Canada
June 15, 2009
The effects of fusarium head
blight in wheat and barley have been well documented over the
past two decades. Mycotoxins produced by the fungi responsible
can make pigs sick and cause beer to foam out of control. But
much less research has been done to evaluate the effects of
fusarium fungi on oats.
"Fusarium tends to be more of a problem in the eastern prairies
and becomes less of a problem as you move further west," says
Andy Tekauz, a plant pathologist with Agriculture and Agri-Food
Canada, at the Cereal Research Centre in Winnipeg.
"We can find fusarium head blight in most Manitoba oat fields.
Why it's an interesting disease, from a research point of view -
I call it an insidious disease. You don't see it in oats as you
do in barley or wheat, where the disease is quite obvious
in-season. So the likely assumption in the past was that oats
weren't affected by fusarium."
To quantify the effects of fusarium head blight in oats, plus
identify and incorporate genetic sources of resistance, Tekauz
and a group of collaborating researchers received funding from
the Endowment Fund, which is administered by the
Western Grains Research
Foundation (WGRF).
"We wanted to find out if fusarium is a problem and if so, how
big and widespread it was. For the three-year project, we
sampled a number of fields to find out how many fields had
fusarium and which species were involved," says Tekauz.
"We also wanted to look at oats from Canada and other parts of
the world, to see if there was the possibility of improving the
resistance level present in our commercial varieties and
breeding lines."
Tekauz was able to demonstrate that fusarium head blight is
indeed a problem in commercial oat fields, with more than 75
percent of the fields surveyed annually affected. He was able to
isolate fusarium fungi from ten to 15 percent of the seed taken
from those fields.
"In wheat, about 95 percent of the problem is caused by F.
graminearum. In barley, there are a number of other species
involved and these same species are also involved in oats," he
says.
The four species include F. graminearum, F. poae, F.
sporotrichioides and F. avenaceum.
"We find these four every year in oats when we do our surveys,
but their proportion tends to change from year to year. So
environment or other factors play a role in determining what
levels of these fungi will be found on the seed," says Tekauz.
The researchers then tested Canadian oat varieties and breeding
lines, plus material from elsewhere, for genetic resistance.
"Among Canadian oats, there was variability in fusarium head
blight resistance. We were also able to identify genetic
resistance in lines obtained from other countries, particularly
South America," he says.
"The resistance we have identified in the project is currently
being used in oat breeding programs in western Canada, with the
aim of improving performance to fusarium head blight and
reducing the levels of mycotoxins present in oats."
Fusarium rating system
Tekauz says that in general, oats tend to be more resistant to
fusarium head blight than barley or wheat.
"When we put susceptible wheat and barley varieties as checks
into our oat fusarium head blight nurseries, they accumulate
more DON than the bulk of the oat varieties," he says.
"We would slot most oats into the MR to MS category - moderately
resistant to moderately susceptible. In wheat and barley,
there's a whole bunch you put in MS or S."
The researchers are currently working on a ratings system for
ranking fusarium resistance in current and future oat varieties.
"What we're doing now is screening the western oat co-operative
test, to get base-line information on fusarium resistance in our
elite breeding lines. We have identified one of Brian
Rossnagel's lines that was in the coop test in 2006 and 2007
that performed quite well," says Tekauz.
Tekauz says looking for resistance to fusarium head blight based
on low DON accumulation is now a goal and priority in current
Canadian oat breeding programs.
The Endowment Fund, the original core fund of WGRF, has
supported more than 200 research projects since 1983.
For more information on the project check the WGRF Web site
at www.westerngrains.com
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