Phenotypic plasticity in Populus trichocarpa clones across environments in the Nordic-Baltic region

Transition towards a bio-based society requires large amounts of woody biomass to be converted into biofuels and biomaterials. Populus species are good candidates for growth in short rotations, but there is a lack of climate-adapted plant material suitable for growth at the high latitudes of the Nordic-Baltic region. Here we studied the growth and phenology traits in 63 Populus trichocarpa clones earlier preliminary selected for growth at northern latitudes, in three different field sites; i.e. in central Sweden, eastern and western Latvia. The material showed moderate broad sense heritabilities, with high values for phenology traits, indicating opportunities for selection. Genotype x environment (g x e) interaction was identified for all traits, but the phenotypic correlation between pairs of sites provided more detailed information indicating the strength of the g x e interaction. The between-clone variation in plasticity was high, and we identified some clones showing a high and stable performance across the three sites. These clones are of particular interest for the commercial deployment and future breeding of Populus material for the Nordic-Baltic region.