New Soybeans Mark Exciting New Era

By for CAES News
A Georgia marriage of old and new technologies has smashed a plant-breeding record of sorts, taking new soybean varieties from zero to commercial reality in less than five years.

"That's light speed for a breeding endeavor," said Roger Boerma, the University of Georgia plant breeder whose team accomplished the feat. "Thirty years ago, it took 12 years to develop a new variety. From the mid-1970s, it has required eight years."

The scientists cut three more years off the time farmers must wait for a new variety, though, with the help of two key partners.

Two Key Partners

They knocked off two years with DNA instrumentation developed by scientists and engineers to sequence the human genome and provided to UGA by the Georgia Research Alliance. Then the Georgia Seed Development Commission, led by director Earl Elsner, provided for winter seed increases that trimmed off another year.

Photo: Scott Bauer, USDA-ARS

They're just little, round beans, but there's nothing simple anymore about the way soybeans get from the scientist's lab to the farmer's field.
As a plant breeder, Boerma is rooted in traditional methods scientists have proven in the past. But he's not averse to the new marvels of genetic technology. The opportunity to combine the two presented itself in 1996.

That's the same year Monsanto made Roundup Ready soybean seeds available to soybean growers. A single gene, which Monsanto had inserted from a soil-borne bacterium into soybean plants, made the plants tolerate the herbicide glyphosate.

Glyphosate Tolerance

Glyphosate, the active ingredient in Roundup, controls just about every weed in soybean fields. It kills soybeans, too, unless the variety has the new glyphosate-tolerance gene. With soybeans possessing the gene, growers can spray glyphosate over the top without hurting the variety's yields.

"It gives them a 30-day application window, not the five- or six-day window they had before," Boerma said. That's important, he said, because of the nature of the crop for Georgia farmers.

"There's a lot of stress on farmers," he said. "They have to have large, efficient operations. And soybeans have never been their most important crop. It's always been the stepchild."

Overnight Adoption

Almost overnight, Georgia soybean growers made it clear they considered the single genetic trait vital to them. "We were astonished at how fast growers went to the new technology," Boerma said.

In the spring of '96, farmers began abandoning seeds that cost them around $12 per acre for the new Roundup Ready seeds at double the cost. In just four years, traditional varieties fell from 100 percent of the crop to 15 percent.

The new varieties gave growers the weed control they wanted. A pristine green corduroy of soybean rows filled their fields. But their harvests weren't satisfying. And declining soybean acreages dropped further in Georgia, from 650,000 acres in 1992 to about 200,000 in '99.

Cloud in the Silver Lining

The problem, Boerma said, is that the initial high-tech varieties, bred in the Mississippi Delta, didn't perform as well as traditionally bred UGA varieties, except for that one trait. They weren't bred for Georgia's climate. And they didn't have the key pest resistances bred into UGA-released varieties.

"The growers ended up with less yield than they hoped for," he said. "Their profit-loss margin is razor thin to start with. If they spend more for seeds and don't get better yields, it's very frustrating."

In May of '96, though, the UGA College of Agricultural and Environmental Sciences acquired the glyphosate tolerance gene from Monsanto, Boerma said. The CAES team immediately began a backcross breeding program to bring the gene into UGA varieties Boggs, Haskell, Benning and Prichard.

High-Tech, High Speed

In late 1997, a new DNA marker system became available to speed up the process. With the high-tech equipment of the GRA-funded Applied Genetic Technology Resource at UGA, the scientists quickly identified lines that combined glyphosate tolerance with the UGA varieties' best traits.

Then, each time they backcrossed the hybrid with the original UGA release, they used the DNA markers to pick precisely the best plants for the next backcross.

"Usually it takes five or six backcrosses to complete the process," Boerma said. "At best, you can breed two generations in a year."

With the help of the DNA markers, though, the scientists produced glyphosate-tolerant plants almost exactly (99 percent) like the superior UGA varieties in just three backcrosses and less than three years.

Early UGA Releases

Two GSDC-funded winter seed increases in Puerto Rico then helped get enough seeds to set the first two UGA glyphosate-tolerant variety releases (from Benning and Prichard) in February 2001. (Boggs and Haskell will be released in 2002.)

That's three months less than a five-year process.

"That speed came through the marriage of a traditional, proven breeding program with DNA technology," Boerma said. "And the technology is species-blind. You can do the same thing with other crops or even apply it to the improvement of animals. It's no longer a matter of promise. It's here now."

Dan Rahn is a news editor with the University of Georgia College of Agricultural and Environmental Sciences.