Radiation used to develop varieties of plants - geneticist

Consumers seem frightened of genetically engineered foods but indifferent to foods altered by genetic mutation. Plant specialists regularly use radiation and mutagenic chemicals to develop new plant varieties, according to a plant geneticist from Teagasc.

Most beers on the market are made using a barley variety produced in 1965 by x-ray induced mutation, said Dr Beant Ahloowalia of Teagasc, the agriculture and food development authority. The technique involved using exposure to powerful chemicals or radiation to cause unpredictable breaks in a plant's genetic code which may then recombine to produce new traits.

The technique differs from genetic engineering which involves inserting genes, often from another species, into a plant or animal in the expectation that the recipient will take on the new trait given by the gene. Mutation is far less targeted, but it also could produce new traits. The public seemed largely unaware of its use, Dr Ahloowalia told delegates yesterday at the 11th International Congress on Radiation Research in UCD.

"You can mutate or you can put in a transgene, but the public acceptance of mutation is much better than with transgenes," he said. `In the absence of the acceptance of GM foods, the process of mute genesis allows the development of novel varieties." Unlike GM technology, mutation technology is freely available to any researcher via UN agencies.

More than 2,000 important crops and ornamental plants have been developed using mutation, including new rice varieties, short stem grains, tomato, pepper and potato varieties.

Another significant crop modified by mutation is the sunflower. Mutated varieties produced oil which was better at helping to reduce cholesterol in the diet. There was also the celebrated mutation of a Japanese pear variety in an orchard adjacent to a nuclear reactor, he said. A fungus struck the orchard and the crop was lost except for one tree near the reactor, which had a healthy crop. It was found to be a radiation induced mutation which conferred resistance to the pathogen.

"Most mutants are degenerate and worthless," said Dr Alan Cas sells of UCC. These were quickly discarded but promising varieties were tested to ensure they were safe for consumption. "What the consumer wants is reassurance."

Mutation was useful for correcting a characteristic defect or for introducing novel characteristics, he said. The mutant was usually compared to the source plant when assessing new or altered traits, for example the plant's response to pathogens.

If plant held promise it was put through a battery of high-technology tests which scanned its new genetic make-up. This "data mining" allows researchers to test unexpected changes in the genetic code. Plants could be selected for disease or drought resistance after irradiation as a way to develop resistant varieties, said Dr S. Moham Jain of the University of Helsinki.

He described inoculating 400 strawberry plants with a fungus; 20 were found to have developed resistance to the fungus. They were also found to have acquired resistance to drought.