Union of Concerned Scientists: GE crops have NOT decreased yields

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The Union of Concerned Scientists, a progressive political science-activism organization, just released a report Tuesday on GE crops and yield. Written by Doug Gurian-Sherman, the new report is titled Failure to Yield. You can read the whole thing here, and the press release is here.

Of course, as the title of the report suggests, Gurian-Sherman did not explicitly conclude that GE crops have not decreased yields – he concluded that GE crops did not increase yields significantly. At face value, it seems like a reasonable conclusion, one that follows from my understanding of the GE traits that are currently grown: mostly herbicide tolerance and pest resistance. In the case of herbicide tolerance in corn and soy, Gurian-Sherman concluded that the trait did not increase yields, while progress in plant breeding continues to do so.

Also fairly reasonable-sounding is his conclusion that pest resistance from Bt crops did increase yield slightly – increasing yield by about 3-4% since its introduction in 1996. I have yet to delve into how he makes these determinations, you can expect another post from me on this report down the road. (Especially since Gurian-Sherman has been saying elsewhere that Bt contributed 4-5% – which is it?) But as far as the press release is concerned, it is leaving out crucial information – Bt corn has allowed (slightly) higher yields to be grown with fewer pesticides. That’s the point of a pest resistance trait such as Bt.

A very important point worth mentioning is that Gurian-Sherman only studied two traits in two crops – three combinations in total. This doesn’t support the sweeping conclusion that is made about the future contributions of this technology to yields. In fact, to be exact, the reports findings would lead to the conclusion that herbicide tolerance and Bt traits in corn and soy don’t contribute significantly to yields overall.

And this paragraph in the press release appears to be false:

The biotechnology industry has been promising better yields since the mid-1990s, but Failure to Yield documents that the industry has been carrying out gene field trials to increase yields for 20 years without significant results.

At GMO Pundit, David Tribe saved an article about a yield-increasing biotechnology trait that increases soybean yields by 6 to 7 percent, tested in 56 field environments. This hasn’t been published in a peer-reviewed journal as far as I know, but Gurian-Sherman should have been aware of this – it was published over three months ago.

At the Council for Biotechnology Information’s new BIO convention blog, they posted a few reactions to Failure to Yield. One, by Wayne Parrot at the University of Georgia:

“The report is at odds with the results from the experience of farmers around the world. At the very least, the current biotech crops are preventing yield losses to pests. In the end, it is not just about yield- it is about the ability to practice no-till farming (thus saving fossil fuels and preventing soil erosion); it is about the ability to use less insecticides, it is about the ability to make farming easier and more profitable and sustainable. So even if there were no yield advantage, there are plenty of other reasons to use biotech crops.”

Anyway, take a look at the report and let me know what you think. When I have a little time I’ll give it a thorough read. But it will be interesting to see what people find in the analysis.

To bring it back to the title of this post – I would like to mention how many anti-GE activists claim that genetic engineering has decreased yields. Those same organizations are now clamoring with joy, but if they accept the conclusions of this paper, they must also accept that genetic engineering did not decrease yields. If the UCS found any hint of that in the literature, you know that would be the headline!

Follow Karl Haro von Mogel:
Karl earned his Ph.D. in Plant Breeding and Plant Genetics at UW-Madison, with a minor in Life Science Communication. His dissertation was on both the genetics of sweet corn and plant genetics outreach. He recently moved back to his home state of California. His favorite produce might just be squash.