Genetic Variation of Beech (Fagus sylvatica L.) Along an Environmental Gradient

European beech (Fagus sylvatica L.) is one of the most important deciduous tree species in Central Europe. Because climate change models predict higher annual mean temperatures in addition to decreasing precipitation during the summer months for this region, the adaptation potential of beech (e.g. in regard to drought stress tolerance) is of large interest.

Beech populations along a climatic gradient and in different environments in Northern Germany were selected for this study. The analysis of selectively neutral genetic variation showed that the genetic diversity is high for all sampling sites and does not differ significantly between the populations. Furthermore, the genetic variation of genes was investigated which probably have an impact on adaptive traits like bud phenology and drought stress tolerance. It was possible to identify, sequence and to analyze ten different candidate genes (in total, 4038 bp in exons and 4107 bp in introns). Sixty-three SNPs (Single Nucleotide Polymorphisms) and 11 indels (insertions/deletions) distributed over the studied genes were detected. Comparisons of the populations with different amounts of precipitation showed that some SNPs are significantly different between the populations. They might be involved in the adaptability of beech.

Additionally, a translocation experiment with 3,600 beech saplings originated from the above-mentioned populations was established. It will facilitate an association of phenotypes (bud phenology and drought stress tolerance) with variation in the investigated and further identified candidate genes.