By Sharon Omahen
University of Georgia

Typically, the work of Gary Pederson's staff goes unnoticed and unappreciated. But if the unthinkable should ever happen and all the crops in the United States had to be replenished, they would be overnight heroes.

Pederson heads the Plant Genetic Resources Conservation Unit of the U.S. Department of Agriculture's Agricultural Research Service. The unit is on the University of Georgia College of Agricultural and Environmental Sciences' Griffin, Ga., campus.

Facilities across the nation

The USDA-ARS plant germ plasm system includes a main seed storage facility in Fort Collins, Colo., and repositories like the one in Griffin in Geneva, N.Y.; Pullman, Wash.; and Ames, Iowa. Collectively, these facilities serve as a modern-day Noah's ark for crops worldwide.

"The reality behind why our facility is here and why it's funded is to preserve genetic variability of crops for use today and in the future," Pederson said. "We currently house more than 82,000 seed or germ plasm samples of more than 1,430 crop species from more than 180 countries."

Pederson hopes the seeds will never be lost. Nonetheless, he makes sure every crop on his list is backed up. It's a lot like backing up your computer's hard drive.

"Long-term preservation of these materials is something everyone sees value in," he said. "If we had to stock our facility today, we couldn't do it. Many of these samples were collected years ago throughout the world. Today, the native plants may no longer be found in these areas, or access may be difficult."

The seed bank is stored either as seeds or as germ plasm or "plantlets."

"Most of our collection is stored as seeds," Pederson said. "But we also store tissue cultures of crops like sweet potatoes. We actually have 700 cultures of sweet potatoes alone."

Stored in freezers and refrigerators

Seeds are stored either at refrigeration (40 degrees Fahrenheit) or freezer temperatures (zero degrees).

"Most crops last longer at zero degrees," Pederson said. "Some hard-seeded crops like sorghum can last 30 to 50 years."

Pederson's goal is to store most seed in the collection at zero degrees. This would drastically reduce the times the seeds would need to be reproduced.

"Each time you regenerate, you take the chance of losing some of the sample's diversity," he said.

Seeds in the refrigerated collection are stored in resealable bags for easy access when requests are made. Those in the freezer storage are placed in foil, heat-sealed envelopes.

"The foil bags protect the seeds from moisture," Pederson said. "This really can come in handy if there is a roof leak or condensation buildup."

Though the collection is intended for long-term preservation, it's being used every day.

Plant breeders are primary users

"Scientists from across the globe request our materials for use in their research projects," Pederson said. "For instance, we house the national peanut collection, many of which are wild relatives of the varieties we eat. These wild relatives can be very useful in breeding new varieties because they may carry disease resistance, be more drought-tolerant or produce greater yields."

Pederson said researchers in Oklahoma recently requested samples of all 30,000 sorghum samples at the Griffin facility.

"They're fighting new biotypes of greenbugs and need material to breed resistance," he said. "Anytime a major crop pest or disease hits, we hear from the researchers who are working to fight it."

Other countries request samples of their native germ plasm as their own seed collection was lost or incomplete, he said.

The requests also come from nontraditional researchers. "Epcot has requested seeds for planting demonstration plots, and we've had requests for seeds of plants used historically in paper-making," Pederson said.

"In the past few years, we've averaged requests for 30,000 samples each year," he said. "And I'd love to see that rise to 50,000 samples per year. It shows that researchers are interested in and are using the germ plasm we maintain here."