Outlook ‘cautiously optimistic’ for low falling number in wheat

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CAPITAL PRESS – MATHEW WEAVER – USDA research plant molecular geneticist Camille Steber says she is cautiously optimistic about the prospects of falling number in this year’s Pacific Northwest wheat crop. Steber is testing wheat samples for susceptibility to the starch damage problem.

Winter wheat from Washington State University’s Spillman Farm underwent testing for the enzyme late-maturity alpha amylase this summer.

“I am cautiously optimistic,” she said.

Falling number is a test that measures wheat quality. Low falling number is caused when the enzyme alpha amylase breaks down starch in the grain. Overseas customers have strict requirements for falling number tests. Farmers receive lower prices for their grain if tests show a falling number below 300.

Steber, research plant molecular geneticist in Pullman, Wash., is testing wheat from Washington State University’s Spillman Farm in Pullman, Wash. for late-maturity alpha amylase, or LMA — a cause of starch damage.

“The only thing consistent about LMA is that it’s consistently inconsistent,” Steber said.

In 2016, low falling number test results hit a large portion of the Pacific Northwest’s wheat crop, costing growers between $30 million and $130 million in discounts.

LMA, an enzyme, is the result of extreme temperature fluctuations during grain filling. It is one of two causes for sprout damage to occur in wheat, and show up in falling number tests at grain elevators. The other is pre-harvest sprouting caused by rain.

“This LMA thing kind of snuck up on us,” Steber said. “We weren’t looking for it until farmers started to come to me and saying, ‘Hey, I had no rain … Tell me why I had low falling number.’”

Wheat development this year slowed due to cold temperatures after pollen shedding, Steber said. She hopes things slowed enough to avoid the severity the industry saw in 2016.

“Temperature fluctuations weren’t as big,” she said. “In 2016, one day we were in the 90s, the next day we were in the 70s and the following day we had a high in the 50s. We just had a ridiculous temperature crash that year.”

This year, temperatures hovered from the 60s to the 80s and never quite hit the 90s, Steber said.

Spring wheat is currently in the period of susceptibility, but forecasts indicate temperatures will remain consistently high, Steber said.

Variety trials have begun harvesting in the center of the state. She expects to receive samples she can run through the falling number testing process.

Steber puts the wheat in an incubator to “cold-shock” it.

“The only thing I can do at this point is give breeders information about which breeding lines are susceptible, so they can make good choices in their breeding programs, so farmers will stop having quite so much difficulty,” Steber said.

Steber recommends farmers access information from 2016 on her website to determine which varieties are susceptible to low falling number.

Posted by: Matthew Weaver, Capital Press, Published on July 17, 2018 9:28AM

Picture: Camille Steber – USDA – Winter wheat from Washington State University’s Spillman Farm underwent testing for the enzyme late-maturity alpha amylase this summer.