Heterogeneous patterns of genetic variation at nuclear genes and quantitative traits in a Scots pine provenance trial
We studied the genetic variation in a set of nuclear genes analyzed from 16 populations of Scots pine derived from a 50-year-old provenance trial in Poland. At the same set of loci, the pattern of genetic variation was compared to several reference populations from a latitudinal gradient in Northern and Central Europe. Similar levels of nucleotide diversity were observed between the defined groups of Polish populations representing three climatic regions (π<sub>total</sub> = 0.0040–0.0051) in comparison with the reference samples (π<sub>total</sub> = 0.0054–0.0058). Polish populations showed minor but heterogeneous patterns of genetic variation between regional groups (<em>F</em><sub>ST</sub> up to 6%), which were caused by differentiation at specific loci. When outlier loci were excluded from between group comparisons, there were no differences between the Polish populations. Loci related to glycosyltransferase and laccase were identified as outliers, and were correlated with phenotypic differentiation using mixed-linear models. Moreover, these genes were also found as being potentially under selection across the Scots pine distribution range as the patterns of nucleotide variation correlated with latitude and altitude of the maternal stands. The provenance trial measurements have characterized a set of growth and developmental traits over 50 years and forms a suitable experimental system for detailed genetic studies.