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Yield/Trait debate

“The three most important traits to use in corn hybrid selection are yield, yield and yield,” says University of Minnesota agronomist Dale Hicks. “Yields pay the bills, and unlike with soybeans, there aren't a lot of other traits you need to consider.”

Although Hicks's bold statement would have been accepted as just good common sense a few years ago, today it implies that farmers enamored with the latest trait technology don't always get the best value for their seed dollar. It also suggests that seed companies, despite their best efforts and significant improvement in reducing yield drag, don't always have a genetically modified (GM) trait-added hybrid that can yield with the best elite conventional hybrids in all growing conditions.

Regardless of what GM traits are added, the base genetics that determine hybrid yield potential still vary widely from one hybrid to another, especially within specific growing areas. The difference between the highest- and lowest-yielding hybrids is commonly 40 to 50 bu./acre, Hicks says. Based on that spread, he thinks a farmer who selects only the top-yielding hybrids for planting can reasonably expect an average boost in corn yields of 10 bu./acre.

Hicks also points to the high price of seed as another reason to scrutinize hybrid yields. With trait-added hybrids exceeding $170/bag, the cost of seed corn now approaches fertilizer cost as a direct expense. If you pay that much for seed, you had better need those traits, and most importantly, yields had better perform. The philosophy might be summarized as “yield first, then traits.”

Seeing a difference

The yield-protective characteristics of a corn borer-resistant or rootworm-resistant GM hybrid should help that hybrid come out as a top yielder. But because farming is a long-term endeavor dependent on variable conditions each year, it can take years to see the true value of a trait. Unusual weather patterns or pest populations that boom and bust can make it virtually impossible to evaluate a hybrid or trait with just one year's data. It takes long-term yield data to make a strong case. It took several years of collecting yield data, for example, for university agronomists to determine that corn borer-resistant Bt hybrids deliver an average yield advantage of more than 7 bu./acre over conventional hybrids.

Corn rootworm conundrum

Long-term, multiyear results are the ones that matter. Still, when all you have is one year of data, as is the case with new corn rootworm (CRW) hybrids, it is tempting to try and understand what it means. In 2003, with just one year of data and a limited selection of hybrids to test, the CRW hybrids apparently didn't fare as well as non-CRW hybrids. When University of Wisconsin corn agronomist Joe Lauer compiled university corn yield data that included CRW hybrids in seven Midwest states, he found that the CRW hybrids beat the trial average only 33% of the time and actually averaged significantly less yield than non-CRW hybrids.

Lauer is quick to point out that a one-year snapshot of data on the new CRW technology can't be extrapolated into assumptions on future yield performance. But the disappointing one-year results do seem to indicate that some farmers who jumped into the new trait too aggressively paid a price in reduced yield.

“The Bt-CRW technology offers exciting new possibilities for control of this insect,” Lauer says. “Seed companies are working to incorporate this technology into their commercial hybrids. Few hybrids were entered into university trials in 2003. I found a total of 13 Bt-CRW hybrids tested in seven states.”

Lauer's table (above) shows the performance of CRW hybrids in relation to trial average. The trial average for all locations was 189 bu./acre. Across all locations, Bt-CRW hybrids produced 5.7 bu./acre less than the trial average. At seven of these locations, where corn followed corn, Bt-CRW hybrids yielded 8.2 bu./acre less than the trial average of 195 bu./acre. In 18 of 54 trials (33%), the Bt-CRW hybrid beat the trial average.

If not yield drag, then what?

When seed companies first started shooting genes into hybrids, agronomists noticed a phenomenon that they termed “yield drag.” Sometimes the conversion process scrambled the hybrids' genetics to the point where yield suffered. Seed companies soon learned how to overcome the yield drag problem with clever selection techniques during corn inbred conversion. Today, it's generally accepted that farmers shouldn't have to worry about yield drag on their GM hybrids.

So what went wrong on CRW yields in 2003? And with the comments of university agronomists like Hicks in mind, do farmers need to choose between the traits they want and the yield they need? We asked the representatives of the three largest seed companies to weigh in on the subject.

NK Brand

“One thing we have to consider on CRW hybrid yield data is that there are plenty of other good options for controlling rootworms,” says Bob Navratil, NK Brand technical information and training manager for Syngenta Seeds. “Farmers can choose from a wide selection of soil-applied or seed-applied insecticides that provide excellent protection from the pest and protect yield. If a farmer doesn't plant a hybrid with the CRW trait, he'll probably go with one of the other options and get good results.”

But that consideration alone should put CRW hybrids on par with non-CRW hybrids, not at a yield disadvantage. To explain the 2003 data, Navratil says the most likely reason for lower-yielding CRW hybrids is that the trait just wasn't available in a wide enough range of hybrids and maturities for proper on-farm hybrid positioning.

“If we look back a few years, we saw a similar problem for growers who were first to try Bt corn borer-resistant hybrids,” Navratil says. “Availability of hybrids with the new trait was limited, so seed dealers weren't able to match the best genetics and maturities to every customer's field.

“Many growers saw the value in the trait and were eager to try it,” Navratil continues. “Some planted Bt hybrids that were the wrong maturity just so they could try the trait, so of course that hurt yields. As more hybrids with elite genetics became available with Bt, yields improved because farmers could get the right genetics for their field as well as the yield protection of a Bt. Today, nearly 70% of Syngenta's NK Brand corn hybrids are sold with Bt corn borer resistance, and the yield protection advantage of the hybrids has been well documented.”

It seems likely we will see the same type of improvement with CRW in upcoming years. Numerous trials looking at root scores indicate that the CRW trait provides unbeatable protection against corn rootworm feeding. That protection, paired with the right genetics for a farmer's growing conditions, should ultimately translate into higher yields.

“It's really not a case of yield versus traits,” Navratil says. “It's about choosing the right genetics. Farmers and their dealers need to work through numerous agronomic characteristics that can contribute to yield, matching strong emergence hybrids to no-till situations, for example. Or strong stalks to disease-prone or windy areas, good drydown when there's a short season because of late planting, and a host of other agronomic characteristics that all contribute to yield. Once you've got the right genetics, adding traits to protect yield makes sense in the right situations. And it takes a knowledgeable seed dealer, working closely with the farmers to position the right hybrids on each particular field.”

Pioneer Hi-Bred International

“Hybrid placement is key to performance,” says Mike Dillon, a field sales agronomist with Pioneer Hi-Bred. “A good sales rep knows his customers and will know, for example, that feedlot producers tend to plant more corn on corn and may need to pay particular attention to corn rootworm problems. Providing protection with the right hybrids for each field may require a combination of soil insecticides, seed treatment or CRW trait hybrids.”

In a world where new gene technology is coming to the market increasingly fast, Dillon says sometimes you have to use “old” technology to find the right genetics for a field. “Converting an elite hybrid takes time,” Dillon says. “And Pioneer won't release that new trait hybrid until it does yield as well. You might say we will release no hybrid before its time.”

Nevertheless, being first to market with a particular trait/hybrid combination can be a tremendous competitive advantage for a seed company, and the companies are doing everything they can to shorten the selection process. Techniques such as marker-assisted breeding let corn breeders know in advance if a trait was successfully transferred without having to wait an entire growing season to see the results. Increasingly, new hybrids will come to market with traits already inserted and the conversion process fully completed. With that system in place it doesn't matter whether a hybrid comes with one trait, two traits or triple stacked with corn borer resistance, rootworm resistance and glyphosate tolerance. The hybrids can debut with a mix of traits without any yield drag penalty.

Ultimately, the decision of whether to plant a trait-enhanced hybrid boils down to what makes financial sense. Kyle Whitaker, technology launch manager for Pioneer, says the farmer's primary consideration should be getting the right genetics first and then finding the combination of traits and conventional pest control that makes sense for him. “The price of a bag of CRW hybrid seed reflects the value that the farmer receives from that added trait,” he says. “It may look high priced until you realize the other inputs you are displacing plus the convenience and safety of not having to handle as many pesticides. The added trait is just one component of a hybrid's overall value. Another way to think of an insect-resistant trait like CRW is that it can limit risk and preserve yields, just as a conventional agronomic characteristic like drought tolerance can.”

Monsanto Company

Lee Quarles of Monsanto emphasizes that careful screening by seed companies has virtually eliminated concerns about yield drag and farmers today don't have to choose between yield and traits. “We have seen an increased effort by seed companies to combine these biotech traits with their best-performing germplasm,” Quarles says. “This means that growers typically get the best of both worlds in one seed. I don't think this was always the case, so that is one reason why ‘yield performance’ was often inappropriately tied to the ‘trait’ and the reason why there was a lot of coverage of this in the past.” Today, Quarles says, farmers are looking at reduced input expenses, including chemicals, the farmer's time, and trips over the field, as factors to determine the overall profitability of trait-enhanced hybrids.

Based on their buying preferences, farmers would appear to agree with Quarles. In 2003, the National Corn Growers Association reported that 40% of all corn acres in the U.S. contained at least one GM biotech trait and 4% contained at least two GM traits. And though most farmers say they dislike the idea of paying a tech fee, a growing majority are paying extra for traits because they preserve yield, add convenience and can reduce pesticide expenses and trips across the field. The traits are in such demand that Monsanto, which has developed and broadly licensed more patented traits than all other seed companies combined, recently announced to its seed licensees that it would raise the royalty fees it charges on certain traits. Such pricing opportunity seems proof enough that GM traits make financial sense to farmers.

But can three traits in one hybrid make financial sense? In the right situations, yes, Quarles says. “When evaluating and selecting varieties, the overall economic, agronomic and pest management values should be assessed and considered for each individual hybrid — conventional or biotech,” Quarles says. “This depends on what characteristics growers are looking for as they head into planting, and this decision needs to be based on what pests are around or in their fields.

“For years, farmers have told us they don't want to have to choose between weed-control and insect-protection options. This is a primary reason why we will provide growers with the traits they desire in one seed — YieldGard Plus with Roundup Ready Corn 2, for example.”

Quarles says Monsanto continues to see the strongest growth in the U.S. in its corn traits business, especially stacked-trait technology offerings. In 2004, the company saw some shift in Roundup Ready single-trait corn offerings to its stacked-trait offerings.

The table on page 30 shows that the seed and pesticide input costs for a triple-stack hybrid can be higher, $9.60 more per acre than for the conventional hybrid in this example. But input costs tell only part of the story. Monsanto takes the position that other tangible benefits make the extra cost worth it. Quarles cites Monsanto data that show higher yields of 8 to 10 bu./acre due to better insect control with YieldGardPlus and crop safety with a Roundup glyphosate herbicide program. Quarles points to other benefits, including less insecticide to handle, reduced fungal infection and mycotoxins, easier harvest due to less lodging of corn due to corn borer and rootworm, and more flexibility in weed-control systems.

Your best bet is still yield. If past trends are any indication, farmers are going to continue snapping up new trait hybrids as quickly as they become available. For maximum profits, they still need to keep a focus on selecting the highest yielders. While some yield winners may be trait-enhanced, others may be conventional.

Hicks says hybrid yield comparisons, such as the Iowa performance trials, show that the average yield of the most widely grown eight or nine hybrids within each maturity group is about the same as the average yield of all 180 or so varieties. “This tells me that you should be able to beat the average with judicious hybrid selection,” Hicks says. “I can't tell you which variety will be the highest next year, but you can't go wrong by basing your selections on the highest-yielding varieties in each maturity group.

Performance of Bt-corn rootworm (CRW) hybrids in university performance trials during 2003

State Average yield of Bt-CRW hybrid compared to trial average Corn following corn locations (bu./acre) All locations (bu./acre) Trial average all locations (bu./acre) Number of times CRW hybrid beat trial average
Iowa -6.9 182 0 of 7 districts
Illinois -1.0 197 7 of 17, 1 tie
Nebraska -13.8 -20.8 223 0 of 8
Michigan -7.3 -9.1 202 0 of 3
Missouri None +2.1 100 4 of 6
North Dakota +10.1 148 2 of 2
Wisconsin -0.6 -7.5 193 5 of 11
All locations -8.2 -5.7 189 18 of 54, 1 tie (33%)
Data compiled by Joe Lauer, University of Wisconsin

Triple-stack versus conventional costs

Conventional corn YieldGardPlus with Roundup Ready Corn 2
Seed/acre $30.00 $59.31
Herbicide/acre $29.56 $25.85
Rootworm insecticide/acre $15.00 0.00
Total cost/acre $74.56 $85.16
Difference $ 9.60/acre
Compiled by Monsanto Company using Doanes for herbicide costs
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