Although costlier than other seed corn choices, triple-stacked transgenic hybrids proved worth the added expense for Craig Weber, Arlington, SD, and many other western Corn Belt farmers last year.

“The triple-stacked hybrids were clearly our best yielding hybrids in 2006,” says Weber, who planted three biotech traits combined into one seed for the first time last season. “Its rooting power was very good. We had winds up to 45 mph and the corn still stood quite well.”

Yet Weber admits to having doubts about purchasing the biotech-packed seed prior to planting. “I wasn't sure if it would pay for itself, because it was considerably more money,” he says. “I had planted stacked hybrids with Bt corn borer and Roundup Ready since 2002 and they'd all done well. So, I thought I'd try the triple stack, which included the Bt rootworm control.”

Despite the higher initial expense for this seed, the overall cost was about the same as buying the double stacks he'd bought in prior years and applying a soil insecticide, says Weber, who planted nearly 60% of his corn acres to triple-stacked hybrids last year. He adds that 2006 was a dry year for corn growers in his area, and that Bt hybrid rootworm protection worked better for him than using a soil insecticide.

Biotech hybrids with a Bt rootworm trait do protect the corn plant's entire root system better than soil insecticides do, particularly in a dry year, agrees Ken Ostlie, a University of Minnesota Extension entomologist. If rootworms are present, then that extra protection can translate into significantly increased yields, he adds.

While still unsure about how many acres to plant to triple-stacked hybrids in 2007, Weber says he's pleased with the results from last year. “In a dry year, it helps to have the Bt rootworm corn,” he says. “It's given us a little more security during the droughty conditions we've experienced over the past few years.”

Biotech seed traits are gaining in popularity every year, whether the cropping year is wet or dry, according to Clarke McGrath, an Iowa State University agronomist with the Corn and Soybean Initiative, Harlan, IA.

“The multi stacks are really popular because, number one — they're price competitive, and number two — they work,” says McGrath. “The Bt rootworm component gives good drought tolerance, and the Bt corn borer trait helps limit ear drop and problems with volunteer corn. Both help to improve stalk strength and reduce lodging.”

In the Western Corn Belt, it's difficult to find much conventional seed being planted anymore, notes McGrath. “In many cases, even refuge acres are being planted to seed containing at least one biotech trait,” he says. “So, it's often field-to-field biotech crops.”

With a strong demand for corn from domestic ethanol producers and exporters alike, the higher expected corn prices in 2007 are fueling an even greater interest in multi-stacked hybrids among farmers this winter, says McGrath. That's particularly true in areas needing protection against corn rootworm when planting corn after corn, he adds.

“I think the multi stacks will become standard equipment eventually, and more stacks will be added in the future,” says McGrath. “It's probably easier to manage an inventory of just triple or quad stacks than trying to manage an inventory of single-, double-, triple- and quad-stacked hybrids.”

Additional acreage planted to corn will likely mean more stacked trait technology deployed in the field, agrees Andrew LaVigne, president and CEO, American Seed Trade Association (ASTA).

“As you look at the means to increase production and efficiency, farmers will rely on stacked traits increasingly in the future,” says LaVigne. “Research is ongoing that will help to improve nitrogen uptake and utilization, allow a greater tolerance for cold and moisture stress, and provide added convenience for weed and insect management. So as farmers increase their corn acres, they also will increase their use of stacked traits.”

In fact, early seed orders indicate that triple-stack seed sales may exceed 35% of all DeKalb and Asgrow brand corn seed sold, Monsanto announced recently. It also announced that “for the first time [these brands] will sell more acres of triple-stacked corn hybrids than hybrids with just one trait.”

Yet, concerns over too much reliance on transgenic traits abound as well, says Ostlie. “This tendency to package things together is going to drive overuse of transgenic traits,” he predicts. “For example, in the future you might not be able to find a rootworm-only trait or a corn borer-only trait as readily as a stacked trait. Or, you may end up with more transgenic insect traits than you need simply because it comes stacked with the herbicide resistance that you want.”

However, concerns over seed trait availability have yet to come to fruition, notes LaVigne. “Seed trait availability is driven by what growers demand,” he emphasizes. “Right now there is strong demand all across the board, whether it's for a single Bt corn trait or a multi-stack.”

Still, consumer demand has made a negative difference in the Eastern Corn Belt, where triple-stack corn hybrids aren't as popular as in the Western Corn Belt, points out Bob Nielsen, Purdue University Extension agronomist. “In the Eastern Corn Belt, where food processors purchase much of the corn, grain-buyer acceptance of biotech crops is still a hurdle,” he says. “Some buyers won't accept certain transgenic hybrids because they aren't yet approved for the European market.”

Another reason farmers may choose to purchase the triple stack less often in the Eastern Corn Belt is that the European corn borer has yet to establish itself as a perennially severe pest in Indiana and Ohio, says Nielsen, who adds that the Bt corn borer technology was initially cost-prohibitive for many farmers.

“When Bt corn borer first came out it had an $8-10/acre premium,” he says. “It's much less expensive now. You can almost get it free when it comes triple stacked. It's down to about a $2/acre premium.”

Because the Bt corn borer technology fee has dropped so significantly over the last few years, more Eastern Corn Belt farmers are considering the triple stack, if they can find a buyer who is willing to accept it, says Nielsen. “It's an insurance policy for something you don't need very often.”

There is no shortage of any high-yielding seed corn, whether in non-transgenic, single- or multi-transgenic traits, says Nielsen. However, if the seed industry puts less effort into breeding non-transgenic seed lines, “all the good-yielding material might come out in transgenic hybrids,” he points out.

Another possibility would be that seed companies only offer a small portion of non-transgenic counterparts to their newest biotech hybrids, he says.

The market always responds to consumer demand, reassures LaVigne. He likens the choices available in the seed industry to the choices available in the car industry. Certain features come standard and others are optional, depending on what consumers want.

“So as seed traits continue to evolve, seed companies will also continue to provide an array of product choices,” LaVigne says. “Ultimately, the new traits are being driven by the farmer, but in other cases it's the Krafts, the McDonald's and ADMs of the world and what they're demanding.”