Tapping the Wild Side of Wheat

Just as geographic information system (GIS) technology transformed planting and harvesting, advancements in DNA-driven seed production are revolutionizing seed choices. For wheat growers, predictive breeding using DNA is getting new seed varieties to market faster and is on a path to increasing end-user specificity and on-farm profit opportunity.

According to Paul Morano, head of North American cereals for Syngenta, using DNA markers to confirm traits in existing wheat strains eliminates multiple generations of hit-and-miss field trials that were the norm.

“Today, we can look at 100 wheat tissue samples and find the ones that have the DNA string we want,” he says. “We know for a fact it’s in there.”

From there, confirming that the trait was picked up when the cross was made simply requires a DNA test.

Today, we can look at 100 wheat tissue samples and find the ones that have the DNA string we want.

“So, there’s a huge difference in the number of plants, the number of trials and the amount of labor you need,” Morano says. “It’s much, much better than the way we were doing it before.”

Although technology such as CRISPR — clustered regularly interspaced short palindromic repeats — further reduce the timeline by allowing scientists to manipulate the plant’s DNA in a lab versus in a field, the U.S. Department of Agriculture (USDA) currently prohibits genetic modification of wheat through a non-natural process. Genomic editing is often defined as changes made within a plant’s own DNA, with genetic modification defined as the insertion of a gene.

“That’s where the crux of gene editing comes in, because there is no genetically modified wheat; GM wheat is not accepted,” Morano says, adding that even the definition of genetic modification is a gray area. Some interpret it as the insertion of genes from one species into another, while others apply the term to any artificial movement of genes, even same-species transfers.

The Search for Consumer Acceptance

That’s a frustration for Dave Milligan, Michigan farmer and president of the National Association of Wheat Growers.

“Wheat’s kind of fallen behind some of the other crops as far as the technology other crops have used,” he says. “Consumers are resistant to products produced by genetic modification, and it’s really been detrimental to moving wheat research ahead, wheat breeding particularly.”

Milligan hopes the precision of CRISPR will result in wider acceptance of the technology, and he appreciates the gains being made in that arena.

“We’re growing a lot more bushels on a lot fewer acres than we were 50 years ago,” he says. “They have made improvements, and we need to continue to do that.”

Morano says Syngenta continually breeds for increasing yield and disease resistance, but those aren’t the only goals in the breeding program. Breeders also test for consistent performance under a variety of conditions and increased flour quality. They also research gluten properties to improve digestibility.

“Growers want yield, but I think another thing they want is consistency,” he says. “Wheat is grown on some tough acres, and in many places, you can grow a good crop if conditions are right; but when conditions change, your crop goes bad in a hurry. So, farmers want — need — consistent performance.”

Another focus in breeding is finding DNA markers for wheat quality attributes that will improve, and perhaps define, the final flour product.

“That’s important, because then you can breed for a specific end use, whether that’s a bread, a cracker or a cookie,” Morano says. “So that’s one thing a lot of people are working on.”

Another is gluten, the substance that provides the viscoelastic properties that give rise to bread but can also cause problems for those with celiac disease. Allan Fritz, Ph.D., a professor of wheat breeding at Kansas State University, says while a celiac-safe wheat may not be possible, identifying problematic proteins in gluten is a realistic target.

“As a research community, we could look at whether we can make that gluten less reactive in the digestive system so people are less likely to develop sensitivities,” he says.

Wild Relatives’ Promise

Breeders are exploring the vast resource of “wild relatives” — naturally occurring wheat species — to improve commercial varieties. Fritz notes that these wild relatives give breeders access to unique genetics that are not currently available in commercial varieties.

“Only a handful of those plants were involved in the hybridizations that led to modern-day wheat,” he says.

Researchers, including Fritz and the team at the USDA’s Hard Winter Wheat Genetics Research Center in Manhattan, Kansas, are exploring what the wild species of wheat can contribute to commercial production goals for wheat varieties.

The research already shows that wild relatives can contribute disease and insect resistance, as well as nutritional traits that would make a healthier crop. One of the most promising, Fritz says, is wild emmer, an ancient grain native to Israel that shares 28 of domestic wheat’s 42 chromosomes.

“If we could redomesticate these plants, we could give people something that is actually better for them — better antioxidant capacity, or better iron and zinc nutrition, which is needed in some parts of the world,” Fritz says. “I think there’s a story there, about this natural goodness in the grain we’re providing through these new materials. If we can make things that really are better for people from a health standpoint, there’s a tremendous amount of value in that.”