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Wheat

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With tweezers, mixers, and genetic maps, OSU researchers are turning wheat into breads, noodles, and pastries.
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OSU food chemist Andrew Ross takes us into his bakery laboratory, where he explores the properties of soft and hard wheats.

Andrew Ross’s lab at Oregon State University smells like a bakery. That’s because it is. The cereal scientist wears checkered chef’s pants and a white chef’s coat. There’s an oven in the corner and an empty 50-pound sack of flour near the emergency shower. Golden loaves of sandwich bread are lined up on a metal rack. Flour dusts almost everything.

Ross sprinkles durum semolina on a proofing board. He pauses. He’s multitasking. Oh yes, pull the loaves of dough from the rack where they’re rising. He’s making a rustic ciabatta. Half of the flour in it is ground from wheat called Norwest 553 that OSU helped develop. In 26 minutes he’ll know if his experiment is a success.

Ross is on a quest to make world-class bread out of Pacific Northwest wheat. He’s just one piece of a team at OSU that’s collaborating to help the wheat industry make dough. And it’s a lot of dough. Oregon’s farmers sold $312 million of wheat last year, making it the state’s fourth-largest agricultural commodity.

Wheat has been a staple of civilization ever since it was domesticated about 10,000 years ago in the Fertile Crescent of the Middle East. No, early Neolithic villagers weren’t out roaming alluvial terraces, lassoing wild wheat, and housetraining it. But through centuries of repeated sowing and harvesting, these pioneering farmers were selecting (albeit sometimes unintentionally) plants with large grains, erect stems, and spikes that didn’t shatter and spill their kernels on the ground. It was a primitive, slow process.

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OSU wheat breeder Jim Peterson discusses genetic innovation and increased food quality.

If only they had had Jim Peterson. The OSU wheat breeder is doing basically the same thing, only faster, smarter, and with much bigger words. He introduces desirable genes into wheat that is lacking them. But introducing a gene into a spike of wheat isn’t a simple handshake. It’s an eye-squinting job involving tweezers and scissors, essentially neutering the male anthers on the wheat flower. To be clear, this is not the same process as genetic engineering, which involves modifying genetic information in cells by adding single genes or fragments of deoxyribonucleic acid (DNA).

anthers in tweezers
A steady hand trims a wheat flower and removes the pollen-forming anther in order to control fertilization among selected varieties. Photo by Lynn Ketchum.
Jim Peterson
Carefully tapping pollen from the flower of one wheat variety to the flower of another, OSU wheat breeder Jim Peterson cross-pollinates selections at OSU’s experimental Hyslop Farm near Corvallis. Photo by Lynn Ketchum.

Peterson, who started working at OSU in 1998, carries on a long tradition of wheat breeding at the university. He has been involved with the development of several varieties that thrive in Oregon, including the high-yielding Tubbs and Tubbs 06; ORSS-1757, which is excellent for cookies and cakes; Goetze, which is suited for the Willamette Valley; and ORCF-101 and ORCF-102, which resist a particular herbicide.

To understand how traditional breeding works, it helps to know a little something about the sex life of wheat. Wheat is, one could say, an incestuous plant. The male anthers pollinate the female stigma in the same flower, rarely straying outside the house, let alone the neighborhood. That is until Peterson and his crew come along. They’re the Match.com for wheat.

Every spring, these matchmakers can be found sitting on stools in a field, hunched over wheat spikes at OSU’s
Hyslop Farm a few miles outside of Corvallis. They carefully snip off the tops of selected flowers, which each contain three tiny anthers and a white, speck-sized ovary. They remove the anthers with tweezers as if plucking an eyebrow. A pro can perform this surgery on 15 or 20 spikes in an hour, Peterson says. A couple of days later, they choose another wheat variety with a desirable trait—say resistance to a certain fungus—and sprinkle its pollen onto the once-sheltered ovary. They arrange about 600 genetically different marriages like this each year.

Subsequent wheat generations are eventually planted in field trials around the state. Right now in Pendleton and Corvallis alone, there are about 40,000 genetically distinct lines. With luck, maybe one or two of them will make it to the market in five or six years, says Peterson, who also serves as the chair of the National Wheat
Improvement Committee.

One reason the process takes this long is that researchers have had to cross their fingers and wait until the harvest to see if the trait they want actually shows up in the wheat. If the trait involves resistance to a disease, it could take several years to determine its effectiveness.

OSU cereal geneticist Oscar Riera-Lizarazu, though, is trying to speed up this process through genetic mapping. Genetic mapping is a bit like using Google maps to find a gene on a spindly chromosome, except you can’t zoom in quite as much, so you have only a rough idea of where the gene is. What you can see, however, are genetic markers, which are sequences of DNA that are found near the gene you’re looking for. So if the markers are present, you can be almost certain that the gene is there.

The genetic mapping of wheat, however, is no small task. The wheat genome, the entire collection of genes, is five times bigger than the human genome, and it can take years to identify some markers, Riera-Lizarazu says.

Riera-Lizarazu’s lab has identified markers associated with genes responsible for extra-soft kernels and for resistance to several diseases. So if Peterson wants to know if wheat he’s growing has these traits, he’ll send some of its kernels to the lab where the DNA will be extracted and amplified. In only a couple of days, he’ll have the results. There are lots of traits, and Riera-Lizarazu has mapped markers for just a handful, so field trials are still necessary in many cases.

While developing new wheat lines, OSU’s researchers keep in mind what the market wants. “Behind everything we do, there must be a product at the end of the day,” Peterson says.

Andrew Ross
Andrew Ross, an OSU cereal chemist and bread explorer, tests the baking qualities of new wheat varieties in development at OSU. He explores the precise combination of genes in wheat that makes crusty bread, or slick noodles, or spongy cakes. Photo by Tiffany Woods.

That’s where Andrew Ross fits in. He and his team make noodles, bread, cookies, sponge cakes, and pancakes from the wheat Peterson breeds. He tests the kernels and dough for key traits like color and protein levels. One machine in his lab, for example, weighs kernels one by one, measures the moisture in them and crushes them to see how hard they are. Another device drops a miniature guillotine blade onto unsuspecting cookies to measure their tenderness. A third piece of equipment mixes a smidgen of flour and water, analyzes it, then prints out what looks like a violent seismogram that shows if the dough will be soupy during mixing and how long it takes to reach the optimal consistency. “We can eyeball these graphs and tell you—just like that—if we’re going to keep the wheat,” he says.

In the United States, wheat falls into six classes: hard red winter; hard red spring; soft red winter; hard white; soft white; and durum. Most Oregon-grown wheats are soft whites, which are generally lower in protein and make excellent cakes and cookies. Hard whites make good Asian-type noodles as well as bread. Hard and soft reds are also used in bread.

To make bread, you need to have flour with enough high-quality protein to hold the loaf together. To produce a high-protein content, it helps if the wheat is stressed late in the season by dry, hot weather. Oregon’s cool summers often don’t cooperate, instead producing more starch and less protein in the kernels, perfect for pancakes and pastries. Now OSU’s wheat-breeding program is working to develop hard wheat varieties better adapted to the Northwest’s climate. As it does, Ross wants to be there, ready with baguettes, boules, and bâtards in hand to show that, yes, hard wheat grown in the Northwest can make mouth-watering breads.

The timer on the oven beeps. Ross opens it and pulls out a loaf of toasted-brown, crunchy ciabatta. “Beautiful,” he says as he slides it onto a rack. “You can hear the crust crackling. When you hear the crackling, it’s like music. You think, Oh, I’ve done well.”


Web resources

Andrew Ross' blog Bringing food chemistry to life