Hardiman, Nicole , Culley, Theresa M. .
Intra-specific Hybridization as a Mechanism of Invasiveness for Pyrus calleryana.
Although many invasive species exist and are extremely costly in terms of damage to agricultural and natural areas, little is known about the initial evolution of invasiveness in plants. Intra-specific hybridization may be a key mechanism of invasiveness in an introduced species but as of yet, has not received much attention. This is being examined in Pyrus calleryana Decne., an exotic ornamental pear tree comprised of several different cultivars (e.g. "Bradford") that has begun appearing in natural areas in 23 states and has recently been listed as an invasive, exotic plant in Delaware, Tennessee, and New York. The purpose of this study was to investigate whether the spread of P. calleryana into natural areas is primarily caused by hybridization of different ornamental pear cultivars. Microsatellite analysis has been used to examine the genetic structure of several different cultivars, as well as to quantify the population genetics of wild populations and their putative parental sources. Twelve simple sequence repeat markers originally developed for Malus spp. and Pyrus spp. were used for analysis. The hypothesis was that parental genotype sources of invasive individuals are cultivars that have been planted in surrounding areas. Genetic similarity within and among cultivars was determined, as well as the degree of hybridization in wild progeny of cultivated individuals. The study of this species is unique in that spread of P. calleryana into natural areas has only just begun, which presents the opportunity to understand the genetic mechanisms of invasion of exotic species into new environments. Additionally, there may be the opportunity to make generalizations about adaptation of other plant species to new habitats.
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1 - University of Cincinnati, 816 Rieveschl Hall, Cincinnati, Ohio, 45221, USA
2 - University of Cincinnati, Department of Biological Sciences, 614 Rieveschl Hall, Cincinnati, Ohio, 45221, USA
Presentation Type: Oral Paper
Date: Monday, August 15th, 2005
Time: 1:30 PM