Geographical distributions of landraces for each of the barley populations identified at K = 9. The locations of the individual landraces are indicated and the circles are the standard deviation ellipses for each population. The locations of those landraces with a proportional population membership of ≥0.9 are shown by the large squares and their standard deviation ellipses are drawn in black. Landraces with a proportional population membership of < 0.9 are shown by the small dots, and the standard deviation ellipses obtained when these landraces are included in the analysis are drawn in colour. For an expanded view of the population 3 distribution, see Additional file 1, Figure S1.