For example, of the 7,000 apple varieties available in the U.S. in 1900, over 5,000 were lost, and the remaining number was steadily declining. Several organizations have been established to preserve heirloom varieties of open-pollinated plants. The National Seed Storage Laboratory in Fort Collins, Colorado, is the primary seed bank in the United States with the responsibility for preserving seed of agricultural crops. Its primary focus is to store seeds that will help preserve the genetic diversity, and thus the survival, of crop plants. As part of the National Plant Germplasm System, a network of federal, state, and private organizations and individuals dedicated to the same goal, the laboratory also stores germplasm for other countries and permits free and unrestricted exchanges of its collections to researchers and breeders.
Seed banks are critical in the effort to preserve the genetic diversity of agricultural crops.
However, crops must be grown in the field so that they can continue to co-evolve with pests and diseases and develop resistance to them if they are to survive in the long run.