Grains Of Hope

TIME Diagram by Joe Lertola
Source: Dr. Peret Beyer, Center for Applied Biosciences, University of Freiburg
How to Make Golden Rice
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Assessing the Promise
Are the critics of agricultural biotechnology right? Is biotech's promise nothing more than overblown corporate hype? The papaya growers in Hawaii's Puna district clamor to disagree. In 1992 a wildfire epidemic of papaya ringspot virus threatened to destroy the state's papaya industry; by 1994, nearly half the state's papaya acreage had been infected, their owners forced to seek outside employment. But then help arrived, in the form of a virus-resistant transgenic papaya developed by Cornell University plant pathologist Dennis Gonsalves.

In 1995 a team of scientists set up a field trial of two transgenic lines--UH SunUP and UH Rainbow--and by 1996, the verdict had been rendered. As everyone could see, the nontransgenic plants in the field trial were a stunted mess, and the transgenic plants were healthy. In 1998, after negotiations with four patent holders, the papaya growers switched en masse to the transgenic seeds and reclaimed their orchards. "Consumer acceptance has been great," reports Rusty Perry, who runs a papaya farm near Puna. "We've found that customers are more concerned with how the fruits look and taste than with whether they are transgenic or not."

Viral diseases, along with insect infestations, are a major cause of crop loss in Africa, observes Kenyan plant scientist Florence Wambugu. African sweet-potato fields, for example, yield only 2.4 tons per acre, vs. more than double that in the rest of the world. Soon Wambugu hopes to start raising those yields by introducing a transgenic sweet potato that is resistant to the feathery mottle virus. There really is no other option, explains Wambugu, who currently directs the International Service for the Acquisition of Agri-biotech Applications in Nairobi. "You can't control the virus in the field, and you can't breed in resistance through conventional means."

To Wambugu, the flap in the U.S. and Europe over genetically engineered crops seems almost ludicrous. In Africa, she notes, nearly half the fruit and vegetable harvest is lost because it rots on the way to market. "If we had a transgenic banana that ripened more slowly," she says, "we could have 40% more bananas than now." Wambugu also dreams of getting access to herbicide-resistant crops. Says she: "We could liberate so many people if our crops were resistant to herbicides that we could then spray on the surrounding weeds. Weeding enslaves Africans; it keeps children from school."

In Wambugu's view, there are more benefits to be derived from agricultural biotechnology in Africa than practically anywhere else on the planet--and this may be so. Among the genetic-engineering projects funded by the Rockefeller Foundation is one aimed at controlling striga, a weed that parasitizes the roots of African corn plants. At present there is little farmers can do about striga infestation, so tightly intertwined are the weed's roots with the roots of the corn plants it targets. But scientists have come to understand the source of the problem: corn roots exude chemicals that attract striga. So it may prove possible to identify the genes that are responsible and turn them off.

The widespread perception that agricultural biotechnology is intrinsically inimical to the environment perplexes the Rockefeller Foundation's Conway, who views genetic engineering as an important tool for achieving what he has termed a "doubly green revolution." If the technology can marshal a plant's natural defenses against weeds and viruses, if it can induce crops to flourish with minimal application of chemical fertilizers, if it can make dryland agriculture more productive without straining local water supplies, then what's wrong with it?

Of course, these particular breakthroughs have not happened yet. But as the genomes of major crops are ever more finely mapped, and as the tools for transferring genes become ever more precise, the possibility for tinkering with complex biochemical pathways can be expected to expand rapidly. As Potrykus sees it, there is no question that agricultural biotechnology can be harnessed for the good of humankind. The only question is whether there is the collective will to do so. And the answer may well emerge as the people of the world weigh the future of golden rice.