Biological Invasions

, Volume 11, Issue 5, pp 1107–1119 | Cite as

The role of intraspecific hybridization in the evolution of invasiveness: a case study of the ornamental pear tree Pyrus calleryana

  • Theresa M. Culley
  • Nicole A. Hardiman
Original Paper


Hybridization between genetically distinct populations of a single species can serve as an important stimulus for the evolution of invasiveness. Such intraspecific hybridization was examined in Pyrus calleryana, a Chinese tree species commonly planted as an ornamental in residential and commercial areas throughout the United States. This self-incompatible species is now escaping cultivation and appearing in disturbed habitats, where it has the potential to form dense thickets. Using genetic techniques incorporating nine microsatellite markers, we show that abundant fruit set on cultivated trees as well as the subsequent appearance of wild individuals result from crossing between genetically distinct horticultural cultivars of the same species that originated from different areas of China. We conclude that intraspecific hybridization can be a potent but little recognized process impacting the evolution of invasiveness in certain species.


Callery Pear Evolution Intraspecific hybridization Pyrus calleryana Self-incompatibility 



The authors thank D. Ayers, N. Ellstrand and K. Schierenbeck for organizing the symposium that led to this special issue, as well as enlightening discussions and comments on the manuscript. K. Manbeck provided an invaluable perspective from the green industry while M. Klooster, S. Rogstad and two anonymous reviewers provided helpful suggestions that greatly improved the manuscript. This research was supported by a grant from the US Department of Agriculture, Cooperative State Research, Education, and Extension Service, to T.M.C. (USDA CREES 06-35320-16565).


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Copyright information

© Springer Science+Business Media B.V. 2008

Authors and Affiliations

  1. 1.Department of Biological SciencesUniversity of CincinnatiCincinnatiUSA

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