Project Director

Craddock, J. Hill

Department Examiner

Shaw, Joey; Biderman, Michael; Rehyansky, Katerine

Department

Dept. of Biological and Environmental Sciences

Publisher

University of Tennessee at Chattanooga

Place of Publication

Chattanooga (Tenn.)

Abstract

Two species of Castanea Mill. (Fagacae) are native to North America: the tall, forest-type Castanea dentata (Marsh.) Borkh. and the smaller, shrubbier Castanea pumila (L.) Miller. There are two varieties of C. pumila: Castanea pumila var. pumila, and Castanea pumila var. ozarkensis (Johnson, 1988). In the early 1900s, chestnut blight caused by Cryphonectria parasitica (Murr.) Barr. reduced C. dentata to stumps and sprouts and severely diminished the abundance of both subspecies of C. pumila. Because Castanea species can apparently interbreed, restoration efforts have been complicated by possible hybridization between the two now shrubby species. One of these putative hybrid and confounding populations, referred to as the "Pocket"population, was recently found in northwest Georgia. The present study sought to create an objective measuring system that separates and identifies four different morphological types: Pocket or Intermediate, typical C. dentata, typical C. pumila var. pumila, and typical C. pumila var. ozarkensis, using phenotypic characteristics. These phenotypic characteristics are based on a diagnostic morphometric variable guide defined by Diskin et al. (2006). Secondly, these phenotypic results were compared with the results from a chloroplast DNA study performed on the same samples (Binkley et al., submitted) to shed light on the confusing leaf morphology exhibited by southeastern Castanea populations. It was found that the constructed system could separate C. pumila var. pumila from C. dentata and the Pocket/Intermediate types. The current study corroborates Binkley et al. 's (submitted) findings of haplotype sharing. The failure to show morphological distinction among all four taxa may be due to the collecting methods which led to the variability of plant morphology, and incorrect or incomplete morphometric variables.

Degree

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.

Date

3-2009

Subject

American chestnut--Morphology; Chestnut blight; Chestnut--Varieties--North America

Discipline

Natural Resources and Conservation

Document Type

Theses

Extent

v, 55 leaves

DCMI Type

Text

Language

English

Call Number

LB2369.5 .D564 2009

Rights

http://rightsstatements.org/vocab/InC/1.0/

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