Fig. 2

Genetic structure and phylogenetic relationships of the three Picea crassifolia groups (GS, QH and QL). a Admixture proportions of genetic clusters for each individual of the three groups and the resulting phylogenetic tree. The scenarios of K = 2 and K = 3 are shown. K = 2 has the best value according to cross-validation analysis. A maximum likelihood (ML) tree based on 120,855 SNPs with Picea wilsonii as the outgroup was constructed above the admixture result. b Principal component analysis (PCA) plot for the 82 P. crassifolia individuals based on the first two principal components