Scatter plot of 59 cultivated and 99 Tibetan wild barley genotypes based on the first two principal component analysis (PCA) axes. The percentage of variance explained by each axis is indicated. The red and green symbols represent Tibetan wild and cultivated barleys, respectively. P1 to P7 represent the subpopulation from 1 to 7, respectively.
Cai et al. BMC Plant Biology 2013 13:35 doi:10.1186/1471-2229-13-35