Letter: Refined crop danger

Sir: An important argument about genetically modified foods is being ignored: the danger to the future of the genetically modified crops themselves.

Genetically refined strains of crops are very susceptible to strong blights or pests. If you "refine" or "reduce" the gene structure of a plant to its most productive, or if you take out the ancient wild or unrefined or natural genes, you reduce the plant's ability to withstand an attack by a blight or pest. With pesticide use over many years, strong, resistant pests or blights have developed. Genetically "narrow" or "weak" plants have been attacked and even wiped out by strong pests or blights.

This occurred in some notable cases in recent years, once when a whole year's wheat crop in Kansas was wiped out by a strong blight and more importantly when a genetically modified rice crop in Southeast Asia was attacked and destroyed. Both were only saved for future generations by seeking out wild natural strains and "breeding" the wild strength back into the gene structure. In the case of the wheat, a major search occurred for a compatible wild strain and the only one was finally located in a valley in India. The valley was planned to be flooded for a reservoir the next year.

Organic farming may well be dearer in the short term but considerably safer in the long term.

MICHAEL WISE

Lytchett Minster, Dorset