Fig. 1.

Geographic distribution and genetic structure of 94 aspen individuals. a Location of the 12 original sample sites of the SwAsp collection (circles) and the location of the two common garden sites (orange stars). The original collection sites span a latitudinal gradient of c. 10 latitude degrees across Sweden. b Genetic values for date of bud set for the 94 individuals included in the study across the two common gardens and three years (2005, 2006, and 2007). c Population structure in the SwAsp collection based on a PCA of 217,489 SNPs that were pruned to remove SNPs in high linkage disequilibrium (SNPs included all have r² < 0.2). Although two axes are shown, only the first axis is significant (P = 3.65 × 10⁻¹², Tacey-Widom test, 1.31% variance explained)