Technology helping develop new bean varieties

A Georgia marriage of old and new technologies has taken new soybean varieties from zero to commercial reality in less than five years.

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

The scientists knocked off two years with DNA instrumentation developed by scientists and engineers to sequence the human genome and provided to the University of Georgia by the Georgia Research Alliance.

Then, the Georgia Seed Development Commission, led by director Earl Elsner, provided for winter seed increases in Puerto Rico that cut another year.

As a plant breeder, Boerma is rooted in traditional, proven methods. 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 growers. A single gene, which Monsanto had inserted from a soil-borne bacterium into soybean plants, made the plants tolerate glyphosate.

The active ingredient in Roundup - glyphosate - controls many weeds in soybean fields. It also kills soybeans, unless the variety has the new glyphosate-tolerant gene. With soybeans possessing the gene, growers can spray glyphosate over the top without hurting the variety's yields.

Almost overnight, Georgia soybean growers make it clear they considered the single genetic trait to be vital. In the spring of 1996, farmers began abandoning seeds that cost them about $12 per acre for the new high-tech seeds at double the cost. In four years, traditional varieties fell to 15 percent of the crop.

The new varieties gave growers the weed control they wanted. But their harvest were not satisfying. And declining soybean acreage dropped further in Georgia, from 650,000 acres in 1992 to about 200,000 in 1999.

The problem, says Boerma, is that the initial high-tech varieties, bred in the Mississippi Delta, didn't perform as well as traditionally bred University of Georgia 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 University of Georgia-released varieties.

"The growers ended up with less yield than they had hoped for," he says.

"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 1996, the University of Georgia acquired the glyphosate-tolerant gene from Monsanto, says Boerma. The CAES team immediately began a backcross breeding program to bring the gene into the University of Georgia varieties Boggs, Haskell, Benning and Prichard.

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," says Boerma. With the DNA markers, the scientists produced glyphosate-tolerant plants 99 percent like the superior UGA varieties in just three backcrosses.

The two Puerto Rico seed increases then helped to get enough seeds to release the first two UGA glyphosate-tolerant varieties (from Benning and Prichard) in February 2001, three months less than five years. Boggs and Haskell will be released in 2002.

"That speed cam through the marriage of a traditional, proven breeding program with DNA technology," says Boerma. "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."

Sponsors for this year's Southeast Cotton Conference include John Deere Co., which will be providing the lunch; Monsanto Company the breakfast; and Stoneville Pedigeed Seed Co., which is providing refreshments during the breaks

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