The chestnut resurrection

摘要

Ihey're hard to breed and easy to kill," says plant pathologist Fred Hebard as he attacks a 2-metre-tall chestnut tree in southwest Virginia. Hebard bores a hole in the bark and squeezes a mash of orange fungus into the wood. The tree is a hybrid of the Chinese and American chestnut species, and Hebard hopes that it has enough resistance genes to keep the fungus - called chestnut blight - at bay. If so, the hybrid could help to resurrect a long-gone icon.