Back-Crossed American Chestnuts

We've got about 40 American chestnuts (Castanea dentata) on our farm, all grown from seeds. At least 20 are third-generation back-crosses with Chinese chestnuts (Castanea mollissima)

to develop resistance to a fungal infection called blight. Specifically, the blight is caused by an Asian bark fungus (Cryphonectria parasitica, formerly Endothia parasitica) accidentally introduced into North America on imported Asiatic chestnut trees in the Bronx Zoo in 1904.

In these photos, Diane is looking at the Spring buds. Among our varieties, the bark and buds are distinctly different between the two BC3 back-crosses we've planted (Hahn x OpAm and Cain x OpAm). The Hahn trees are faster growing with many Chinese qualities.

You can view the slides from a presentation I made for the Growing Native Program administered by the Chesapeake Bay Foundation and now the Potomac Conservancy.