가뭄저항성 옥수수 효과가 긍정적인 초기 결과를 보여주다

In the midst of the nation's worst drought in 50 years, two of the world's largest agricultural companies are testing corn that is bred and genetically engineered to withstand low rainfall levels.

Monsanto's DroughtGard hybrid corn -- the first-ever hybrid genetically engineered for drought tolerance -- was planted this spring in initial field trials. Sowed amid sufficient rain and optimism for a record-breaking crop yield, the company has encountered a close to worst-case scenario to test its product.

In addition, DuPont Pioneer's hybrid AQUAmax corn -- developed using advanced breeding techniques rather than biotechnology -- debuted last year with five different versions. This year, the company is launching six more with drought tolerance traits combined with pest resistance and other high-yielding attributes.

But the drought ripping through the Midwest is persistent and widespread. Despite positive feedback from farmers, the companies admit that cutting-edge technology can only go so far.

"We know there's a limit; we know you cannot grow corn without water," said Jeff Schussler, senior research manager in maize stress product development for Dupont Pioneer. "There's nothing magical about these hybrids."

The western Plains states typically experience drought conditions nearly every year, but this year's arid weather is more widespread and is hitting the heart of corn country.

"I don't think there will ever be a solution for this severe of a drought," said Mark Edge, DroughtGard marketing lead at Monsanto. Instead, the company seeks to reduce losses.

"It's really about managing risk," he said. "It's still corn, and it still needs water."

Nevertheless, both companies are pleased with early anecdotal results of their work. About 250 farmers on close to 100,000 acres across the western Great Plains planted DroughtGard in the spring.

Among those is Clay Scott, a corn grower in western Kansas who volunteered to grow the engineered corn as part of Monsanto's field trials.

"We're starting to see some real winners in the plots," said Scott, whose land is located in a region in extreme to exceptional drought, according to the U.S. Drought Monitor. "I'm excited about it."

Last year, yields of AQUAmax corn were observed 8,000 times, with 680 of those considered to be in a stressed environment. AQUAmax yields were 7 percent higher in the stressed environments compared to conventional hybrids.

Questionable gains to society
Drought resistance comes through the plant's ability not lose its hydration through respiration. The hybrids are bred or engineered to reduce the size of the plant's stomata, pores on the surface that regulate the flow of water inside and outside the plant. In addition, genes to improve and increase kernel development or combat pests increase yield despite the lack of available water.

In turn, the agriculture companies expect to produce corn plants with less leaf rolling, indicating that the crop is managing water stress better. AQUAmax corn growers have reported full and uniform corn silk, said Schussler, which facilitates successful pollination and forms an ear full of kernels.

Scott, the Kansas grower who draws his groundwater from the strained Ogallala Aquifer, expects to yield 200 bushels per acre for his irrigated corn and 100 bushels for dryland corn. If conditions continue, the National Corn Growers Association anticipates a 131-bushel national average, far below the 167 bushels per acre anticipated in the spring.

The Union of Concerned Scientists, a group advocating for the environment and scientific integrity, has been particularly critical of agricultural companies' claims, targeting the largest of them all: Monsanto.

The group released a report in June finding that Monsanto's drought-tolerant corn will only offer modest protection for drought tolerance. While it may help individual farmers recoup yield losses in drought conditions, it would not increase food production to sustain a climate-stressed world, the report says (ClimateWire, June 5).

DroughtGard would only increase productivity by less than 1 percent per year, said the report's author, Doug Gurian-Sherman, a senior scientist in the group's Food and Environment Program.

In the face of criticism, big agricultural companies have repeatedly said that advanced genetic manipulation -- through biotechnology or advanced breeding technology -- is no bull's-eye solution but is simply a tool to better manage arid conditions.

"We've always told farmers they need to have realistic expectations," Schussler said.

In a climate-stressed world, farmers will need to adapt with new management practices, and Edge hopes using drought-resistant hybrids will re-emphasize the importance of water conservation.

"We can make progress," he said. "But it's one step at a time."

Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC. www.eenews.net, 202-628-6500