Saving seeds for planting viable futures

By Gary Raham
Nature Writer and Illustrator

Not long after coming to Colorado, a friend introduced me to the Anasazi bean, an incredible time capsule at least partially fashioned by the labors of 60 generations or so of southwest Indian farmers.

The Anasazi Indians bred and cultivated this pinto bean relative from Mexico into a food crop high in protein, which nicely complemented the nutritional deficiencies of corn. The Anasazi saved beans in clay pots and left some in their cliff dwellings when drought and aggressive neighbors forced them out of their Four Corners homes.

In the 1950s, archival seeds were found, along with a few plants growing wild. A California accountant, Ernis Waller, and agronomist Bruce Riddell made this bean commercially available in 1983, helping preserve the labors of countless Anasazi farmers and save the genetic richness of this food crop from near extinction.

Today, scientists around the world are trying to preserve such biodiversity in a more systematic fashion. The stakes are high: sufficient food for a world population that exceeds six billion people that need both room to live and area to grow crops. The national, if not the world, capital for such efforts is Fort Collins at the National Center for Genetic Resources Preservation.

Not long ago Greg Holman, a biochemistry lab technician at the seed lab, turned up on one of my naturalist hikes, where I point out the animals and plants that once filled the landscape we humans tend to appropriate for our own uses. The NCGRP is the only place in the nation that stores seeds, cuttings, tissues or other plant propagules that can be regenerated into whole plants. (The center also stores semen and embryos of many animal species as well.) A tour of NCGRP and its web site (www.ars-grin.gov/ncgrp/) is an eye-opening experience.

NCGRP technically stores accessions, which are defined as "items in a collection." Each accession represents the pool of genes that defines a particular living entity. It comes with a title (species, population, parental line), editor (collector or breeder) and a brief summary that includes information on appearance and the date of collection - all available in a computer database. Physically, an accession will be a collection of 3,000 to 5,000 seeds, a straw of animal semen, a plant tissue culture, or buds from twigs of a fruit crop.

Seeds make great accessions when they can be successfully cooled, dried or frozen in liquid nitrogen. Unfortunately, some seeds are recalcitrant and become damaged by such measures. Temperate-zone trees, riparian species and tropical plants often fall into this category. Oak seeds, wild rice and citrus are common examples. Preservation of these plants involves procedures like cutting out the growing part of the seed, adjusting the water content and cooling very rapidly.

The NCGRP in Fort Collins stores about 475,000 plant accessions (5,000 species overall). They have the capacity of storing up to 1.5 million accessions in storage vaults chilled to minus 18 C. They also can store about 3,000 seeds and 70,000 semen accessions in each of 220 cryotanks containing liquid nitrogen. Seeds may survive 100 years at minus 18 C and perhaps a thousand years stored in liquid nitrogen.

But seeds can't be stored and forgotten. Periodically, seeds must be revived and planted to make sure they are still viable. One of the ongoing research projects at NCGRP, according to Patricia Conine, supervisory biological science laboratory technician for plants, is to find biochemical tests that will determine viability, because each time a crop is grown there is risk of infection by pests and changes in the genetic makeup of the particular species or strain.

NCGRP's task of preservation represents one component of the U.S. Plant Germplasm System. Regional Plant Introduction Stations maintain working collections of seeds for the day-to-day use of research scientists. National Clonal Germplasm Repositories maintain living plants to preserve different varieties that would be lost as stored seeds. The National Germplasm Resources Laboratory in Beltsville, Md., serves as the hub for plant exploration activities and germplasm exchanges, while the National Plant Germplasm Quarantine Center inspects and tests foreign plants introduced into this country for harmful pests and diseases.

Although many potential food crops exist, most of the world depends on a handful of grains like corn, wheat and rice. Of those, certain strains are often grown to the exclusion of others. The United States got a wake-up call on depending too heavily on one kind of grain in 1970, when corn leaf blight destroyed 15 percent of the national corn crop (700 million bushels). This event, in part, led to the creation of a formal National Plant Germplasm system.

Evolving diseases, shifting climate patterns, pollution and other stresses constantly demonstrate that rich plant diversity provides critical genetic resources humanity can't afford to lose. One major crop failure in a season may raise prices, a series of them could starve thousands, cripple a country, even destroy a civilization.

According to The American Farmland Trust, farmland currently disappears at the rate of 11,300 acres every day in the United States, making growing enough diverse crops yet more difficult. Even the Anasazi bean, a hardy legume fine-tuned to the arid Southwest, failed to support its human cultivators when an extended drought struck. Hopefully, the plant and animal collections at NCGRP will provide the gene bank reserves needed to survive and prosper in an uncertain world.

The public is welcome to tour the center in Fort Collins. Information is available by contacting Conine at patricia.conine@ars.usda.gov or calling 495-3225 for more information.