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Abstract

In the forest of the “Leipzig Canopy Crane Project” (LAK), the common ash (Fraxinus excelsior) is the dominant tree species. This ash population is most likely the result of different phases of plantings after 1800. In the LAK study plot, 64 adult individuals exceeding 22 m in height and a large number of seedlings and saplings show a high phenotypic variation. In the present study, the genetic variation of the semi-natural population of F. excelsior is analysed. The main questions are whether phenotypic variation is reflected by a genotypic variation, and how large the genetic variability of the population is. The establishment of microsatellite and AFLP markers for analyses of the LAK ash population is described as well as first results. One main result is that the ash population possesses an astonishingly high level of genetic variation within this population, especially regarding the putative origin and strong selection of this forest during the last centuries. Because of this high variability in microsatellite markers all individuals analysed in this first screening could be identified via individual DNA fingerprinting. After a first test of utility of microsatellite and AFLP markers a screening of a set of 77 individuals of the LAK plot containing 220 samples is in progress. Additionally to the comparison of the geno- and phenotypic variability of the ash population – especially in floral phenology – in future studies it is planned to compare this semi-natural with a natural population, and based on the high genetic variability, investigate the role of somatic mutations in genetic diversity.