Here’s a (relatively) new approach to sustainable genebank conservation, from Chocolate in Context: sponsor an accession. The International Cocoa Genebank in Trinidad will accept donations from US$20, which saves one tree for one year, to US$500, which saves a whole plot (no idea how many trees that is) for 10 years. And another web site, called Yachana Gourmet, preserves a tree on a farm, not in a genebank, and gives you access to tasty chocolate and other goodies.