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.
