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Expert explains issues with altering makeup of crops
(Thursday, Oct. 30, 2003 -- CropChoice news) -- Monica Riordan, The News Record: "We need to ask ourselves: is this an innocuous thing, should we be doing this?" said Allison A Snow, speaking about the possible effects of transgenic crops on ecosystems.
Monday afternoon Martha Benedict Tuttle and UC's Department of Biological Sciences presented the Dr. Harris M. Benedict Memorial Lecture in Room 502 Rieveschl Hall. Benedict was the former chair of the Biology and Botany departments at UC.
"An Ecologist's View of Genetically Engineered Crops" was presented to a standing-room-only audience of faculty, students, relatives of Benedict and community members.
Transgenic crops have genes spliced, or inserted, into their genetic make-up from an organism outside the plant kingdom. Snow, a professor of evolution, ecology and organismal Biology at The Ohio State University and president-elect of the Botanical Society of America, offered two sides of the biotechnology debate.
"How are we going to control pests and increase yields and how can biotechnology contribute to this?" said Snow.
Consider Bt corn, Bt cotton and Bt sunflowers; all plants that have had a gene inserted into their genetic code from the bacterial-organism bacillus thuringiensis. The Bt gene, known as a transgene, acts as a built-in pesticide for lepidopteron, a type of caterpillar, eliminating the need for spraying pesticides.
"There are no boundaries for where transgenes may end up," said Snow. "What's going to happen when these transgenes move around?"
Snow is currently studying the Bt gene in sunflowers. There is significant cross-pollination that goes on between crop sunflowers and their wild cousins when the plants are within 1000 meters of each other, she said.
In a controlled experiment, "weedy" wild sunflowers containing the Bt gene produced up to 55 percent more seeds per plant, because of decreased insect damage, when compared with unmodified plants.
"The Bt gene works very, very well in the crop and in the weed," said Snow.
Snow's study found if Bt sunflowers were grown commercially, a likely consequence would be an increased abundance of its wild cousin. The Bt gene could also potentially kill non-target butterfly and moth larvae that feed on wild sunflowers.
There are many transgenic crops being tested for possible commercial applications that have wild, "weedy" relatives. Canola, wheat, rice, squash and maize are examples of crops that could pass a transgene onto their wild relatives or to a field that is supposed to be free of genetically-engineered organisms.
Maize, or corn, produces a lot of pollen making the risk for genetic drift especially high. Snow discussed the case of Oaxaca in southern Mexico.
"People have been growing native varieties for centuries," said Snow. "Yet transgenes are being found there."
The transgenes may have been introduced in the form of food aid from the United States. Native people could have planted a few grains of our transgenic corn resulting in cross-pollination, Snow said.
"Psychologically it makes a huge difference," said Snow. "Scientifically it may not make much difference."
This statement refers to the controversy that surrounds genetically engineered crops. On the one side are the five or six multi-national companies introducing these technologies that have enormous potentials for economic and ecological benefits. On the other, there are activists who see the risks of gene flow to unintended organisms as potentially devastating, and therefore too risky.
"I'm an ecologist and I worry if all the companies are asking the right questions," said Snow.
Snow offered many examples of the possible benefits of genetically modifying crops. There are some genes that decrease the need for chemical pesticides, fungicides and fertilizers, all significant polluters of the environment and risks to human health.
The "Round-Up Ready" soybean, which represent 80 percent of all soybeans grown in the United States, encourages no-till weed control that leads to more organic matter and less topsoil loss.
Some transgenic crops have the potential for increased nutrition value, others the ability to grow in extremely poor soils and harsh conditions.
Snow countered that these same technologies could encourage pesticide resistant insects and herbicide resistant weeds, or effect non-target organisms in unintended and irreversible ways.
Snow advocated proceeding with transgenic crops, but only with careful research about the effects on native ecology.
Source: http://www.nr.uc.edu/read.asp?ID=13875
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Dangerous Liaisons?
With the advent of genetic engineering, "designer" crops might interbreed with natural populations. Could such romances lead to the evolution of "superweeds", as some have suggested? But haven't crops had sex with wild plants in the past? Has such gene swapping occurred without consequences? And if consequences have indeed occurred, what lessons can be gleaned for engineered crops?
In Dangerous Liaisons? Norman Ellstrand examines these and other questions. He begins with basic information about the natural hybridization process. He then describes what we now know about hybridization between the world's most important crops—such as wheat, rice, maize, and soybeans—and their wild relatives. Such hybridization, Ellstrand explains, is not rare, and has occasionally had a substantial impact. In some cases, the result was problematic weeds. In others, crop genes have diluted natural diversity to the point that wild populations of certain rare species were absorbed into the gene pool of the more common crop, essentially bringing the wild species to the brink of extinction.
Ellstrand concludes with a look to the future. Will engineered crops pose a greater threat than traditional crops? If so, can gene flow and hybridization be managed to control the escape of engineered genes? This book will appeal to academics, policy makers, students, and all with an interest in environmental issues.
"In the stormy sea of debate over genetically modified organisms, Ellstrand's book is a safe and fascinating harbor of science-based opinion on cultivated plants in their larger gene pools. A visionary scientist and an ethical public servant, Ellstrand sets the quality standards for all who will follow." -- Gary Paul Nabhan, Director, Center for Sustainable Environments, author of Coming Home to Eat: The Pleasures and Politics of Local Foods
"A well-written, objective account of the prevalence and roles of hybridization in plants, focusing on the relationships between crops and their wild and weedy relatives. This book is important reading for those concerned with the development of agriculture in the future, and the standards that ought to be applied when new strains of crops are developed. Norman Ellstrand has provided us with the best account of this important field." -- Peter H. Raven, Director, Missouri Botanical Garden
"Buckle up for a rollicking ride through the world of plant sex. Norman Ellstrand, scientific investigator, is on the trail of a little-noticed phenomenon, the migration of plant genes across the boundaries of farmers' fields. He provides a comprehensive and even-tempered look at an old phenomenon that has suddenly acquired new relevance in this era of genetically engineered crops. An essential guide to a fascinating and often startling topic." -- Daniel Charles, author of Lords of the Harvest: Biotech, Big Money, and the Future of Food
"This book brings science to bear on a controversial issue—the possible escape of engineered genes into wild species. Although Ellstrand's discussion is nuanced and sophisticated, his friendly and informal writing style makes it palatable. Ellstrand has produced the rare book that does not compromise the science yet remains a pleasure to read."--Loren Rieseberg, Indiana University
"With insight, originality, and extraordinary scholarship, Norman Ellstrand brings together classical and current knowledge about crop evolution, crop breeding, and evolutionary ecology, weaving historical and ultra-contemporary themes into a single, comprehensive treatment. This book is a masterpiece that will be highly influential and widely cited." -- Allison Snow, Ohio State University
Norman C. Ellstrand is a professor of genetics and director of the Biotechnology Impacts Center at the University of California, Riverside. | |
