2003 2ND PLACE

One day we’ll rute the departure of Daniel, Ebeneezer and the District Nurse

William McDowall
2nd place winner of the 20-28 category

The Daniel's Defiance runner bean, which once graced allotments across the country, may soon join dodos and dinosaurs on nature's rejects' pile. While most acknowledge that losing an obscure vegetable variety would be a shame, few of us are likely to lose much sleep over it. Runner beans, however delightfully named, simply can't match pandas or polar bears for conservation appeal.

We should be more concerned. Agricultural biodiversity is an important part of our national heritage, explains Bob Sherman from the Henry Doubleday Research Association's Heritage Seed Library - and not simply because the Daniel's Defiance might taste nice. The erosion of crop genetic diversity at all levels (diversity of species, of varieties, and even genetic diversity within a crop variety) may threaten the future of farming.

In nature, diversity provides insurance - any child can tell you that eggs are safer in a variety of baskets. The Irish potato crop in the mid-19th century was devastated because of the genetic uniformity of the plants. Potatoes are propagated clonally rather than sexually, and most of Ireland was planted to a narrow gene pool. In a diverse system, some of the plants might have been resistant to potato blight, and disaster could have been averted.

Diversity is not just about insurance within the field - it's about securing our crops for future generations. As gardeners can attest, plants have to fight to stay alive (this can border on the obsessive - my mother frequently claims to be kept awake at night by the sound of slugs munching on her larkspurs). Species alive today are here because their ancestors were the best, the toughest, the fittest. Traditional crop varieties are the result of both natural selection and generations of farmers' breeding. They are adapted to the conditions in which they have evolved - desert plants tolerate drought, those from high-level latitudes shrug off frost.

The genes that plants contain make up a library of solutions to the problems that those ecosystems pose to survival. This is our genetic heritage, and one of humanity's most valuable yet endangered resources. Crop breeders need nature's library to develop new varieties which incorporate the best traits from traditional crops.

But the library has been slated for redevelopment, and the bulldozers have moved in. Traditional varieties are being replaced by their modern, higher yielding counterparts all over the world. This is fine for food production, but if the unique genetic strategies contained in those traditional varieties are lost for ever, it is very bad news for the long term future of agriculture. Genetically uniform, high-yielding varieties all succumb to pests or disease eventually, and if yields are to be sustained we need new sources of resistance.

One answer to this problem of genetic erosion is to collect the seeds of as many varieties as possible and store them for future use. This takes up little space, and is a relatively cheap and efficient way of preventing the loss of genetic material. The problem is that seeds can't do much evolving in a drawer, and with evolution put on ice, the varieties we store today will not develop resistance to the pests of tomorrow.

Seed banks need backup, and this comes from in situ conversation, in which diverse varieties continue to be grown in the habitats in which they evolved. At the Heritage Seed Library, Bob Sherman and colleagues not only maintain a seed bank, they also distribute hundreds of seeds for gardeners to grow in allotments and vegetable plots around Britain - keeping the turnips on their toes, as well as providing gardeners with unusual and tasty vegetables.

Of course, runner beans and onions aren't the only plants that we depend on. Major crops, such as wheat and potatoes, all have centres of diversity far from Britain, and it is there that diversity must be maintained, but the principle is the same worldwide. It would be more than a shame to lose this rich genetic heritage, so spare a thought for the Ebeneezer onion and the District Nurse climbing bean - their genes might one day save the crop.

The author, 24, is finishing his masters thes s at Leeds and came second in the older category of the BASF/Daily Telegraph science writing competition. He received his at the British Association's festival in Salford