A wheat crop grows at a farm near Parkes
A wheat crop grows at a farm near ParkesREUTERS/Daniel Munoz

In a major blow to genetic modification of crops, a variety of wheat developed in the UK to repel pests has failed in field trials.

The variety engineered to produce an odour that repels aphids, failed in the field test after it was successfully tested in the lab, proving a wide gap between lab and commercial application of the process.

The results of the trial held by Rothamsted Research in 2012-2013 was published this week in the journal Scientific Reports. Among the many hypothesis for the failure one was that the aphids became used to the chemical deterrent.

The genes producing anti-insect pheromone (E)-beta-farnesene was introduced into the plant to develop aphid resilient crops in order to reduce the amount of pesticides required by plants.

This smell is found naturally in plants like peppermint and it disperses aphids.

Aphids - such as greenfly and blackfly - damage plants by sucking nutrients from their sap and can also introduce plant viruses.

Dr Toby Bruce, first author of the study and senior chemical ecologist at Rothamsted Research told BBC: "In science we never expect to get confirmation of every hypothesis. Often it is the negative results and unexpected surprises that end up making big advances - penicillin was discovered by accident, for example."

The trial was subject of protests by anti-GM campaigners like GM Freeze in 2012. They were quick to note the outcome was further evidence of the "folly" of investing in GM technology.

The project cost £732,000 ($1.1m) with an additional £444,000 spent on fencing to protect the trial site.

Liz O'Neill, director of GM Freeze, said: "The waste of over £1m of public funding on a trial confirms the simple fact that when GM tries to outwit nature, nature adapts in response."

The technology is believed to hold much potential in growing more crops under reduced pesticide input. However, safety concerns over allergies, gene contamination, etc have seen few nations adopt the technology.

GM crops

Genetically modified crops are being grown commercially since 1996. The land coverage of GM crops has increased over 100 fold from 1.7 million hectares in 1996 to around 175.2 million hectares worldwide in 2013.

But nearly 90% of GM crops are grown in five countries alone — the United States, Brazil, Argentina, India and Canada, with the US contributing 40% of the produce.

According to the World Health Organization (WHO) GM crops have not been shown to pose a greater health risk to humans than conventionally bred crops. But WHO has classified glyphosate, a herbicide sprayed on many GM crops, as "probably carcinogenic to humans".

In the EU, each individual GMO must receive approval before it can be sold as seed or used in food and feed. Any food and animal feed containing more than 0.9% of GMOs has to be labeled.

UK has regulations to ensure the safety of environmental release of genetically modified organisms for research trials. It is pushing for controls on the commercial use of GM products to what the government says "encourage innovation and growth".

The top three GM crops by coverage are soybeans (52% of total GM area in 2009), maize (31%), and cotton (12%).

All commercial GM crops today are genetically altered mostly for herbicide tolerance and insect resistance.