Dryland corn in the desert? Not quite. But the next generation of drought-tolerant corn hybrids will do something almost as amazing—optimize water usage in the Corn Belt and on marginal acres currently not suitable for corn.

Most years, Iowa, Minnesota, Nebraska and Illinois, for example, receive adequate rainfall to produce a good corn crop. It’s the timing of the rainfall that often limits yield.

Tallying instances of total crop failure and lost yield potential due to crop stress in normal years, it’s estimated that drought causes global crop losses in excess of $8 billion annually. The impact of drought will likely increase, based on predictive models used to study the effects of climate changes.

Seed companies have always sought to select corn hybrids for drought tolerance and yield stability. The recent decade of advancements in biotechnology and use of molecular markers to track specific genes in corn has accelerated drought tolerance programs.

The three largest seed companies—Monsanto Company, Pioneer Hi-Bred International Inc. and Syngenta—all say we can expect high-yielding corn with drought-specific traits early in the next decade. The traits will come from a combination of conventional breeding of native corn genetics and genetically engineered traits that are specifically targeted to help corn yield more under heat and drought stress.

Here’s a quick update on the technological advancements made by these three seed companies looking to bring drought traits to the market.

Monsanto

Monsanto recently reported that it is the industry’s first company to advance a drought project into the regulatory and commercial phase. The company’s second-generation drought-tolerant corn advanced to Phase 2, and first-generation drought-tolerant corn advanced to Phase 3—just a few years from commercialization.

Monsanto’s John Headrick, chief of development for drought-tolerant corn, says there could be broad applicability for the new drought-tolerant traits. “When people think of drought, they tend to think of the Great Plains and the western corn-growing regions of Kansas and Nebraska, but there may be utility in the heart of the Corn Belt, as well,” he says. “A drought trait can provide better yield stability for existing corn acres. Also, we may see continued expansion of corn acres, and these traits may enable corn growth where only sorghum and wheat grow now.”

Headrick points to a broad stable of drought-trait candidates. “Some genes come from simple microbes like bacteria. Others might come from other plants. We have multiple sources of genes. We screen them in model crops very quickly to get a good look at all genes that are available to us. And we get those very quickly into corn and screen them in the field.”

Different drought traits may be needed for different parts of the country. “The pipeline is developing a portfolio of traits with applications to different growers,” says Jacqueline Heard, Monsanto’s project leader for drought-tolerant corn. “The Great Plains grower has different needs for irrigated crops versus the person in the central Corn Belt looking for protection from drought.”
     
Pioneer

In 2007, Pioneer bolstered its longstanding drought-tolerance program by announcing a research collaboration with biotech company Evogene Ltd. Under the agreement, Pioneer has exclusive rights to several genes discovered by Evogene to improve drought stress traits in corn and soybeans. 

“Drought has an enormous impact on crop productivity and quality, as well as cost of production. It’s the one agronomic pressure that negatively affects growers in every country around the world every year,” says William Niebur, vice president of DuPont Crop

Genetics research and development. “We look forward to creatively combining our technologies to develop superior products that use water more efficiently, leading to greater productivity, profitability and sustainability of agricultural systems.”

The candidate genes were discovered by Evogene’s data-mining tool called ATHLETE (Agro Traits Harvest Leads Technology). The technology rapidly sorts through the tens of thousands of genes that have been cataloged in plants and has been used to discover stress-tolerant genes in tomatoes and is being used by Monsanto to identify nitrogen efficiency genes. Pioneer is now in the process of evaluating its licensed genes for drought stress in its elite corn and soybean germplasm.

Jeff Schussler, a research scientist with Pioneer’s drought program, estimates that in any given year, one-third of U.S. corn acres experience yield-reducing drought stress.

“Weeds and insects used to be the primary yield robbers, but with herbicide-tolerant and insect-resistant traits well established, now drought is the No. 1 target,” Schussler says. “Our drought candidates come from a three-pronged approach that includes conventional breeding, molecular breeding and transgenic programs that might move novel genes into corn. We’ve learned that drought tolerance, like yield, is more likely the result of many genes interacting in the plant.”

Syngenta

Syngenta’s Water Optimization Technology is on track to hit the market by 2011. Syngenta scientists are working on a combination of biotechnology and native corn traits to achieve their objectives. Research trials are showing yield improvements of more than 10% in corn plants that are under drought stress, compared with the same hybrid in drought conditions without the trait. This means corn hybrids that yielded 130 bu. per acre under drought stress conditions in 2007 could yield a minimum of 13 more bushels per acre. Assuming successful development and domestic and export approvals, the water optimization hybrids should be available in all of Syngenta’s branded seed corn, including Garst, Golden Harvest and NK.

Wayne Fithian, the corn product business lead for Syngenta, says the new hybrids will help farmers harvest higher corn yields in areas that tend to be dry at some point in the season.

“We also think we can expand corn into areas that are now limited to a wheat–fallow rotation,” Fithian says.  “With a wheat–corn–fallow rotation, farmers can pick up another crop every six years, and they can clean up some of the problems wheat has with weeds and disease.” 

Fithian says Syngenta is looking at several genes to improve yields with less water. “One of our most promising traits reduces potential for kernel abortion when the plant is under drought stress,” Fithian says. “By the 4th of July, it can get drier and drier. But the corn plant wants 0.3" of water a day—1" every three or four days. This is a crucial time, shortly after pollination, blister stage and early milk, for realizing optimum yield potential. If the plant senses it is running out of water it aborts tip kernels. Our new gene helps prevent kernel abortion by switching off corn’s natural tendency to slow nutrient flow to developing kernels during drought stress.”

Fithian says trials of Syngenta’s water optimization hybrids are growing in South America and will be planted in 2008 at research locations in North America. That puts the company on track to market its water optimization hybrids early in the next decade.

By that time, Monsanto, Pioneer and Syngenta are all likely to have drought traits in the field. Climate change, El Niño, or not, we can expect the race between seed companies to heat up as each vies to claim a slice of the lucrative drought-trait market. 

Thirsty Corn

Any region of the country can experience periods of heat and drought stress. Elwynn Taylor, a climatologist at Iowa State University, says in 2007 the Midwest experienced pockets of extreme dryness, as well as widespread areas of excessive moisture. If this is due to the El Niño/La Niña cycle, long-term climate change or other cyclical climate activity is a matter of hypothesis and speculation. What is known is that erratic weather will tend to swing and spike widely within the larger weather trend.

Erratic weather is typified by the simultaneous occurrence of drought and excess precipitation, often in the same locality during a single season. Temperature extremes are also typical. Three or more conditions, independently or in combination, result in abnormally erratic weather in the Midwest. Some years ago it became apparent that the primary manifestation of global warming was increasingly erratic weather. Year-by-year variations in the impact of erratic conditions are attributed to the 19-year climate cycle and to La Niña.

Exactly how much rainfall is needed to grow 1 bu. of corn will vary by geography and soil type. David Nielsen, a research agronomist with the USDA-Agricultural Research Service in Akron, Colo., offers one example. “Using a water-to-yield relationship generated in Nebraska, we would need about 25.8" of water to grow 200 bu. per acre of corn. Water use efficiency of corn grain production generally improves as we move east and north of Colorado.”