There, the ARS Plant Genetic Resources Conservation Unit (PGRCU) serves as an invaluable resource for farmers facing tough growing conditions.

PGRCU, part of the National Plant Germplasm System (NPGS), maintains a varied collection of plant genetic resources, including legumes, sweet potatoes, peppers, squash, annual clover, eggplant and sorghum, among others. Led by research leader Gary Pederson, the unit holds more than 82,000 plant samples called accessions.

In the last three years, PGRCU has sent more than 110,000 plant germplasm samples to domestic and foreign growers and to researchers. By maintaining a repository of plant germplasm, it's possible for varieties used in the past in similar environmental conditions to be used now or in the future, as conditions dictate.

Growing conditions vary every year. Each plant variety thrives in specific, preferred conditions. Thanks to the efforts of a consortium of labs that make up the NPGS, the varieties are available — and will remain so — to researchers, educators and producers.

The researchers who are germplasm curators have the very important task of safeguarding samples of all agriculturally important crops. Through a national network, samples of crop plants are maintained as a means of safeguarding agriculture's productive capacity as well as for filling worldwide requests. However, keeping the seeds and plant samples alive takes work.

For example, samples stored as seed are dried, cleaned and packaged before being put in cold or freezer storage. Some seeds, such as clover and sorghum, can last for 30 or 40 years in freezer storage. Each accession is entered into the Germplasm Resources Information Network (GRIN) database, operated by the GRIN Database Management Unit, in Beltsville, Md.

ARS is the chief scientific research agency of the U.S. Department of Agriculture.