Using DNA Markers to Distinguish Among Chestnut Species and Hybrids
Identification of American chestnut trees in the wild for inclusion in breeding programs is currently done using morphological traits. Distinguishing traits include leafshape, stipule size, presence or absence of leaf and stem trichomes, and stem color. Application of these traits is reasonably clear if the trees are pure American chestnut, but identitication of hybrids is very difficult. Hybrids that are primarily American chestnut may look like American chestnut. Such individuals can be frequently found in densely forested areas because of extensive plantings of species and hybrids in public and private woodlots. Since the breeding programs are designed to include as much native diversity of American chestnut as possible, positive genetic identification would be very helpful.