Corn's Big Challenge

January 10, 2009 05:46 AM


We've tinkered with corn for more than 5,000 years. Now, with the mysteries of the corn genome becoming known, can scientists push yields to a quantum leap in a couple of decades?

Some researchers expect corn yields to climb at an unprecedented rate. Monsanto Company scientists predict a doubling of the average national corn yield by 2030. Their counterparts at Pioneer Hi-Bred International Inc. say corn yield should increase 40% during the next decade. Not everyone in the lab agrees, however. Some believe the corn yield trendline will continue on its steady climb but not accelerate much.

Either way, driven by an increasing demand for food, fuel and industrial uses, it's clear the world needs more corn. Plant breeding is mankind's ultimate blend of art and science.

It's no coincidence that the brain center of the cutting-edge corn breeding work is located in central Iowa on some of the world's best corn-producing soil. Here, between Des Moines and Ames, the top corn breeders for Monsanto, Pioneer and Syngenta do mind-boggling work in their plots, greenhouses and labs.

"There's phenomenal technology, and the experts tell us they've just scratched the surface. I believe yields are going to grow at an ever-increasing rate," says Craig Floss, Iowa Corn Growers Association CEO, who works in Johnston, Iowa.

Visit Ted Crosbie at Monsanto's modest-looking Ankeny complex, Dave Bubeck at Pioneer's college-like campus in Johnston or Ben Hable at Syngenta's corn headquarters at the former Garst Seed Company center near Slater, and you find corn breeders doing key research that was unthinkable just a few years ago.

Crosbie, Monsanto's vice president of global plant breeding, thinks pushing the national average corn yield to 300 bu. per acre by 2030 is doable. "Three-hundred-bushel corn is not hard. What's hard is to do it on 90 million acres. It's definitely possible," he says.

"It's a lot about the bottom side. We need to raise yield on the bottom half of the acres in the U.S. The hardest half to move is the top because there are biological limits. Four-hundred-bushel to 500-bu. is the theoretical maximum. We can produce 350-bu. to 400-bu.-per-acre corn now under very specific circumstances," Crosbie says.

The best way to pull the bottom end up is with drought-tolerant and nitrogen (N)-efficient corn, he explains. If drier corn producing areas such as eastern Nebraska, the Dakotas and the Texas Panhandle could leapfrog yields thanks to new technology, it makes the national 300-bu.-per-acre yield goal easier to fathom.

"What you need to do is get them to 200 bu. If you can bring them up 100 bu. from where they are solves half of our problem," Crosbie says.

The first technology to address that is in the pipeline, he adds. Going hand-in-hand with the new technology will be planting at higher populations.

"If we maintain the same grain per plant and double plant population to 60,000 plants per acre, we can produce 450-bu. corn, and it'll take less N per bushel," Crosbie predicts. "We will double yields with one-third less inputs per unit produced.

"This all depends on how fast we can demonstrate to farmers that they can plant 40,000 plants per acre and beyond. Some are afraid there will be stalk lodging and increased disease. We have to demonstrate that certain hybrids can do it," Crosbie says.

Monsanto breeders don't intend to redesign the corn plant, just make it more density-tolerant. "We need a plant that stands and has photosynthetic capacity right through black layer. That's why fungicides matter so much. Corn is a pretty simple plant. We have transgenic solutions to the major insect pests. As we remove one limitation, we discover what the next one is and work on it. I think doubling corn yield is going to go faster than 2030," Crosbie says.

With technology like a chipper that removes a tiny slice of a seed for DNA testing, Monsanto's Ted Crosbie is confident genetics can help corn yields reach 300 bu. per acre by 2030.

Bubeck, Pioneer's corn research director, says his company targets a 40% national yield increase throughout the next 10 years.

"That's never been done with any crop in the world over a 10-year period. It's possible. Is it a huge challenge? Absolutely. It's an enormous challenge and a big goal," he says.

With hybrids currently available, yields have stabilized under stress and steadily increased from year to year. Bubeck notes that the 2005 drought did not cut yields as much as the 1988 drought and that corn yields were generally good in 2008 despite extremely wet conditions in the Midwest.

"The top-end yield is more predictable. The increase comes from the bottom up. We're 10 years past the introduction of Bt for European corn borer control. Post-1997, the weather has had wide swings, but corn yield has not," Bubeck says.

In one of Pioneer's Johnston, Iowa, greenhouses, Dave Bubeck says he anticipates national corn yields increasing 40% in the next decade.

For the immediate future, Pioneer is developing its elite genetic improvements, much of it through what could be called traditional plant breeding programs accelerated by a coordinated global effort. By the middle of the next decade, Bubeck says, drought-tolerant and N-efficient hybrids should be available.

Pioneer's approach aims to remove a crop's limiting factors such as disease and insects. Plant population, though, is also a consideration.

"We're looking at what's profitable over the given conditions of 20" and 30" rows. A lot of yield gains over the past 50 years have been due to increased tolerance to density. If they're placed far apart, average yield per plant hasn't changed much over the years.

Old hybrids could flex just as well. It's about plant density, architecture, more compact plants that are responsive to yield at higher densities," Bubeck says.

"Physiology says the best way to get more yield is to get more things per acre. The number of kernels is more important than their size. We've looked at extremely high densities in developing new inbreds. Will we develop genetics more responsive to higher conditions, to 45,000 to 50,000 plants per acre? What's the downfall? Spindly plants? Or, if we are still at 30,000 plants per acre, will this new plant be a disadvantage?" Bubeck says.

Hable, Syngenta's head of NAFTA corn product development, is reluctant to predict where corn yield will be in a decade or even two. He just knows that the effort to push yields up is intense.

"Resources put toward genetic improvement have gone up exponentially in 20 years. With molecular markers, what we did in a month five years ago we do in a day today. Without a doubt, this will continue to increase," Hable says.

"Within Syngenta, we're ready to go in a number of different directions. Plant populations have gone up, and I don't see why they won't continue to increase. We test at higher densities today. Fertilizer price could change farmers' decision on plant population.

Looking at corn on their Slater, Iowa, plots, Ben Hable of Syngenta and Chris Zinselmeier, the company's program leader, say they expect water efficiency to be a key component in boosting yield.

We have to be ready to go however farmers go. The farmer will figure how to get the best return on investment," Hable says.

The company continues to combine basic genetic work with genetically modified traits. Syngenta plans to launch a drought-tolerant corn­—the company prefers to call it "water optimization"—in 2011. Interestingly, it is not a transgenic trait but was found through native plant breeding, says Chris Zinselmeier, program leader for Syngenta Seeds.

"It's about water-use efficiency, generating more grain yield over different environments. If it reduces irrigation requirements, it should save energy inputs. We're thinking more broadly about water-use efficiency than drought tolerance," Zinselmeier says.

"We are looking for single genes or a combination of genes behind the native trait and for ways to bring them together so we can stack them within the hybrid. Grain yield under limited water conditions is a complex trait," he says.

Hable thinks the industry is just at the start of some potentially huge breakthroughs, thanks to scientists mapping the corn genome.

"Now we're gene rich, but we're assigning functions to those genes. It's a huge investment to assign those functions. It's a number game. How much material can you screen? How much progeny can you look at? How quickly can you do it? It changes overnight. It's going to accelerate and is accelerating already," Hable says.

At Iowa State University in Ames, Roger Elmore, Iowa Extension corn specialist, and Kendall Lamkey, chair of the agronomy department, say they're skeptical that the national corn yield will hit 300 bu. per acre by 2030 or increase 40% during the next decade.

They believe the average corn yield will increase at about the same rate it has in the past 10 years, putting it a little more than 200 bu. per acre by 2030.

"You could argue that we've picked the low apples on the tree already. How much earlier can we plant? We've gained a lot of yield by planting earlier. We can't control weeds and insects better than we're already doing. Most biotech traits have been protective, not for yield," Elmore says.

"It's an interesting argument about the yield, and it's all technology-based. The companies are only focused on one-fourth of the problem. It's fourfold: genetics, soils, management and weather. Agronomy is the interaction of all that," Lamkey explains.

"I find it interesting that as a country we've invested only in genetics. There's no investment in soils or management. That's why I think we won't get to 300 bu. per acre by 2030.

"You're talking about getting a rate-of-yield increase more than threefold. It's going to take more than molecular models and transgenes. No one is doing the research to get us to 300 bu.," Lamkey says. "Plus, you've got to put a sustainability wrapper around all this. The best soils in the world, the Corn Belt soils, are rapidly degrading at a rate that will have an impact unless we do something about that. If you got the top agronomists at a table and asked what limits yield, you wouldn't get a single answer. The emphasis on genetics lulls the public into a sense that everything is going to be all right."

Ken Ferrie, Farm Journal Field Agronomist, says the price of corn will be key to a yield push. "Is it 300-bu. at $2 per bushel or $7 per bushel? At $2 corn, a lot of marginal areas will not raise corn, which would help the national average. If it's $7, you start throwing in a lot of acres that never were in corn, and that's a bigger hill to climb. The learning curve is steep on those acres," Ferrie says.

You can e-mail Charles Johnson at

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