A seed catalog from a century ago would reveal a much wider variety of seeds than available today.

That is because, in the early 1900s, agricultural practices shifted. Individuals stopped growing their own food, using plants that would thrive locally, and started buying it from stores.

Food is now mostly produced through large-scale farming methods. That includes, for example, a practice called monocropping, in which a single variety of plant is planted year after year.

Also, a few, large companies are patenting both seeds and plant genes, claiming ownership. Thus, with the rise in monocropping and industrial agriculture, the variety of seeds has declined substantially.

Bill McDorman, executive director of Native Seeds/SEARCH, says the resulting loss of genetic diversity creates food insecurity, because - as the Irish potato famine famously illustrated - planting a single seed means an entire crop can be wiped out by a single virus or pest.

"And that is what we are really setting ourselves up for," says McDorman.

One mission of Native Seeds/SEARCH is to locate, preserve and make available to the public those heirloom seeds that do still exist, particularly those varieties that used to thrive in the Southwest.

McDorman says the organization sees itself as a seed steward, with the goal of getting seeds, including those from ancient plants, into the ground once again.The organization, for example, has seeds for the Teosinte plant, a wild grass that is the ancient ancestor of corn.