Spatial principal component analysis of western <i>Cronartium ribicola</i> populations using Delaunay triangulation as connection network.

<p>The first positive eigenvalue component of the sPCA, corresponding to global structure, was plotted on the map. Each population is represented by a blue (positive scores) or red (negative scores) circle of a size proportional to the score loading. The bar represents a barrier to gene flow identified using the Monmonier algorithm in the R package <i>Adegenet</i>.