Crop Scientists Seek a New Revolution

The tools that more than doubled world grain harvests since 1960 have lost their edge, and productivity increases--rises in cereal yields per hectare--are slipping. Bold efforts to bioengineer crop plants seem the only hope for a new surge in harvests, which will be needed to keep pace with a projected 40% increase in global demand for rice, wheat, and maize by 2020. But even if those innovations pan out--and plant breeders are far from sanguine about the prospects--researchers fear that farmers may not have enough water to grow the new crops or may be forced to use so much fertilizer on marginal land that they will poison ecosystems and permanently damage soils.