Human Error Responsible For GM Crop Escapes

Quit blaming the bees. Careless handling of seeds may be the key reason for the unintended spread of genetically modified (GM) crops, a study has found.

The discovery challenges the widespread belief that the main source of GM contamination is the transfer of pollen by bees from GM crops to non-GM counterparts in neighbouring fields. Human error during seed production and handling is the more likely culprit, say the researchers.

Stands of non-GM crop plants are currently planted near or within fields of modified crops to provide refuges for pests. This technique helps prevent the pests developing resistance to the pesticides used on GM crops. But human error could undermine this widely used strategy, the paper says.

Shannon Heuberger, an entomologist at the University of Arizona, and her colleagues measured the gene flow — the movement of genes between different populations that occurs when a plant from one population fertilises a plant from the other — in Bt (Bacillus thuringiensis) cotton, the widely planted GM crop, in 15 fields in Arizona.

They found that gene flow via the transmission of pollen by bees was rare. Fewer than one per cent of seeds produced by ordinary cotton plants contained genes from Bt cotton that had been transmitted in this way.

But poor seed-sorting resulted in some seed bags intended for planting in non-GM fields containing as much as 20 percent GM seed. One non-GM field was found to have a large number of GM plants due to human error in planting.

Read the full story in The Guardian.