The mission of the U.S. National Plant Germplasm System (NPGS) is to effectively
collect, document, preserve, evaluate, enhance, and distribute plant genetic resources
for continued improvement in the quality and production of economic crops important
to U.S. and world agriculture. Plant genetic resources in the NPGS are made freely
available to all bona fide users fo r the benefit of humankind. The active collection is
maintained and distributed by 19 national repositories, and the base collection is
preserved at the National Seed Storage Laboratory (NSSL), U.S. Department o f Agriculture,
Fort Collins, Colorado. The NPGS collections include 40,477 sorghum and
1,507pearl millet accessions. Of the 20,169 sorghum accessions in the base collection
at NSSL, 80% are in conventional storage at about -18°C and 20% are in cryostorage
in vapor phase above liquid nitrogen at about -16(fC; the pearl millet collection is in
conventional storage. The International Crops Research Institute for the Semi-Arid Tropics (ICR1SAT)
located at Patancheru, near Hyderabad, India, has assembled a collection o f35,643
sorghum and 21,195 pearl millet accessions, both ICRISAT mandate crops. All these
accessions are maintained andpreserved in aluminum cans in the medium-term storage
facility at about 4°C and 20% relative humidity. Freshly rejuvenated accessions with
at least 90% viability and about 5% seed moisture content are being placed in moisture
proof aluminum foil packets that are vacuum sealed and stored in long-term storage at
-20°C. For these crops, 17% o f the sorghum collection and 23% o f the pearl millet
collection have been transferred to long-term storage
