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.