Abstract
The genus Castanea (family Fagaceae) is found in north temperate
climates around the world, and is highly prized in many different cultures for
its nutritious nuts and valuable timber. Selection for larger, better-tasting
nuts has been ongoing in Asia and Europe for centuries. Early trade routes moved
European chestnut trees (C. sativa) west of their native range (in the
Caucasus mountains), and the Romans then moved them across their empire to
provide support posts for grapevines, as well as for the nuts. Cultivar
selection in Turkey, Italy, Spain, and Portugal has been extensive, and regional
favorites developed. The many uses of the wood of American chestnut made this
“all purpose” tree extremely valuable in its native range in North America. Nut
production was important as a food source for rural families and many species of
birds and animals. The other American species in the genus Castanea are
classed as chinquapins, and may be divided into several or lumped as a single
species. The small nuts from these trees and bushes serve primarily as mast for
wildlife. Two serious diseases of chestnut trees changed the direction of
chestnut research in the United States. Ink disease, caused by the root pathogen
Phytophthora cinnamomi, was discovered to be the cause of widespread
death of chestnuts and chinquapins in the southern United States, which had been
observed since about 1850. This imported pathogen probably came into the
southern United States before 1824. The second chestnut disaster was
the introduction of chestnut blight disease, which was first found in the United
States in 1904. The pathogen causing the lethal cankers is an Ascomycete now
known as Cryphonectria parasitica. The longest
continuing chestnut breeding program in the United States is in Connecticut.
