Adaptive variation in five conifer species across the Italian alpine ecosystems

Forest ecosystems form a dominant landscape in many alpine environments where natural populations of coniferous species are found across steep environmental gradients. Such populations are supposed to be tightly genetically adapted to these diverse environments; however the genetic basis of these adaptations is poorly understood. A preliminary investigation was conducted on five ecologically and economically important conifer species for the Italian Alps and Apennines: Abies alba, Larix decidua, Picea abies, Pinus cembra and Pinus mugo. To understand genetic patterns of adaptive variation, natural populations of these species were sampled along an altitudinal gradient and genotyped for single nucleotide polymorphisms (SNPs) markers. Population structure was estimated using Bayesian clustering analyses and a multivariate method, revealing the presence of 3 genetic clusters for A. alba and L.decidua, and 4 for P.abies, P.cembra and P.mugo. Inferred genetic structure was tested for correlation with latitude, longitude and the altitudinal gradient using multivariate analysis. Genetic variation resulted significantly correlated with geographic location in all five species: latitude was highly significant for A. alba and longitude for the other species. Further analysis on a local scale are needed to deeply investigate the altitudinal gradient effect and possibly detect outlier loci associated to climatic and environmental parameters