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. Her latest effort was stimulated by the flooding with seawater of almost 24,000 hectares of farmland by the tsunami which followed an earthquake in March last year. Salt-tolerant rice would, though, be of much wider use than just restoring the paddies of Miyagi prefecture and its neighbours, the worst-affected part of the country, to full productivity. About a third of the world's rice paddies have salt problems, and yields in such briny fields may be half what they would be if the water in them were fresh. To induce the mutations, Dr Abe bombarded germinating seeds with carbon ions for 30 seconds. She then planted them in fields in Miyagi. Of 600 seeds that have undergone this treatment, 250 thrived and themselves produced healthy seeds. The next stage of the project, to be carried out this month, is to take 50 grains from each of the successful plants and repeat the process with them. The resulting specimens will then be sorted and the best (ie, those that have flourished in the saline soils of Miyagi's paddies) selected for crossbreeding, in order to concentrate desirable mutations into reproducible lines of plants. The result, Dr Abe hopes, will be a viable salt-tolerant strain that is ready for market within four years. With luck, this time, it will be a tasty one as well.