Right now, there is some truth to this criticism. None of the GM crops widely grown around the world are designed to boost yields directly — but that could be about to change.

A team of researchers announced today that they have genetically modified wheat to increase the efficiency of photosynthesis. When the plants are grown in glasshouses, the change boosts yields by 15 to 20 per cent. Now they are applying to the UK government for permission to carry out field trials.

The field tests are essential to confirm the alteration works, says team member Malcolm Hawkesford of Rothamsted Research in Harpenden, UK, where the trials will begin in spring 2017 if they get the go-ahead.

Next stage: field trials

“It works when you grow it in a pot in a greenhouse,” Hawkesford says. “But in the real environment, you often don’t see the same response.”


If the plants produce anything like a 15 per cent increase in yield in field tests, it will be a spectacular result. “It’s an extremely beneficial trait,” says Hawkesford.

In the UK, wheat yields have plateaued at around 8 tonnes per hectare. Getting more wheat from the same area of land would have massive environmental benefits – freeing up land to put aside for wildlife or to capture carbon, for example.

What’s more, the modification helps plants takes advantage of the rising levels of carbon dioxide in the atmosphere. “In higher levels of CO 2 , this works even better,” Hawkesford says.

The team say they have made other genetic alterations that also boost yields in greenhouse tests, though they are not yet ready to divulge details. Several of these yield-boosting modifications could be “stacked” together in a single strain to create superplants.

So how does it work?

Plants make the food we eat by adding carbon dioxide from the atmosphere to a five-carbon molecule. In plants like wheat and tobacco, the supply of these five-carbon molecules often runs short, limiting the efficiency of photosynthesis.

So Hawkesford and colleagues, including Christine Raines of the University of Essex and Elizabete Carmo-Silva of Lancaster University, have added extra copies of an enzyme called SBPase, to increase the supply of the five-carbon molecule.

For the field tests, they have created strains of a spring wheat called Cadenza with anywhere from one to six extra copies of the gene for SBPase.

Cadenza is an old wheat variety that is no longer grown commercially. If the trial succeeds, newer strains of wheat would need to be modified to create commercial products – but that’s a long way off, Hawkesford stresses.

Soaking up more carbon

Crops with extra copies of this enzyme should perform even better in the future. In so-called C3 plants like wheat, the availability of CO 2 often limits growth. So where conditions are suitable, the rising levels of CO 2 in the atmosphere are boosting the growth of C3 plants.

But ever higher CO 2 does not mean ever higher growth – experiments show the fertilisation effect tails off because plants are unable to take advantage of ever more plentiful CO 2 . One reason is that plants grab CO 2 molecules from the atmosphere faster than they can make the five-carbon molecules to attach them.

The only way the world is going to be able to limit warming to 2 °C is by sucking vast amounts of carbon from the atmosphere, using technology that does not yet exist. What is clear is that it will require vast amounts of land – so we desperately need ways to grow more food on less land. GM superwheat would certainly help.