Promoting climate adaptation of European larch through genetic evaluation, intrapopulation adaptive response, and GxE dynamics across Austrian landscapes

Ing. Valérie Poupon

Doctoral thesis

Abstract:

Climate change’s negative impact on forest communities around the globe is already visible and is expected to increase further in the near future. This is in part due to the rapid environmental changes against the lower rates of adaptation and migration capacity of tree populations. Understanding the complex relationship between climate and tree species is essential to establishing efficient management strategies, such as assisted migration, to cope with the inevitable changes. In this thesis, we focused on three commercially important traits, height, diameter at breast height, and wood density, of an Austrian European larch population that was planted across 21 sites. Based on the concept that trees within the same population of origin will react differently to the environment, the aim was to analyze its intra-population genetic variability and genotype by environment interaction (GxE) and to infer which environmental variables are likely influencing it. Two different types of methodologies were used in this thesis, the first one, which we developed, combines the response function methodology and tree breeding approach, while the second one is based on a complex factor analytic modeling that is mostly used in crop science but that is also newly used in tree species. According to our results, both methods were successful in detecting the studied genotypes' response variability and GxE. Furthermore, we were able to determine which environmental variables are likely to influence each trait. Within our studied range, height seems to be affected by temperature, altitude, and precipitation seasonality. Diameter at breast height seems to be affected by the mean diurnal range and wood density, though mildly, seems to be affected by altitude. In our opinion, both methodologies can be applied to describe the intra-population genetic variability and were able to identify key environmental variables affecting specific commercially important traits. We believe that this knowledge can be used to select well-performing genotypes that are adapted to specific conditions, and hence be used in tree breeding and conservation programs (e.g., for assisted migration) focused on helping trees to cope and adapt to changing environmental conditions.

Keywords

assisted migration, climate change, factor analytic, forest tree breeding, genetic diversity, Larix decidua, mixed model, multi-environment trials, response function

Language used: English

Date on which the thesis was submitted / produced: 21. 9. 2023

Thesis defence

• Supervisor: prof. Ing. Milan Lstibůrek, MSc Ph.D.
• Reader: Luboš Vostrý, Ph.D., prof. Ing., Jaroslav Klápště, externi, Daniel Gräns, externi

Czech University of Life Sciences Prague

Faculty of Forestry and Wood Sciences

Doctoral programme / field:
Forestry Engineering / Forest Biology