The Union of Concerned Scientists has released a report attacking big farma’s claims that genetically modified crops produce a higher yield per cultivated acre than traditional crops.

The report [pdf] examines academic reports of crop yields over a 20-year period, including 13 years of real-world commercial results in the US. Author Doug Gurian-Sherman attributes most yield gains in most crops to technique, not genes:

Overall, corn and soybean yields have risen substantially over the last 15 years, but largely not as result of the GE traits. Most of the gains are due to traditional breeding or improvement of other agricultural practices.

Gurian-Sherman also distinguishes between intrinsic yield, which is an idealized measure, and operational, or real-world yield. Genetic engineering only improved operational yields for corn modified with genes from Bacillus thuringiensis, a bacteria which helps the corn resist certain pests, he writes.

An industry group has responded with its own release claiming that “marker-assisted breeding has nearly doubled the rate of yield gain when compared to traditional breeding alone” and pointing out that a growing number of farmers are adopting genetically modified strains of crops.

Gurian-Sherman concedes that farmers may find certain modified crops easier to work with, but that this does not directly translate into an improved yield or a wider benefit to society.

Related in Nature News: Germany banned a breed of genetically-modified corn yesterday, joining a handful of other European countries in contradiction of EU law.

Photo: Seabamirum on Flickr