ABSTRACT
The genus Castanea, within the family Fagaceae, is an important genus across much of the northern hemisphere’s forested ecosystems. Castanea contains seven species of deciduous trees and shrubs, classified into three sections-Eucastanon, chestnuts; Balanocastanon, chinkapins; and Hypocastanon, the Henry chestnut (Johnson 1988, Lang et al. 2007). The chestnuts comprises of fi ve species-Castanea dentata (Marsh.) Borkh., C. sativa Mill., C. crenata (Sieb & Zucc.), C. mollissima (Blume) and C. seguinii (Dode)—are typically most valued and have been most studied especially with respect to disease resistance, genetics of resistance and biotechnology. In Asia and Europe the chestnuts are primarily valued for nut production while in North America they were valued as multi-purpose forest trees providing a wide range of products for local populations through the Appalachian Mountain region. However, in both Europe and North America non-native diseases have limited nut and forest production and decimated the population, respectively (Anagnostakis 1987). Chestnut blight, incited by Cryphonectria parasitica (Murr.) Barr, entered the U.S. in the late 1800s, was fi rst detected in 1904 (Merkel 1905; Murrill 1906) and spread throughout the C. dentata range (800,000 km2) by the 1950s, infecting all remaining stands by the 1970s (Beattie and Diller 1954, Hepting 1974). Even prior to chestnut blight, ink disease or Phytophthora root rot, incited by Phytophthora cinnamomi Rand, was killing C. dentata in the southern part of its range (Crandall et al. 1945, Rhoades et al. 2003). The same diseases are killing C. sativa trees in forests and limiting nut production in orchards in Europe, while the Asian species of chestnuts (C. mollissima and C. crenata) have co-evolved resistance to these diseases as the pathogens are native to Asia (Crandall et al. 1945, Robin et al. 1998).
