Norway spruce is the most important Swedish commercial tree species and provides the majority of the annual forest production and export in Sweden. Improved growth and at same or better wood properties are top priorities in tree improvement, or in other words accelerated breeding cycle and increased genetic gain. Unraveling the genetics behind wood juvenile-mature transition and MFA would be of great value to reduce the rotation age while avoiding undesirable effects from high microfibril angle typical of young trees. The aim of the study is to develop mathematical models to accurately estimate biologically meaningful parameters describing the microfibril angle transition from juvenile to mature wood (MFAj-m) in Norway spruce. Accurate estimation of such parameters will open up for the performance of association mapping analysis and new tools in tree improvement.

The project will consist of three major sequential steps:
Mathematical modeling of the genetically controlled part of the radial/time variation of MFA and, based on this, parameterization of the MFAj-m.
2. Estimation of the size of genetic variation, heritability, and breeding values for MFAj-m in the sampled population
3. Association mapping (AM) to identify the genes underlying MFAj-m…