On a blustery June day, officials cut the ribbon on Bayer CropScience’s new wheat breeding centre near Pike Lake, Saskatchewan. But the wheat varieties coming out of that research station south of Saskatoon will be unlike other varieties grown in Western Canada, as the company is developing hybrid spring wheat varieties in Saskatchewan.
Today’s wheat varieties are the result of self-pollination of inbred wheat lines, David Bonnett explained during the research centre’s open house. Bonnett leads hybrid spring wheat breeding efforts in North America for Bayer.
When varieties are created from inbred lines, each generation is the same as the parents. That makes it possible for farmers to save their own seeds year to year, although plant breeder rights restrict that practice on some varieties.
Hybrids result when two genetically-distinct lines are cross-pollinated. Unlike the seed from pure lines, seed from hybrid varieties generally isn’t saved, as the plants will revert back to the parent varieties.
Other seed companies are developing hybrid wheat programs as well. While a few hybrid wheat varieties have been available commercially in Australia since the 1980s, yield gains did not outweigh production costs, according to Australia’s FarmOnline.
It’s a more complex way to breed wheat, said Bonnett. Plant breeders need to develop a wheat line that doesn’t produce pollen, and therefore any anthers. A second line produces the pollen. The hybrid spawned by those parent lines must be completely fertile.
“That’s biologically quite a challenge,” said Bonnett. But breeders have created sterile lines to receive the pollen. They’ve also developed lines with anthers that protrude from the wheat head so the pollen travels far enough to fertilize the other line.
In the beginning of a hybrid wheat program “the hurdles are much, much higher,” said Marcus Weidler, head of seeds for Canada. That means a larger initial investment, he said — a total of $1.9 billion over 10 years in the global wheat breeding program.
So why focus on hybrids? Bonnett said hybrid varieties yield higher and have more stable yields across environments. They also show substantial increases in vigour, he said, an important trait given Western Canada’s short growing season.
Weidler said plant breeders can also speed up genetic gain in a hybrid program, something Bayer has seen with its other hybrid programs. Because the male and female lines are only combined when seed is produced for farmers, breeders can just test what comes out of those lines, he explained.
How much faster will it be to develop hybrid wheat varieties?
“Honestly, we don’t know,” said Weidler. “It could be two years. It could be three years. We’ll figure it out while we go.”
Bayer expects its first hybrid spring wheat varieties to hit the market in six to eight years.
Goals of the wheat breeding program
The objective is to produce wheat hybrids that help farmers be more competitive in the market place and also help feed the world, said Weidler.
Bayer decided a few years ago to focus on a hybrid wheat program, Tom Zatorski, a wheat breeder based in Saskatoon, told delegates during a tour of the facility.
“And what that meant for the Canadian spring wheat breeding program is we went from a variety development program to a line breeding program that supported our hybrid effort.”
But, Zatorski said, breeding targets are relatively similar in a hybrid program. The main goals in either program are to develop a very high-yielding, and stable-yielding, wheat.
Breeders are also looking at disease resistance. In Western Canada, that means focusing on pathogens such as leaf and stem rusts, striped rusts, leaf spotting complexes, and fusarium head blight, he said. Plant breeders are using DNA markers to select for natural traits, he said.
Bayer employees make the first crosses at the company’s greenhouses in Saskatoon. Greenhouses are also used to increase the seed and to get three growing seasons. They can also send material to New Zealand to grow in the winter, Zatorski said.
Material is then sent to the field nurseries near Pike Lake. Bayer has 480 acres near the South Saskatchewan River to work with.
“It’s on a clay loam. It holds moisture. We can grow a decent crop without a lot of rain. But at the same time it’s very well-drained,” said Arling Kemppainen, agronomist for Bayer.
Each quarter has centre-pivot irrigation, which helps ensure even germination so they can meet seed production goals. They can also use the irrigation for disease work, Kemppainen said. Bayer also does canola agronomy work at the site, he added.
Wheat breeders started out with 108 plots in 2013 at Pike Lake. In 2016, they had about 6,000 plots on the site, Zatorski said, at various stages.
When plant breeders first get material from the green houses, they only have about 20 grams of seed to plant in the field, Zatorski said. They need to multiply that seed to kilograms, so they have enough material for yield testing trials across Western Canada.
Field performance isn’t the only thing Bayer is measuring. Because they’re targeting the CWRS and CPS classes, “quality is very important to us,” Zatorski said. That means a high protein and a variety with a good end-use functionality.
Rhett Kaufman is Bayer’s wheat quality manager, based in Nebraska. The Saskatchewan facility will be testing early-generation material, he told delegates. In addition to quality labs in Saskatchewan and Nebraska, Bayer also has quality labs in Germany and Australia.
Breeders send Kauffman about a pound of wheat. He can them make white flour with a small flour mill. In this early stage, staff will be testing thousands of lines a year, between labs in Saskatchewan and Nebraska, Kaufman said. The goal is to pare down those numbers before the material enters yield testing as potential parent lines.
Early generation material must pass protein specs. Staff also measure falling number, kernel size and hardness, and sedimentation volume, Kaufman said.
The wheat also has to pass the mixograph test, to make sure it maintains gluten strength even if it’s overmixed. The mixograph is “a very strong, very robust, harsh mixing action. It puts a lot of stress on the wheat.”
Kaufmann follows guidelines set by Canada’s Prairie Grain Development Committee. “Quality is one of the most important factors, if not the most important factor, when it comes to registering a variety of wheat in the Canadian system,” he said.
Asked whether the Canadian grading system creates more challenges for the wheat breeding program, Kaufman said it does and it doesn’t. Varieties are scrutinized more, but there’s also a clear target, he explained.
“If it falls within that window, it’s going to be in that class.”
Other places allow varieties that are within an acceptable quality range, he said, but that’s not where he wants to see Bayer’s varieties.
“We’re kind of using (the Canadian model) as a model for our other North American programs, and saying ‘This is where we want to fall.”