Predicting the functioning and evolution of interspecific hybridisation in the context of climate change

The objective of this thesis is to assess the genetic and functional consequences of intra- and interspecific hybridisation. Hybridisation is one of the possible mechanisms of genetic adaptation of forest stands, with positive or negative consequences in the context of climate change.

We suggest modelling the adaptive impacts of the hybridisation of the native silver fir (Abies alba Mill.) in mainland France, a species vulnerable to climate change, with more drought-resistant provenances and species of the genus Abies. To this end, we will modify an existing physio-demo-genetic model (PDG), by simulating tree growth, survival, reproduction, migration and genetic evolution at the population level, in order to incorporate the presence of 'sister' species exchanging genes. We will focus on functional traits related to bud break date, stomatal closure, and vulnerability to cavitation. These functional traits determine drought risk and late frost risk, which are the two main climate-related risks affecting Mediterranean fir trees.

The thesis work will contribute to the development of a generic modelling tool to assess the consequences of hybridisation between sister species. The thesis will address without bias the possible positive consequences of hybridisation (genetic enrichment, mitigation of the risk of decline), but also negative consequences (risk of maladaptation, risk of local genetic diversity loss) associated with climate change.