sealPurdue News

February 2001

Double crops, cut the acreage by 2010, predicts scientist

WEST LAFAYETTE, Ind. – Imagine two crops of corn or soybeans each growing season. Plant in March, harvest in July. Plant another crop, harvest in November.

What to most farmers would sound like pure foolishness could become a reality within a decade, according to a Purdue University plant scientist.

Ray Bressan, professor of horticulture and director of Purdue University's Center for Plant Environmental Stress Physiology, says scientists have learned as much in the past three years as in the previous 100 about how crops and other plants withstand environmental stresses.

The result of this bloom of knowledge is that scientists will soon be able to create new crop varieties that can withstand and even thrive through environmental stresses such as frost, heat and drought.

Although doubling crop production won't necessarily cut the amount of farm land in half, thanks to the need to feed an ever-increasing world population, the need for crop land could be significantly reduced. An added bonus would be that by planting two crops per growing season each year, U.S. farmers could take much of the nation's 320 million acres of farm land out of production, creating millions of new acres of wildlife habitat.

"A couple of years ago I wouldn't have predicted this," Bressan says. "But within a decade it will be possible to have crops that can withstand the stresses of early spring and late fall."

Drought, heat, frost, salty soil and nutrient-deficient soil are some of the types of environmental stresses that crops must endure. Farmers' worries about these stresses are as old as praying for rain, and for good reason: These environmental stresses cause massive crop-yield losses each year – more, in fact, than losses from insects and weeds.

Bressan says scientists have always assumed that the ability to thrive through stress was a genetically complex trait, and so researchers assumed that it would be a waste of time to try to create such crop varieties. But recent discoveries in plant genetics have turned that view upside down.

"What we're finding is that there are a lot of genes involved, but the good news is that there are less than a couple of dozen – a manageable number of genes – that have significant effect on stress tolerance. This gives us great hope that we can understand and improve these crops within the next few years."

Some crops, such as rice and cotton, don't tolerate environmental stresses well. Both crops require large amounts of water. Sorghum, on the other hand, is a crop that does tolerate drought well. Scientists hope to identify the genes in crops that can handle stress and use that information to improve the genetics of the crops that don't handle stress well.

"A common misunderstanding about this type of research is that we want to enable farmers to grow plants in exotic environments like deserts. We don't have that as a goal," Bressan says. "The real goals are to improve productivity on the land we're already using and to avoid having to use poor land. If we don't do this type of research, we're going to be forced to use more land for agriculture to feed the world's population."

A small mustard plant called Arabidopsis – which could be considered the lab mouse of the plant world – is leading scientists to their understanding of how plants tolerate stress. Scientists selected this plant as the experimental model because it is easy to work with, but because all plants are genetically similar, researchers can apply what they learn about Arabidopsis to other plants.

To determine the function of each of the 25,000 genes in Arabidopsis, researchers pick one gene and find a plant that has a mutation in that gene. They then grow plants with that mutation to observe the effect the mutation has on the plant's physiology. Researchers at Purdue's Center for Plant Environmental Stress and Physiology have created more than 300,000 plants each with a mutant gene, and scientists at other institutions have created hundreds of thousands of additional mutant plants.

"For all practical purposes the genome is saturated; there has been a mutation for every gene," Bressan says. "The genetics of Arabidopsis is 80 percent known, and by the end of this year it will be completely known."

Bressan says the rapidly accumulating knowledge about the biology of plants will cause equally rapid changes in agriculture. "We'll soon be able to produce more crops with less pesticides, less fuel, less fertilizer, fewer trips over the field. We'll produce more with less," he says. "Everyone agrees that agriculture is degrading the environment, but biotechnology has the potential to reverse that."

Bressan adds that as an environmentalist, he thinks other environmentalists are missing the point of much biotechnology research. "It's kind of a shame that the environmental political groups are not embracing biotechnology," he says. "It's true that biotechnology should be properly regulated and cautiously applied. Scientists are not opposed to regulations – nobody wants to do crazy things. But here the environmentalists are missing the potential to advance their cause, which is really everyone's cause."

Source: Ray Bressan, (765) 494-1336;

Writer: Steve Tally, (765) 494-9809;

Purdue News Service: (765) 494-2096;

Related Web sites:
Center for Plant Environmental Stress Physiology

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