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With Wheat, Weather Matters

UI Extension works to address falling numbers

A field southeast of Lewiston and 15 other fields across northern and southern Idaho will become temporary weather stations overseen by University of Idaho Extension researchers to track conditions that can damage wheat quality.

Last year, wheat farmers across northern Idaho and in adjacent states watched world wheat prices drop as an abundant crop — including their own — neared harvest. They remained optimistic that the high yields would offset low prices. Then reality hit, the crop’s quality was subpar because of a complicated falling numbers issue.

Suddenly as much as 40 percent of their crop was affected by a test that could divert much of their harvest from the human food market to animal feed at much lower prices. The low falling number scores cost growers millions of dollars with estimates ranging from $30 million to $140 million region wide.

The weather stations will help researchers and wheat growers better understand what environmental factors led to low falling number scores.

Researchers say factors such as big temperature swings, highs in the 70s or 80s and lows in the 30s, early in July 2016 damaged wheat kernels as starch was forming.

In 2014, heavy rains at harvest time across southern Idaho damaged wheat by causing it to sprout, another factor that can lead to low falling number scores.

The Idaho Wheat Commission funded the purchase of 16 weather stations that will monitor temperature and rainfall at wheat variety trials throughout the state.

The plan by UI Extension Nez Perce County-based regional educator Doug Finkelnburg will help track both the environmental and genetic factors that contribute to low falling number scores.

Moscow-based regional agronomist and pathologist Kurt Schroeder oversaw weather station installations at variety trial locations. The weather data will help sort through why some varieties seem resistant and others vulnerable to the problem.

In southern Idaho, Aberdeen-based small grains pathologist Juliet Marshall, who holds the Wheat Commission-endowed “Potlatch” Joe Anderson Cereal Agronomics Professorship, will collaborate on the weather monitoring.

During normal growing seasons, growers in relatively small locations encounter low falling number scores. The heavy 2014 and 2016 losses broke from that pattern.

Increasing problems with falling number scores led UI Extension researchers to launch multiple studies, many funded by the Idaho Wheat Commission, to better understand the situation.

UI wheat breeder Jianli Chen, who holds the Idaho Wheat Commission-endowed D. Blaine Jacobson Wheat Breeding Professorship, will focus a study on finding the causes and effects of low falling number scores in hard white spring wheat grown in 2015 and 2016.

The falling numbers test measures the amount of time it takes a stirring rod to drop through a cylinder of gelatin-like wheat starch. A thin starch gel means a low falling number score. Many wheat millers make 250 the minimum number they will accept for making flour, and prefer wheat with scores of 300 and up.

Food scientist Amy Lin is studying the wheat enzymes known as alpha-amylases and their effects on falling number scores. Lin will study the effects of pre-harvest sprouting on wheat starch and flour quality.

UI wheat geneticist Daolin Fu will study the enzymes that affect wheat quality and their genetic basis.

Story by Bill Loftus, College of Agricultural and Life Sciences

Douglas Finkelnburg

Area Extension Educator, Cropping Systems

Kurtis Schroeder

Cropping Systems Agronomist, Associate Professor

Ag Science, Room 318


University of Idaho Extension

Physical Address:
E. J. Iddings Agricultural Science Laboratory, Room 52
606 S Rayburn St.
Moscow, ID

Mailing Address:
University of Idaho Extension
875 Perimeter Drive MS 2338
Moscow, ID 83844-2338

Phone: 208-885-5883

Fax: 208-885-6654


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Barbara Petty