Fig. 4

Analysis of the population structure of 384 P. deltoides Individuals. (a) Principal coordinates analysis (PCoA) of 384 individuals from six provenances. : the provenance population in Missouri, USA (‘Mis’); : the provenance population in Iowa, USA (‘Iow’); : the provenance population in Washington State, USA (‘Was’); : the provenance population in Quebec, Canada (‘Que’); : the provenance population in Louisiana, USA (‘Lou’); : the provenance population in Tennessee, USA (‘Ten’). Red circle area: Group I; Blue circle area: Group II. (b) Relations between the number of K and ΔK, based on the model developed by Evanno et al. [33]. (c) The population structure of P. deltoides determined using STRUCTURE 2.3.4 [34] software (K = 2). Red area: Group I; Blue area: Group II. ‘Mis’, ‘Iow’, ‘Was’, ‘Que’, ‘Lou’, ‘Ten’: different provenance populations respectively