Top Crop Manager

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Rating system helps long and short-term future for wheat

Boost to soft white wheat production and breeding programs.

November 14, 2007
By Top Crop Manager


36aCall it one more tool for the toolbox. A rating system to measure the susceptibility
of wheat varieties to fusarium head blight (FHB) made its debut in 2005 as part
of the field performance trials. Dr. Duane Falk, a cereal breeder with the University
of Guelph, created the index using visual symptoms of fusarium head blight,
also known as scab, combined with relative values of DON (deoxynivalenol) toxins
in the grain, a first for such a measured ranking.

"It's one of the first times we've been able to combine both of those
because they both have an impact," explains Falk. "Fusarium head blight
has an impact on the yield, so that affects the producers, and the DON impacts
on the flour, milling and baking industries, so we've been able to put the two
together to see which varieties represent the best package, and it seems to
be working, it's fairly logical."

The index ranks all wheats from the performance trials, but the industry is
particularly interested in a revival of soft white wheat. There is an acknowledgement
within both the seed and milling sectors that there always will be a market
for quality soft white wheats for the pastry, cookie and cracker trades. In
June 2006, the price for soft white wheats carried its own built-in premium,
a reflection of the over-supply status for soft reds. Some industry sources
insist that for growers capable of a timely application of Folicur and who can
harvest early to reduce the risk of sprouting, there is a viable market for
soft white wheats.


The challenge here, notes Falk, is the index showed considerable variation
with the soft white varieties. "They're not as good as they should be,
but there is variation (in their susceptibility) and some of them can be protected
to some extent using something like Folicur, particularly in a year like 2006,"
he says. It is possible to make the grade, "but it would require a premium
to make it worth while."

How the rating works
The index is based on scores accumulated from inoculated trials, meaning the
varieties are under considerable pressure and ensuring that all varieties are
infected uniformly. Each variety is scored at three different locations every
year according to susceptibility to fusarium and any corresponding toxicity
from elevated DON levels. The data is gathered for a minimum of two years before
it is calculated for the index. The higher the number, the greater the susceptibility.
"But we've broken it down into a four-step scale so farmers don't have
to interpret everything," explains Falk. "The best ones are moderately
tolerant, the next are moderately susceptible, then susceptible and then highly

As it stands now, the differences in susceptibility and tolerance levels appear
to be primarily genetic. From a company perspective, the good news is the spread
between good and poor is fairly even; each company has good varieties and some
poorer performers.

That, according to Crosby Devitt, will hurt those susceptible varieties in
the short-term, but in the long-term, it will help push the seed companies to
improve their lines. "In reality, it's going to be hard on the ones that
are very susceptible because producers are just going to stop growing them if
there is another choice that's good agronomically," reasons Devitt, the
manager of research and innovation for the Ontario Wheat Producers' Marketing
Board. "But it's going to push the variety developers to put more focus
on it, because that's going to generate better sales." -30-