For the past two decades, promises of crop improvement have been the domain of genetically modified plants: mostly, crops supplemented with bacterial genes to resist pests or weedkillers like Roundup. More than 85 percent of U.S. corn, soy or cotton grown contains such genes.
But there is more than one way to transform a plant.
Using advanced biotechnology, long hidden in the background and only now starting to pay dividends, scientists are changing crops without tapping foreign genes -- and often without the regulatory oversight that is given to GM crops.
Many of these crops use latent effects of genes squirreled away in discarded seed varieties to create breeds that at first glance seem artificial. There is corn so infused with vitamin A precursors that it practically glows orange, rice that can survive more than two weeks of flooded conditions, and wheat that resists the advance of devastating aphids.
Such specialized crops are possible because researchers are mastering the science of breeding. Using techniques collectively known as molecular breeding, geneticists have started to return results in a variety of plants, said Ed Buckler, a plant geneticist at Cornell University who recently helped sequence the corn genome.
"We know that old-fashioned good breeding works," Buckler said. "And a lot of that is an intelligent numbers game" based on genetic theories elaborated by Gregor Mendel more than a century ago. Molecular breeding, he added, "is now a way to do that much faster."
Increasingly affordable with improved technology, molecular breeding is becoming the mode of business in the crop world, said Bonnie McClafferty, development head at HarvestPlus, a nonprofit funded by the Bill & Melinda Gates Foundation that supports molecular breeding research into improving plant nutrition in Africa and Asia.
"People don't understand that we're not working with Gregor Mendel anymore," McClafferty said. "The science is advancing, and there's a whole variety of tools to use."
In fact, molecular breeding is only the start of a bewildering diversity of biotech approaches to crop development that defy the conventional notion of splicing foreign genes into plants. This next generation could shake up what has become a stalled debate -- call it the Roundup Ready stalemate -- by introducing GM crops that, for example, use only their species' native genes or have the expression of their own genes silenced.
While the techniques draw from the same pool of knowledge, and travel together in scientific circles, many environmental groups do not oppose molecular breeding, while stridently critiquing current GM crops, according to Marco Contiero, the European biotech policy director for the environmental group Greenpeace.
"Genetic engineering is just a part of modern biotechnology," Contiero said. "We are against this specific application. We are not against marker-assisted selection."
Most scientists believe that molecular breeding and advanced genetic modification will eventually form a powerful tandem, said David Baulcombe, a professor of botany at the University of Cambridge and the chairman of a recent report issued by the United Kingdom's Royal Society on the future of agriculture.
"Within genetic modification, you've got to remember there's a whole bunch of technologies," Baulcombe said. "There's GM where you move plants' genes around. GM where you use artificial genes to silence gene expression. And then there's the technology that is out in the field now in which bacterial genes have been moved into the crop."
For thousands of years, crop breeding remained much the same: Farmers crossbred plants with desirable traits like high yield, as often as not reproducing those traits in offspring. Mendel clarified the situation, but conventional breeding practices today, though stirred by developments like the green revolution's hybrids, would remain roughly familiar to farmers of a century ago.
Molecular breeding has, to some extent, overturned this framework, even prompting some scientists to call for new, post-Mendel theories of breeding. The techniques rely in principle on the increasing inventory of genes that have been identified as influencing, if to a limited degree, traits in plants. For some genetically simple crops, like rice, these clusters of genes have strong effects, while the genes of more complex grains like corn and wheat have been more difficult to pin down.