A Bank-Like Vault for Plant Materials

From apples to zucchini, there isn't a crop on the planet that isn't impacted by pests, disease or the ravages of extreme weather in some way. Sometimes, a threat rises to catastrophic effect, such as the fungal disease that caused Ireland's potato famine of 1845 to 1852, or the tiny aphid-like insect that wreaked havoc in French vineyards in the 1860s, bringing France's renowned wine industry to its knees.

More recently, the Food and Agriculture Organization of the United Nations released a study in 2021 that estimated that up to 40% of global crop production annually is lost to pests. Each year, plant diseases cost the global economy more than $220 billion, and invasive insects cost at least $70 billion.

"The world is always changing. We're going to have a new disease, a new pest, a new climate that's warmer or cooler, wetter or drier," says Daren Harmel, research leader for the USDA Agricultural Research Service (USDA-ARS) National Laboratory for Genetic Resources Preservation, based in Fort Collins, Colorado. "Nature uses genetic diversity to propagate itself, so if we capture that diversity, the genes for combating those new threats are available."

IN A SAFE PLACE

When the USDA was created in 1862, one of its chief purposes was the collection, testing and distribution of seeds and plants. Today, those activities are carried out through the National Plant Germplasm System, which seeks to safeguard the genetic diversity of agriculturally important plants.

"It's kind of like the National Archives, the Library of Congress and Fort Knox all rolled up in one for crops," Harmel says of the facility. "Yes, we store seeds and other plant materials like a bank vault, but it's an active collective. The system distributes more than 250,000 crop accessions to breeders and researchers every year."

Located across the U.S. and Puerto Rico, the system comprises 20 sites, most of which are operated by the USDA-ARS in partnership with a land-grant university. Each active collection site is responsible for certain crops, while the Fort Collins site serves as the backup for all active sites -- a collection that contains more than a half-million uniquely identified plant and seed samples from nearly 12,000 plant species.

"I would be surprised if you could think of a crop for which we don't have accessions here at the repository," Harmel says. "Even crops that are grown in other parts of the world, we have collections of those. I think it's safe to say we're the largest and most diverse collection of agriculturally relevant plant germplasm in the world."

GERMPLASM STORAGE AND DISTRIBUTION

Crop breeders and other scientists may request germplasm from the collection for their research programs. The material might be seeds, but it could also be pollen or buds from vegetatively propagated crops such as apples or pears. The request may be fulfilled directly by an active collection site or from the Fort Collins repository. If supplies of a particular unique variety aren't sufficient for distribution, an active site will grow out a plot to increase available volumes.

When a new variety is developed, the crop's curator at an active site may deem it important to add it to the germplasm system.

"If it's soybean, for example, they essentially send us a bag of seeds," Harmel says. "We'll test those seeds for viability and make sure they'll grow. If they meet the standards, then they get put into storage."

Seeds are stored in a walk-in freezer that's about the size of a basketball court. The temperature inside is set to minus 18°C, or about 0°F. Vegetatively propagated crops are handled differently.

"You can't put an apple seed or a papaya seed in the freezer," Harmel says. "Those crops that are propagated by grafting a bud onto rootstock are maintained in the collection in liquid nitrogen tanks at minus 196°C."

Once an accession enters the collection, it's not locked away forever. Germplasm can degrade while frozen or cryopreserved, so maintenance of the collection is also a major focus at the Fort Collins facility.

"We have a team of scientists and technicians that works on the viability testing," Harmel explains. "For some crops, it's after 20 years. For others, it's a shorter time frame. If we see a decrease in viability, we'll let the active collection site know, and they'll grow out more so that we continue to have plenty of viable seed on hand."

The Fort Collins facility also is home to the National Animal Germplasm Program, which similarly works to preserve and maintain livestock genetic resources.

"What happens in the building here really does undergird the whole national agricultural production system, and it gives me a heck of a lot of pride to play a role in that," Harmel says. "It's amazing forethought by those men and women who developed the system. To understand the value and importance of genetic diversity, and to convince Congress to fund this is incredible. No one argues that these agricultural crops are vitally important to our nation or that the diversity we have needs maintained to protect our cropping system."

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