Insurance in a Freezer: Seed Banks

In a mountain on an island in the Arctic Ocean, a vault holds duplicate samples of seeds from collections around the world. It is the best known of more than a thousand facilities that store the seeds of crop plants, and its purpose is insurance. If war, flood or neglect destroys a national collection, the vault can send back what was lost. Visitors expecting a doomsday bunker are usually surprised by how ordinary the work is: sealed foil packets, labelled shelves and a great deal of paperwork. The case for such collections rests on a fact that is easily overlooked. Over the last century, farmers in most countries have abandoned the many local varieties their grandparents grew in favour of a handful of high-yielding ones. The change fed millions of people, but it narrowed the genetic base of agriculture sharply. A variety that is uniform and productive is also uniformly vulnerable: if a new disease or pest overcomes its defences, every field planted with it is at risk at once. Plant breeders then turn to old varieties, which may carry resistance that modern crops have lost. Storing seeds is cheaper and simpler than keeping plants alive in fields, but it is not a permanent solution. The seeds of many crops stay viable for decades when dried and kept at minus eighteen degrees Celsius, but each sample must eventually be planted, grown and harvested again to renew it. The task is costly, and many collections have a backlog of samples overdue for regeneration. The seeds of some important tropical crops, including cacao and coconut, do not survive drying at all and cannot be stored in this way. A further criticism comes from farmers. A seed stored in a vault stops adapting to the conditions in which it once grew, whereas a variety grown year after year in a particular valley continues to change as the climate does. Some farming groups therefore argue that the best store of diversity is the field itself, and that effort and money would be better spent helping communities keep growing traditional crops. Most managers of seed collections do not see the two approaches as rivals. They point out that the vault holds samples of varieties which have already vanished from farms, and that a community can borrow back its own seed if its harvest fails. Whichever view is preferred, it is worth noting how little the public knows about this work. Funding for seed collections is modest compared with spending on crop research, and is often among the first items to be reduced when budgets tighten. That seems short-sighted. A plant breeder cannot use a variety that no longer exists, and the loss of a seed sample is, unlike most losses in agriculture, completely irreversible.