The characterisation of genetic diversity of common ash (Fraxinus excelsior L.) in Ireland and around Europe

Abstract

Fraxinus excelsior (ash) is a native tree species in Ireland and is economically important for the production of timber that is strong, elastic and light. Having migrated after the last glaciation from mainland Europe, it formed an important constituent of the mixed broad-leaf woodland that was predominant in Ireland prior to the expansion of agriculture. Woods containing native stands of common ash are rare in Ireland today. The primary aim of this thesis was to examine the extent and patterns of genetic variation present within Ireland’s F. excelsior, and to compare it to populations from around Europe. Molecular markers were used to assess diversity levels and to determine if provenances of ash were genetically distinct from each other, and if they formed geographically meaningful patterns. Using a combination of chloroplast microsatellites, nuclear microsatellites and AFLP markers the genetic diversity of F. excelsior in Ireland was found to be high and comparable to levels detected in other populations sampled within Europe (in this study and by others).