To Tropical Crops

Every hectare of paddy fields in Asia provides enough rice to feed 27 people. Fifty years from now, according to some projections, each hectare will have to cater for 43. Converting more land to paddy is not an option, since suitable plots are already in short supply. In fact, in many of the continent's most fertile river basins, urban sprawl is consuming growing quantities of prime rice-farming land. Moreover, global warming is likely to make farmers' lives increasingly difficult, by causing more frequent droughts in some places and worse flooding in others. Scientists at the International Rice Research Institute (IRRI) doubt it is possible to improve productivity as much as is needed through better farming practices or the adoption of new strains derived from conventional cross-breeding. Instead, they aim to improve rice yields by 50% using modern genetic techniques.

The Consultative Group on International Agricultural Research (CGIAR), a network of research institutes of which IRRI is a member, unveiled a series of schemes intended to protect crop yields against the ill effects of global warming. Many involve genetic engineering—which is generally embraced by farmers in poor countries even if some Western consumers turn their noses up at it. Some, though, only use genetics to identify useful genes. For example, IRRI's scientists have found a gene that allows an Indian rice strain to survive total immersion for several weeks, and have cross-bred it into a strain favoured by farmers in flood-prone Bangladesh. In trials, the new plant produced as much rice as the original under normal conditions, but over twice as much after prolonged flooding. This trait could increase the world's rice harvest dramatically, since flooding damages some 20m hectares (50m acres) of rice each year out of a total crop of 150m hectares.

By far the most ambitious project on CGIAR's list, though, involves transforming the way in which rice photosynthesises. That will require some serious genetic restructuring.