If there was ever a good year for drought-tolerant corn research, this year was it. In July, more of the United States suffered moderate or severe drought than at any other time in the 12-year history of the U.S. Drought Monitor. The effects were certainly felt across the Corn Belt, especially in Indiana, which had its driest year since 1988. However, seed developers are working on hybrids to help growers deal with these conditions.
Harvest data from this year are not yet available, but as Jeff Schussler, senior research manager, maize stress, DuPont Pioneer, pointed out, the Corn Belt’s considerable amount of consistent drought stress this season gave breeders the opportunity to see significant differences among hybrids.
Wayne Fithian, product lead, technical traits Syngenta, is based in Nebraska and has observed a significant amount of mid- to late-vegetation drought across much of the Corn Belt this year. He saw height differences between Syngenta’s water-optimized hybrids containing Agrisure Artesian technology and other hybrids at both knee-high and waist-high stages, and particularly good performance in a 101-day maturity hybrid containing Agrisure Artesian.
Three hybrids containing the technology were commercialized in the western Corn Belt last year; they yielded up to 15% better than hybrids without Agrisure Artesian under moderate to severe drought stress, Fithian said. In the absence of drought, Syngenta observed no difference among hybrids up to a 4% improvement in yield with the hybrids containing the technology.
The company also is developing water-optimized hybrids using a genetically modified trait. Syngenta expects these hybrids will be available sometime after 2015.
Six additional hybrids containing Agrisure Artesian are in commercial trials across the Corn Belt this year.
DuPont Pioneer also saw differentiation last year when approximately 8,000 on-farm trials showed that its Optimum Aquamax hybrids yielded an average 7% better than grower-selected checks in water-limiting environments. Pioneer introduced eight of these hybrids in 2011, and added 17 more in 2012.
Ranging in maturity from 96 to 116 days, the Optimum Aquamax hybrids have been developed using molecular breeding techniques to quickly identify genes responsible for improving yields and other traits, such as drought tolerance. This first class of hybrids has been developed using five hybrid platforms, Schussler said.
The leaves of these hybrids are slower to roll than the leaves of other hybrids during drought stress, which means they continue to intercept sunlight needed for photosynthesis, Schussler said. He added that DuPont Pioneer breeders have been able to select for earlier flowering. During drought stress, flowering three to four days earlier can help corn plants beat the heat—producing the necessary silks, setting pollen and beginning kernel development.
Monsanto, in cooperation with BASF, also is testing drought-tolerant hybrids this year, with Genuity DroughtGard hybrids being evaluated in a large-scale, on-farm trial program called Ground Breakers.
Although harvest data were not yet available, the development and kernel count of these hybrids looked promising, notes Mark Edge, Monsanto. These hybrids are part of a system featuring a biotech drought-tolerance trait, germplasm selected for performance in dry conditions.
Pending regulatory approvals, Monsanto will test and commercialize Genuity DroughtGard hybrids next year.
No silver bullet
Hybrids that perform better under drought stress and that can perform as well or better than other hybrids under non-drought conditions are certainly of interest to growers. But these seed company representatives agree they aren’t a silver bullet. They may not be the right choice for every field.
“It’s important that farmers still take into account the overall agronomic package, including maturity, stalk quality and disease resistances,” Syngenta’s Fithian says.