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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    No sooner had the deal been made than the critics of agricultural biotechnology erupted. "A rip-off of the public trust," grumbled the Rural Advancement Foundation International, an advocacy group based in Winnipeg, Canada. "Asian farmers get (unproved) genetically modified rice, and AstraZeneca gets the 'gold.'" Potrykus was dismayed by such negative reaction. "It would be irresponsible," he exclaimed, "not to say immoral, not to use biotechnology to try to solve this problem!" But such expressions of good intentions would not be enough to allay his opponents' fears.

    Weighing the Perils
    Beneath the hyperbolic talk of Frankenfoods and Superweeds, even proponents of agricultural biotechnology agree, lie a number of real concerns. To begin with, all foods, including the transgenic foods created through genetic engineering, are potential sources of allergens. That's because the transferred genes contain instructions for making proteins, and not all proteins are equal. Some--those in peanuts, for example--are well known for causing allergic reactions. To many, the possibility that golden rice might cause such a problem seems farfetched, but it nonetheless needs to be considered.

    Then there is the problem of "genetic pollution," as opponents of biotechnology term it. Pollen grains from such wind-pollinated plants as corn and canola, for instance, are carried far and wide. To farmers, this mainly poses a nuisance. Transgenic canola grown in one field, for example, can very easily pollinate nontransgenic plants grown in the next. Indeed this is the reason behind the furor that recently erupted in Europe when it was discovered that canola seeds from Canada--unwittingly planted by farmers in England, France, Germany and Sweden--contained transgenic contaminants.

    The continuing flap over Bt corn and cotton--now grown not only in the U.S. but also in Argentina and China--has provided more fodder for debate. Bt stands for a common soil bacteria, Bacillus thuringiensis, different strains of which produce toxins that target specific insects. By transferring to corn and cotton the bacterial gene responsible for making this toxin, Monsanto and other companies have produced crops that are resistant to the European corn borer and the cotton bollworm. An immediate concern, raised by a number of ecologists, is whether or not widespread planting of these crops will spur the development of resistance to Bt among crop pests. That would be unfortunate, they point out, because Bt is a safe and effective natural insecticide that is popular with organic farmers.

    Even more worrisome are ecological concerns. In 1999 Cornell University entomologist John Losey performed a provocative, "seat-of-the-pants" laboratory experiment. He dusted Bt corn pollen on plants populated by monarch-butterfly caterpillars. Many of the caterpillars died. Could what happened in Losey's laboratory happen in cornfields across the Midwest? Were these lovely butterflies, already under pressure owing to human encroachment on their Mexican wintering grounds, about to face a new threat from high-tech farmers in the north?

    The upshot: despite studies pro and con--and countless save-the-monarch protests acted out by children dressed in butterfly costumes--a conclusive answer to this question has yet to come. Losey himself is not yet convinced that Bt corn poses a grave danger to North America's monarch-butterfly population, but he does think the issue deserves attention. And others agree. "I'm not anti biotechnology per se," says biologist Rebecca Goldberg, a senior scientist with the Environmental Defense Fund, "but I would like to have a tougher regulatory regime. These crops should be subject to more careful screening before they are released."

    Are there more potential pitfalls? There are. Among other things, there is the possibility that as transgenes in pollen drift, they will fertilize wild plants, and weeds will emerge that are hardier and even more difficult to control. No one knows how common the exchange of genes between domestic plants and their wild relatives really is, but Margaret Mellon, director of the Union of Concerned Scientists' agriculture and biotechnology program, is certainly not alone in thinking that it's high time we find out. Says she: "People should be responding to these concerns with experiments, not assurances."

    And that is beginning to happen, although--contrary to expectations--the reports coming in are not necessarily that scary. For three years now, University of Arizona entomologist Bruce Tabashnik has been monitoring fields of Bt cotton that farmers have planted in his state. And in this instance at least, he says, "the environmental risks seem minimal, and the benefits seem great." First of all, cotton is self-pollinated rather than wind-pollinated, so that the spread of the Bt gene is of less concern. And because the Bt gene is so effective, he notes, Arizona farmers have reduced their use of chemical insecticides 75%. So far, the pink bollworm population has not rebounded, indicating that the feared resistance to Bt has not yet developed.

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