Project Director

Craddock, J. Hill

Department Examiner

Shaw, Joey; Kovach, Margaret; Henry, Jim


Dept. of Biological and Environmental Sciences


University of Tennessee at Chattanooga

Place of Publication

Chattanooga (Tenn.)


The American chestnut tree (Castanea dentata) has been reduced from a key canopy hardwood to an understory shrub by the chestnut blight disease. C. dentata shares similar morphological characteristics with the Allegheny chinquapin (C.pumila variety pumila) and the Ozark chinquapin (C.pumila variety ozarkensis). Before the chestnut blight epidemic, the easiest and most obvious means of separating species of American chestnut and chinquapins was based on habit or flower morphology. C.dentata existed as a large tree, while varieties of C. pumila existed as shrubs or small trees; C. dentata contains three nuts per bur, while varieties of C. pumila contain one nut per bur. However, since the chestnut blight disease C. dentata has been restricted to an understory shrub or small tree that rarely, if ever, blooms. Now, overlapping morphologies between C. dentata and varieties of C. pumila are making it difficult to differentiate species. Such a population of Castanea currently exists in Floyd County, Georgia. Identifying these confounding trees is very difficult because the leaf morphology characterizes the population as C. dentata while the morphology of the flower characterizes the trees as C. pumila. In plant molecular systematic studies, chloroplast DNA sequences are a key source for establishing and resolving relationships between species. Noncoding regions of chloroplast DNA can be used to determine these relationships because there is a low level of evolutionary pressure acting on these noncoding sequences. By amplifying various noncoding regions of the chloroplast, a noncoding region that is found to be highly variable for a particular genus can be used in an attempt to distinguish between species in cases of taxonomic confusion. In an attempt to determine the identification of the confounding population of Castanea in Floyd County, Georgia, ten noncoding regions of the chloroplast were screened using chloroplast DNA from published reference standards for C. dentata, C. pumila variety pumila, and C. pumila variety ozarkensis.The results of this study indicate that there is at least one noncoding region of the chloroplast of Castanea that can distinguish between species of C. dentata, C. pumila variety pumila, and C. pumila variety ozarkensis, and can provide insight into the identification of the confounding population of Castanea existing in Floyd County, Georgia.


B. S.; An honors thesis submitted to the faculty of the University of Tennessee at Chattanooga in partial fulfillment of the requirements of the degree of Bachelor of Science.




American chestnut--Cytology; Chloroplast DNA--Analysis; Nut trees--United States


Plant Breeding and Genetics

Document Type



iii, 45 leaves





Call Number

LB2369.5 .K466 2008