Figure 3

Genetic and geographical structuring of wheat accessions. (a) PCA plot showing the relationship between the accessions belonging to the landraces (red dots) and modern varieties (blue dots). The modern elite variety ‘Divana’ from Croatia closely grouped with the landraces (black arrow). (b) Using representative coloring the number of accessions is shown as bars for each region. Darker shades and inserted numbers indicate modern varieties. A total of 266 accessions were included in our study (see Supplementary Table S5). (c) The ten regions are marked on the map from which the wheat accessions were collected using the same coloring. (d) Unrooted maximum likelihood (ML) tree generated with IQ-Tree, with overlayed genetic origin of the accessions; branches representing modern varieties (blue) and landraces (red). The well-supported (bootstrap > 90%) division (blue split) of modern varieties is marked with a black arrow. The position of ‘Divana’ is indicated with the second black arrow pointing to the blue branch nested within the red group of landraces confirming its close affinity. (e) Unrooted ML tree with overlayed representative coloring (see b and c) corresponding to the country of origin of the accessions. Arrows indicate well-supported groupings (bootstrap > 90%) in both ML trees (d and e) while the rest of the nodes received weak signal (< 35%). A general time reversible nucleotide evolutionary model with direct base frequency counts was used to infer topologies. The trees are draw to scale with branch lengths measured in the number of substitutions per site. The scale bar represents 0.2 substitution per site.