Xiao Xinjian with an
FBNYV incidence of 8% and a
BYMV infection rate of 77%, and a
commercial pea field with a high
incidence of BWYV (41%) and a
very low (1%) incidence of PSbMV.
Detailed analysis using a series
of monoclonal antibodies revealed
that the Yunnan strains of FBNYV
are diverse, resembling Milk vetch
dwarf virus in some locations—a
closely related virus that has so far
only been reported in Japan.
FBNYV, BWYV, and Cucumber
mosaic virus were all detected for
the first time in legume crops in
China.
One reason for the survey was
the very high levels of resistance to
BLRV found in Yunnan germplasm
collected in 1996. The 2004 survey
provided further evidence of resistance,
as no BLRV-infected faba
bean was found. There is also
strong evidence that Yunnan pea
has a good level of resistance to
PSbMV, as the survey found few
infected plants.
The project trained local partners
in survey methods, symptom
recognition, and the use of TBIA.
Links were established with
Chinese researchers during the survey,
which will support future
virology research in Yunnan and
other Chinese provinces.
Qinghai Province
In 2004, ICARDA worked with the
Qinghai Academy of Agricultural
and Forestry Sciences (QAAFS), the
Chinese Academy of Agricultural
Sciences (CAAS), and the Australian
Chinese, Australian and ICARDA scientists conducting a survey of faba bean and pea viruses in Yunnan Province. Researchers
spent the day in the field collecting samples (left) and the evening blotting the samples (right).