Since 1904 the chestnut blight was discovered in the Bronx Botanical Garden, citizens and scientists have been searching for a way to help the American chestnut survive and thrive in the hardwood forest of the Appalachian range. By 1950 most every American chestnut tree had succumbed to the deadly bark fungus cryphonectria parasitica which travels easily by millions of spores.
Early scientist tried to isolate infections and protect trees to no avail. The U.S. Department of Agriculture experimented with hybrid Chestnuts: Americans crossed with Chinese trees, which can tolerate blight and survive. These trees did not show much promise and the program was abandoned. The American Chestnut was relegated to a functionally extinct forest shrub re-sprouting from old root collars before they could produce new nuts.
In 1980, a corn geneticist named Charles Burnham along with a small group scientists came up with a plan to transfer Chinese resistance to the American Chestnut via a six generation backcross method. The American Chestnut Foundation was formed and started to implement the Burnham plan.
Fast forward 35 years and the American Chestnut Foundation's final generation of trees is not displaying the blight resistance expected. Recent genetic analysis of American and Chinese trees are yielding shocking new evidence that there are far more genes involved in blight resistance than originally thought. As this new evidence is being discovered, SUNY has figured out how to "splice" an anti-fungal wheat gene into a pure American Chestnut embryo and grow transgenic trees with good blight resistance. This transgenic Chestnut is now going through the federal regulatory approval process before it will be allowed out into the wild.
To further confound restoration, phytophthora cinnamoni a root rot disease further challenges American trees and gives us another variable for which to select.
What do these new discoveries mean for the American Chestnut Foundation and the future of the American Chestnut?