Origin Traceability and Genetic Structure Analysis of Picea abies Based on Nuclear Microsatellite Markers

As pressures from climate change and global trade increase, developing cost-effective tools for origin tracking becomes essential to ensure the traceability and adaptability of forest reproductive material (FRM). Our objectives were (a) to test the efficiency of a set of nuclear microsatellite loci (nSSR) for revealing the genetic structures identified by high-input sequencing studies and (b) to verify this set of nSSR loci for genetic assignment of commercial seed lots into reference regions. We used 12 nSSR markers to genotype 220 trees from 11 populations representing the eastern Baltic, Scandinavian and southern European ranges of Norway spruce. The results showed that the populations from the eastern Baltic range had relatively higher allelic diversity parameters. The Bayesian clustering revealed a geographically consistent genetic structuring of Norway spruce populations by distinguishing the eastern Baltic from southern European and Scandinavian populations. GENECLASS analysis correctly assigned Lithuanian commercial seed lots into the Lithuanian reference region with markedly higher probability than to any other reference regions. Our study demonstrates promising results for origin identification of Norway spruce, particularly in contexts where high-resolution genomic approaches remain financially or logistically inaccessible.