Genetic variation and plasticity of drought reaction in Norway spruce (Picea abies (L.) H. Karst.) populations as revealed by x-ray densitometric measures of wood density

Rome

2010

S. 211

Bandaufführung

10692S

167266

In lowland forests of eastern Austria high temperatures, limited precipitation (e.g. in Vienna: precipitation sum May to August is 278 mm, mean air temperature from May to August is 17.8°C) and the occurrence of droughts limit tree growth, in particular that of Norway spruce (Picea abies (L.) H. Karst.). An increase in the frequency of temperature-induced droughts, expected due to climate change, seems to worsen this situation. We analysed tree cores from three provenance experiments with Norway spruce located in eastern Austria to identify drought-resistant provenances and drought-resistance genes. X-ray densitometry has often been used to investigate the relationship between maximum density and summer temperature at temperature-limited sites, and we used it to screen 1000 cores from trees of about 35 years old of 17 provenances. Trees from the most drought-affected trials (Porrau and Deutsch-Gerisdorf) showed significant growth reductions during drought events in 1992 and 2003. We characterized the effect of drought on various wood density and increment measures and analysed the genetic variation among the provenances. The plasticity of drought response of the provenances was analysed by comparing the responses of provenances in various trials and drought periods. The significant differences observed among provenances provide a basis for further provenance selection and for the setting up of collections of individuals with more or less drought sensitivity for genomic analysis.