Serving Whitman County since 1877
Serving Whitman County since 1877
COLFAX – “Rain makes corn, corn makes whiskey,” the song goes. But local researchers are finding it is the sun that is the Pacific Northwest’s most reliable and untapped asset in increasing wheat yields.
It has long been assumed it is the amount of water that dictates the yield on wheat, but the amount of water in a given year is one of the most unreliable factors.
Not so with sunshine, and utilizing that sunshine is showing to improve yields by 10 percent according to research by The McGregor Company.
“We have huge environmental potential, yet our region has one of the biggest gaps between current and achievable yield,” said Director of Research for The McGregor Company Cat Salois.
“We have a pretty consistent day length,” she said, noting the Palouse’s regularly sunny days and predictable day length.
According to research through the Maximum Wheat Yield Project, the PNW has a similar head per acre metric as the UK, but consistently lags behind in grains per head and weight per grain. While each yield component is significant, extending grain fill is key to more and heavier grains.
Research indicates that the health and viability of the flag leaf is the key to extending the grain fill period and increasing weight per grain.
“The ‘stay green’, or longevity, of the flag leaf contributes more to yield than any other photosynthetic trait associated with wheat by prolonging the length of time contributed to grain filling,” said Salois. “On average, four bushels per day are lost for each day grain fill is cut short.”
Salois has found that applying fungicide to wheat later in the season extends that grain fill period, even if the plant has no fungus issues.
Wheat goes through a vegetative stage and a reproductive stage. Most factors to improve yield have traditionally been focused on the vegetative stage or before: seed genetics, planting, early fertility. Salois noted all those affect the number of heads per acre, but not the number of grains per head or weight of those grains.
The flag leaf is the last leaf to emerge on a wheat plant. The photosynthesis happening there determines the number of grains and weight. The longer the flag leaf can fill the grains before ripening, the better yield at the end of the season.
During her research, Salois discovered that non-fungicidal health effects of fungicide extend the time the flag leaf photosynthesis can fill the grains. The fungicide – usually seen as a defense tool – has benefits that have nothing to do with treating fungus.
“Applying a true plant health type fungicide will cause a plant to think it has a low-energy status, which then leads the plant to begin taking up more carbon and nitrogen thus increasing photosynthesis beyond what would have occurred without those applications,” said Salois. “Plant health fungicides have also been shown to down regulate ethylene gas production, which is the hormone that signals the plant to ripen and mature. This allows the plant to grow through stresses longer into the season.”
The realization has been eye-opening for a region that assumed water was the limiting factor in yield, but now Salois is realizing it often is not.
“It’s changed how we address and deal with flag leaf,” she said.
Jana Mathia is a reporter at the Whitman County Gazette.
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