The new green revolution that will feed the world

Today, around 3.5 billion people will sit down to a meal of something and rice. The “something” will depend on whether it’s Jamaica, Shanghai or Kerala, but rice is one of the world’s constants. It is a staple food for nearly half the globe and provides a fifth of all the calories humanity consumes. It is hard to overstate its importance. And that importance is growing: the world’s population, which swept past seven billion last year, is projected to reach nine billion by 2050. How are we going to feed all those new mouths?

People have been predicting that the global population will outrace our ability to feed it for 200 years. In the 1960s and 1970s, gloomy bestsellers like Paul Ehrlich’s The Population Bomb foretold billions of deaths from starvation, and the collapse of civilisation: “the battle to feed humanity is over”, Ehrlich said.

But the Green Revolution, led by Norman Borlaug, won the battle that Ehrlich said was lost. Using techniques borrowed from Gregor Mendel, the father of genetics, he bred a new form of wheat. Its shorter stems broke less easily and wasted less energy in growth; it was disease-resistant and yielded more food. Suddenly, the amount of food available from a hectare of land rocketed. Borlaug’s innovation is credited with saving a billion lives – and the nation of India. No wonder he won a Nobel Peace Prize for his work.

But now, half a century later, we need more. Bill Gates, in his foundation’s annual newsletter, is warning that the crop yields are no longer keeping pace with population growth, and that we need to “prioritise agricultural innovation” if we are to avoid Ehrlich’s predictions. Prof Sophien Kamoun of the Sainsbury Laboratory, a leading plant science research centre near Norwich, agrees: “Right now there are one billion people hungry around the world. In the last 11 years we added a billion people to the planet – that’s the equivalent of China. And we’re going to add another two Chinas in the next 40 years. We need a new Green Revolution.”

His team is one of a number worldwide who are working on precisely that. The Sainsbury Laboratory is a key collaborator on MutMap – a new technique for improving and accelerating the process of breeding which, researchers hope, will build on the Green Revolution. It uses genome sequencing and analysis to show which genes in rice have important effects – stem height, seed size and so on. It’s not conventional transgenic modification, adding a new gene to the plant from another source. It relies on ordinary mutations and selective breeding, the methods used for generations, but with the added power of gene sequencing.

“I’m not saying that MutMap is going to lead to the second Green Revolution,” says Prof Kamoun. “But there is a lot going on now in genomics-enabled breeding, of which MutMap is a part. And all these technologies together, as well as transgenic genetic modification, will lead to a new revolution.”

The technique has already reaped results. In a paper published this month in Nature Biotechnology, the Sainsbury team and Japanese colleagues describe a new strain of semi-dwarf rice, similar to Borlaug’s wheat. Yet even as their research was on going on, a catastrophic earthquake and tsunami hit Japan, swamping and “salt-spoiling” 20,000 hectares of arable land. “Our Japanese collaborators started screening for salt-tolerant mutants,” says Prof Kamoun, “and they already have resistance – it’s really promising.”

It’s not just the growing population that these new technologies can help with. All natural varieties of rice have been bred over hundreds of years in relatively stable climates. If, as expected, the climate starts to change rapidly, those local varieties will become less well adapted, and yields will drop. But MutMap and other genomic breeding techniques may be able to help mitigate that. “There are all kinds of traits that can be looked at: temperature tolerance, drought tolerance. If the climate does change, the rice can be tweaked to adapt to it,” says Prof Karmoun.

The advantage of rice – and the reason that the researchers have chosen it – is that it has a relatively small genome. Other crops, like maize, have larger, more complex genomes, meaning that it is hard to sequence them and find the right genes to tinker with. But the speed of progress is startling. The cost of analysing a stretch of DNA is dropping precipitously, in a way analogous to “Moore’s Law” of computing, which says that the cost of a given amount of processor power halves every 18 months. In a few years’ time, MutMap and its equivalents could mean that the Green Revolution becomes a permanent one.

Source : The Telegraph