“Let’s be clear. As of this year [2008], there are no commercialized GM crops that inherently increase yield. Similarly, there are no GM crops on the market that were engineered to resist drought, reduce fertilizer pollution or save soil. Not one.” – Dr Doug Gurian-Sherman, Genetic engineering — a crop of hyperbole. The San Diego Union Tribune, 18 June 2008.

Claims of higher yields from GM crops pop up constantly in the media. It seems to be an example of a misleading claim that is repeated so often that people frequently fail to question it. Yet in the case of the most widely grown GM crop, GM soybeans, there has been evidence of consistently lower yields for over a decade. Controlled comparative field trials of GM/non-GM soya suggest that 50% of the drop in yield may be due to the genetic disruption caused by the GM transformation process. 

A US Department of Agriculture report confirms the questionable yield performance of GM crops, saying, "GE crops available for commercial use do not increase the yield potential of a variety. In fact, yield may even decrease.... Perhaps the biggest issue raised by these results is how to explain the rapid adoption of GE crops when farm financial impacts appear to be mixed or even negative."

Monsanto released its second generation RR2 Yield GM soybeans in 2009, claiming that they would deliver higher yields. By June 2010, however, reports had emerged that yields were again disappointing and that the state of West Virginia had launched a probe into Monsanto for consumer fraud for false advertising claims.

Conventional non-GM approaches, in contrast, have consistently been improving crop yields for decades and continue to do so. Such successes, in contrast with the often mythical claims for high-yielding GM crops, tend to go largely unsung. 

Here are a few examples of what non-GM approaches have been achieving. What would the GM lobby give for success stories like these?

Beans

High yielding, multi-disease resistant, non-GM bean success in Rwanda (February 2010)
An excellent example of the success of traditional plant breeding practices - multi-disease resistant, very high yielding, and apparently freely distributed without Intellectual Property restrictions.

Cassava

High-yielding disease-resistant super-cassava for Africa (September 2010)

Cotton

Non-pesticide, non-GM cotton pest management success in India (June 2007)
A relatively low-tech approach to managing pests promises to help hundreds of thousands of cotton farmers across Asia raise yields and reduce environmental contamination.

Cowpea

Cowpeas bred for extra-early maturity, high protein and high yield potential with resistance to major diseases and aphids, as well as high levels of tolerance to heat and drought, for tropical and subtropical countries (April 2013)

Maize

Orange maize improves yields and nutrition for families in Zambia (April 2013)

Australian non-GM high-yield maize lines to target Asian markets (April 2011)

Zambia: better non-GM maize harvests (June 2005)

Although drought-prone Zambia is still facing many problems, huge improvements have been reported in its maize harvests - its main staple crop. A report from Inter Press Service notes, "... production changed dramatically after President Levy Mwanawasa took over from Frederick Chiluba in 2001.... [He] promoted innovations like mixed farming and conservation farming. Mwanawasa rejected GM maize and encouraged the growing of non-GM maize, resulting in bumper harvests for the past three consecutive years." When the Zambian government rejected GM maize in 2002, there were calls from the US Ambassador to the FAO for its leaders to be tried "for the highest crimes against humanity in the highest courts of the world."

Oil palms

A new variety of oil palm developed using traditional breeding is projected to increase crude palm oil yields by up to double current levels (May 2017)

Studying genes may lead to higher yield, sustainable oil palms (April 2011)

Rice

“Green Super Rice” is saline-tolerant, drought-tolerant, disease-resistant, and high-yielding without the use of fertilisers and pesticides (November 2014)

New generation high-yield rice varieties unveiled for Africa (May 2013)

"Extended life" rice could quadruple yields, cut costs (September 2011)

"Super-rice" – bred for high yield, disease-resistance, etc. (January 2011)

Soy

High-yielding, soybean cyst nematodes-resistant non-GM soybeans (July 2007) 
Soybean growers now have more options when selecting soybean varieties that have high yield potential and the ability to stave off soybean cyst nematodes - SCN, a tiny worm that infests the soil in many fields in Iowa and the rest of the Midwest of the United States and which steals soybean yields.

Sweet potato

Smallholder farmers in Mozambique are growing nutritious and lucrative varieties of orange-fleshed sweet potato, which are are high vitamin, flood-resistant and produce double normal yields (December 2014)

Tomato

US scientists develop high-yielding tomato (March 2010)
New hybrid tomato plants are super producers capable of generating more and much sweeter fruit without genetic engineering.

Wheat, potatoes, rice and other crops

Hybrid crops without the GM (August 2013)
British researchers are leading a global project to track down and store wild relatives of common crops - to help breed hybrids with higher yields that could be resistant to the effects of climate change.