Across the globe, plant breeders seek genetically modified plants to increase crop yield, build up disease resistance and delay crop ripening. Meanwhile, national governments and activist groups question the safety of these crops.
Greenpeace, an environmental activist group, has led numerous protests calling for a ban on G.M. corn. France and Greece have ignored possible sanctions from the E.U. by actively speaking against the cultivation of G.M. corn, papaya and eggplant.
Genetic modification involves transferring a gene of interest from one species into another. In some cases, plant breeders insert these genes into a naturally occurring bacterium and then into the target plant. The final G.M. product contains only the transported gene and not the bacterium as a whole.
Prof. Leon Kochian, crop and soil sciences and director of the United States Department of Agriculture’s plant, soil and nutrition laboratory, has been working on identifying a gene in sorghum — a subtropical crop used as animal feed. The gene allows the plant to survive in high-aluminum soil, an otherwise lethal condition for most plants. When Kochian identified the gene, he introduced it into the DNA of various plants to study which modified plants successfully withstood aluminum contamination.
According to Kochian, aluminum-tolerant plants can potentially allow people in resource-poor areas of the world to introduce new crops that previously could not be supported. This, he added, could benefit the millions of people who suffer from malnutrition.
“It [has] been estimated that anywhere between 30 and 50 percent of the land in the world is acidic,” Kochian said, citing that the soil’s acidity is responsible for dissolving aluminum — a major soil contaminant. “Plant breeders have been taking advantage of genetic variations for 50 years to breed for more aluminum-tolerant crops,” he added.
However, since many crops lack the genetic variation necessary to breed for aluminum tolerance, plant breeders genetically modify plants to suit their interests; one case is corn genetically-engineered to increase ethanol yield.
Over the past decade, farmers have increasingly produced a variety of corn containing a disease-resistant gene from Bacillus thuringiensis (Bt), a soil bacterium that produces protein that kills harmful target insects. However, because the protein is consumed along with the corn, activist groups argue that this modification poses a threat to humans. Still, Kochian argued that people do not realize that G.M. technology reduces the use of chemicals that have negative impacts on the environment.
Contrary to Kochian’s study, Profs. John Losey and Linda Rayor, entomology, and Maureen Carter grad found in a study conducted in 1999 that about half of monarch butterfly caterpillars fed from milkweed dusted with Bt-corn pollen died, suggesting that Bt may not be the ultimate solution. On the other hand, all butterflies fed with regular milkweed survived. The researchers also found that, when blown miles away onto traditional corn farms, Bt-corn pollen can fertilize the unmodified corn, thereby modifying the harvested crop. More so, the more Bt-corn planted, the higher the risk of normal corn being transformed into Bt-corn, they argued. In addition, other studies have suggested that G.M. corn pollen harms non-target insects.
Still, the FDA released results of numerous follow-up studies that argued that there is not enough G.M. pollen to cause significant harm to caterpillars.
Like corn, Bt-eggplant — a G.M. variety partly developed at Cornell in 2007— has been a subject of controversy in India. As its possible approval looms over the horizon, some have called for more research on Bt-eggplants. According to the University, the team of researchers showed that this variety of eggplant reduced pesticide use by about 30 percent and nearly doubled the yield.
Does Bt-eggplant pose a health risk? The USDA says no; however, not everyone is willing to accept that. According to Greenpeace-funded French Scientist Giles-Eric Seralini, Bt-plants pose health risks and “cannot be considered as safe as [their] non-G.M. counterpart[s].” Still, the Indian government remained unconvinced, and plans to approve the production of Bt-eggplants.
“I think that a lot of the debate around genetic engineering isn’t really grounded in a whole lot of science.” Sarah Davidson PhD ’08 said, adding that the public needs to be cautious when making claims about potential environmental impacts of G.M. food.