Science - April 13, 2010

Crop biodiversity going up, not down

The decrease in biodiversity in the natural environment must lead to a decrease in the genetic variety of breeds among plant breeding companies. That would seem logical, wouldn't it? But it isn't the case. The genetic diversity in new breeds at plant breeding firms has increased slightly over the past few decades, after a fall in the nineteen sixties.

This is reported by researchers at the Dutch Centre for Genetic Resources (CGN) in the April edition of Theoretical and Applied Genetics. Mark van de Wouw of the CGN evaluated 44 publications in which the genetic diversity of crop varieties was studied with the help of genetic marker technology. 'If there are twenty varieties of a genetic marker instead of two, then of course there is a greater diversity. But if the overwhelming majority of the cultivars all have the same marker, it means the diversity is low. We analysed a number of studies this way in a meta-analysis.'
Van de Wouw was amazed to find that the genetic variety in the crops has increased over the past forty years, after a drop of six percent in the nineteen sixties. 'Many biologists believe that genetic erosion is getting steadily worse, and that genetic variety in crops is decreasing with it. Only that idea has never been verified.'
Van de Wouw has two explanations for the way the genetic variety of the cultivars has held up. New techniques make it easier for plant breeders to introduce genes from other varieties into their species. And secondly, since many gene banks were set up in the nineteen sixties, more genetic material has become available to the plant breeding sector.