Corn+Soybean Digest

How High Can The Pyramid Go?

Anyone not amazed at the pace of crop biotechnology simply has not been paying attention.

In the past few years, this science has advanced from the equivalent of a Model T to a powerful, loaded-with-options Porsche. Not too many years ago, early biotech researchers were using gunpowder to literally shoot foreign genes into plant tissue. Today they use high-tech gene guns to inject genes at precise locations.

In 1998, Garst marketed a hybrid that combined Liberty-Link and IMI (imidazolinone) herbicide resistance with Bt corn borer resistance and resistance to gray leaf spot. Other companies have hybrids with similar "pyramided" genetic traits.

At this point, there seems to be no practical limit of genetic traits that can be piggybacked on one hybrid or variety.

"We don't know how many different traits can be stacked in a single hybrid," says Dekalb's Tracy Klingaman.

"As we get deeper into quality traits, we may hit a finite limit on the number of traits that can be combined, but that's still a long way off. The learning curve for biotechnology is still trending steeply upward."

The marketplace will ultimately determine which traits will be combined in stacked products, Klingaman adds. Farmer acceptance in new technology depends on value. If the yield potential is there and the trait combination offers value to the grower, adoption is rapid.

"In 1998, Dekalb had one Roundup Ready-Bt stacked corn hybrid and will continue to provide additional stacked Roundup Ready-Bt hybrids in 1999."

Until recently, most transgenic traits have offered crop protection characteristics: herbicide tolerance and resistance to insects and diseases. Now companies are emphasizing crop-quality traits: high-lysine, high-oil, low-phytate hybrids that fill specific needs and uses.

"We have a white corn that incorporates Bt corn borer resistance; it also has a yield bump and superior milling characteristics," says Dan Hinderliter, Novartis corn products manager. "And we have popcorn and sweet corn with Bt resistance.

"Specialty traits are the wave of the future," Hinderliter adds. "A high-yielding, high-oil hybrid with Bt resistance has a lot of value for many growers. I think we will see specialty traits in crop production come on quickly."

Major seed companies have their sights set on the ultimate prize in crop specialization: "nutraceuticals." Plant scientists now have genetic materials that promise to literally turn cornfields into pharmacies producing medicines and vitamins.

Meanwhile, companies are expanding the crop protection front, too. There's little "been-there, done-that" attitude toward transgenic products already on the market. For example, EPA recently granted AgrEvo approval to market a new Bt agent to fight European corn borer.

"The StarLink Bt corn has a completely different protein, Cry9C, than Bt products (Cry1A) now in hybrids," says AgrEvo's Keith Newhouse. "It binds to a different site in the insect's gut, which should make this product less susceptible to any resistance buildup than the more commonly used Bt products. The two can be stacked in the same hybrids for maximum resistance."

It's still EPA's call, but the use of two Bt agents with different modes of action in the same hybrid should reduce the number of acres that need to be set aside as a refuge.

Also moving to front burners is western corn rootworm resistance.

"We are evaluating several solutions to the rootworm problem," according to Novartis' Hinderliter. "We'll be expanding our testing this next year, and hope to have a rootworm-resistant product on the market by 2000 or 2001."

Monsanto and Dekalb have about that same time line for their rootworm-resistant hybrids.

Scientists at major seed companies are still going back to the basics, too.

"We recently patented a yield trait that improves drought tolerance dramatically," says Dekalb's Klingaman. "We're testing it now. There's still a host of different things out there; we don't even know all of them yet.

"As you bring out a new trait, you still need to select inbred lines to incorporate that trait into. For example, we have two new Roundup Ready hybrids for 1999 that will be released in totally new germplasm."

Genetic manipulation and trait stacking should get big boosts from corn gene mapping. Pioneer Hi-Bred International and DuPont are completing an exhaustive plotting of the location and function of each of the 80,000 or so genes in a corn plant's makeup. Monsanto is close behind with its corn genome project, and Novartis has committed $600 million to a genome study.

These genetic road maps will let scientists insert genes more precisely so their traits can be more effectively expressed.

Prepare to be amazed all over again.

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