Ecoscience: Preserving Genetic Diversity With Seed Banks

By Paul And Anne Ehrlich
Published on May 1, 1982
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PHOTO: FOTOLIA/JOHNNY007PAN
Seed banks help protect plants, national security and more.

Humankind is fortunate that the extreme seriousness of the
loss of genetic variability of crops is balanced by the
relative ease with which the situation could be
improved. “Seed banks” can, you see, be used to preserve samples of
diverse crop strains, as well as populations of their wild
relatives. The seeds of most species will keep in cold
storage for a number of years before the majority of those
in each sample die. Every few years, then, it’s necessary
to sow the saved seed, allow the plants to mature and
harvest the seeds once again for storage.

The Need For Genetic Diversity

However, although seed banks are simple in principle, their
operation requires skill and care. The preservation of
samples often amounts to little more than allowing the
process of natural selection to choose those seeds that
most readily survive the storage conditions. Unfortunately,
seeds that survive well in storage don’t necessarily
produce plants with the characteristics that are most
useful to farmers.

The rate that a plant strain undergoes selection for
survival in storage can, however, be retarded by frequent
planting out. But it’s also important that seeds be planted in the region from which they came… or at least under
conditions very similar to those that occur in the home
area. Otherwise, the strains will lose their unique
characteristics, because — once again — selection
will gradually adapt them to their new environment.

Seed Banks Are Underfunded

A recent survey, conducted by the government’s General
Accounting Office (GAO), found that seed-bank operations
in the United States leave much to be desired. Our nation’s
main facility is the Department of Agriculture’s National
Seed Storage Laboratory at Fort Collins, Colo. Smaller
collections are held by various federal and state
experiment stations and by commercial seed companies.

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