Blight-resistant American chestnuts have been found in the wild, and a competing group with a similar name, the American Chestnut Cooperators' Foundation <http://www.accf-online.org/>, has a breeding project using only these non-hybrid trees. If I understand correctly, the hybrid chestnuts were selected not just for blight resistance but for desirable timber traits, which seems like a bad idea. I actually like the idea of genetically modified chestnuts better, as they are presumably closer to the pure native species than the hybrids are. Many individual plants might also be GMed, allowing for reestablishment from regional genotype. Lots of chestnuts throughout the range are not dead, but simply don't reach flowering size before they're killed to the ground again by blight. If a biological control were found or engineered, chestnuts might recover with a fair bit of the species' genetic diversity intact. Sean Z Zone 6a SE Michigan