GM crop contamination may be product of sloppy handling, not cross-pollination

By Emily Kirkland, mongabay.com
January 04, 2011

A recent study has suggested that sloppy seed handling may be partially responsible for the presence of genetically modified plants in conventional fields. For years, farmers have been reporting that fields planted with traditional seeds sometimes yield GM plants. Many scientists believe that this pattern is due to cross-pollination: insects carry pollen from neighboring GM fields into conventional fields, resulting in some GM plants. But a new paper just published in PLoS One argues that the effect of cross-pollination is actually quite small. In the fields tested by the researchers, fewer than 1 percent of all conventional cotton plants produced genetically modified Bt seed as a result of insect cross-pollination.

The researchers argue that in fact, the main problem is that GM seeds are often mistakenly mixed with regular seeds. Sometimes, this happens before the seeds are even sold. When the researchers tested one bag of supposedly “conventional” seed, for instance, they found that it actually contained 28% GM seed. There was also human error during the planting process: in one field, a row designated as conventional was accidentally sown with GM seed. Because the GM and regular seeds look identical, these types of problems are difficult to detect.

There have been reports of similar mix-ups in the past. In September, for instance, a small number of potato plants corresponding to a unapproved, experimental GM strain were found growing in Swedish fields. The problem was later attributed to an error at the facility that produced the potato seeds, where two potato varieties were accidentally mixed.

Contamination by GM crops can carry serious consequences. If GM crops are found on an organic farm, for instance, the organic certification may be taken away–regardless of whether or not the contamination was intentional. Many farmers also use stands of conventional crops on the border of GM fields in an attempt to prevent pest resistance. GM contamination of regular seed can undermine that strategy.

Environmentalists and other advocacy groups have been demanding more regulation and oversight for GM crops for years. Still, in many countries, enthusiasm for GM remains undimmed. Two weeks ago, for instance, Brazilian regulators approved three new types of GM crops for production in Brazil—two new varieties of corn and an additional variety of cotton.

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By Emily Kirkland, mongabay.com (January 04, 2011).

GM crop contamination may be product of sloppy handling, not cross-pollination.