Breeding wheat varieties for protein? Not so fast

Wednesday, October 18, 2017

Oklahoma State University wheat breeder Brett Carver does not resemble the stereotypical image of a mad scientist at work. However, he and the rest of the OSU Wheat Improvement Team, an interdisciplinary team of researchers, display mad skills when it comes to fulfilling their charge of developing high-performing wheat varieties that thrive in Oklahoma, while more than satisfying the needs of bakers and millers everywhere.

Turns out, variety selection does play a role in the protein content of wheat.

With low levels of protein marking Oklahoma’s wheat crop for the past two years, it is natural to wonder how much attention the Wheat Improvement Team pays to protein content in the development of new varieties.

Well, a lot, actually, though to some degree it is out of the team’s capable hands.

“There’s so much that goes into protein such as the variety, growing conditions and application of nutrients,” Carver said. “We like to think genetics are what control protein content but that’s only part of the equation. There are influences beyond genetics that interact with the genetics to give us that final protein content and final quality.”

Nighttime temperatures during grain development, heat stress, disease and other environmental factors are among those key influences.

Those important factors aside, David Marburger, OSU Cooperative Extension small grains specialist, said one of the common questions he fields from producers revolves around what varieties have higher protein content.

“There are some varieties that, on average, are going to be better when it comes to protein content. But, a lot of times, the variability among varieties at a certain location is outdone by the variability among the different environments where those varieties are being grown,” Marburger said.

To show how protein content for a variety can change from location to location and from year to year, Marburger said grain samples are collected annually from OSU wheat variety trial locations, and the results are published in CR-2135, “Protein Content of Winter Wheat Varieties in Oklahoma.”

This report can be downloaded for free at factsheets.okstate.edu.

Turns out, though, environment and nutrient application, and specifically, nitrogen, usually play a more significant part in the protein content of a crop compared to variety selection.

It also is important to note high – or low – protein content does not necessarily equate to high quality wheat or vice versa.

In very general terms, yes, higher protein content tends to lead to higher quality wheat, but not always. It is entirely possible there are wheat varieties available now that are higher in protein but have tremendously low quality when it comes to bread making, Carver said.

For the OSU Wheat Improvement Team, there is literally a year-round focus on wheat quality. Annually, the team finishes evaluating a crop about the time it is time to harvest another.

“In the breeding program here, and most hard red winter wheat breeding programs, we’re trying to hit a window that in terms of protein content is about 11.5 percent up to 13 to 13.5 percent. I’d like to hit the upper fringes of that, if possible,” Carver said. “But you still have to have certain kinds of proteins present to achieve certain kinds of quality in bread.”

Hitting that preferred window for protein content in a wheat is possible, Marburger said.

“It’s important for producers to remember they can achieve the target of 11.5 percent protein in their crop with a high degree success with pretty much any variety, plus likely increase yield along the way, if they properly manage their nitrogen fertilizer.”