Science and technology.Salt-tolerant rice.Nuclear-powered crops.Physics meets biology in a project to breed better strains of rice.THOSE who turn their noses up at "genetically modified" food seldom seem to consider that all crops are genetically modified.The difference between a wild plant and one that serves some human end is a lot of selective breeding-the picking and combining over the years of mutations that result in bigger seeds, tastier fruit or whatever else is required.Nor, these days, are those mutations there by accident. They are, rather, deliberately induced, usually by exposing seeds to radiation.And that is exactly what Tomoko Abe and her colleagues at the Riken Nishina Centre for Accelerator-Based Science in Saitama, outside Tokyo, are doing with rice.The difference is that Dr Abe is not using namby-pamby X-rays and gamma rays to mutate her crop, as is the way in most other countries.Instead she is sticking them in a particle accelerator and bombarding them with heavy ions-large atoms that have been stripped down to their nuclei by the removal of their electrons.This produces between ten and 100 times as many mutations as the traditional method, and thus increases the chances of blundering across some useful ones.Dr Abe's plan is to use these mutations to create salt-tolerant rice.She has tried to do that several times in the past, but the result did not taste very nice.