June 10 (Reuters) - In the crop world, corn is a Ferrari, rice is a VW Beetle.
For decades, scientists have been tweaking rice to achieve small increases in yield every year. But over the past decade or so, those increases have reached a plateau while demand for rice keeps growing.
Scientists say they are limited to what they can do with rice unless they totally re-engineer its genetic structure.
The main way to do this is boosting photosynthesis in rice, the scientific equivalent of bolting on a turbo-charger.
A global project is trying to do just that, with the aim of genetically enhancing rice to double yields and become as productive as corn.
In nature, some plants are much more efficient in the way they grow because they have a genetically superior form of photosynthesis, which involves using the Sun’s energy to convert carbon dioxide sucked into the leaves and creating sugars and other organic compounds for the plant to grow.
Corn, sugar and sorghum possess this more efficient C4 photosynthesis in their leaves. Rice and wheat have the more primitive C3 pathway.
In a hot climate, corn yields can be 50 percent more than rice, have double the water-use efficiency and use about 40 percent less nitrogen. Achieving these benchmarks in rice would revolutionise the production — and food security — of a staple on which about a third of humanity relies.
The project, led by the International Rice Research Institute in the Philippines, and involving a team of scientists around the globe, is trying to crack the genetic code that will supercharge photosynthesis in rice.
The C4 crops have a different leaf structure that concentrates the CO2 soaked up from the air. They also have a much more productive process to convert CO2 into sugars that fuel faster plant growth.
Scientists at IRRI, Australia’s state-backed research arm the CSIRO and at Cambridge University are working on the genetic toolbox needed to create this more efficient leaf structure in rice.
The project, funded by the Bill and Melinda Gates Foundation, involves looking at which genes are involved in leaf development and the “switches” that control those genes.
Changing the order of these switches might create a more efficient leaf in rice one day. IRRI estimates it could take 20 years before scientists roll out C4 rice to farmers.
After that, C4 wheat could be next.
Reporting by David Fogarty; editing by Bill Tarrant