Cluster structure of barley (Hordeum vulgare L.) populations at hordein-coding loci in countries of Southwest Asia, North and Northeast Africa, the Middle East, and South Arabia

The cluster population structure of barley landraces with known sampling localities in nine countries of Southwest Asia, the Middle East, North and Northeast Africa, and South Arabia was examined using the allele-frequency data for three hordein-coding loci. A total of 92 populations from Turkey, 56 populations from Syria, 34 from Jordan, 23 populations from Iraq, 6 from Morocco, 16 from Algeria, 34 populations from Egypt, 100 from Ethiopia, and 71 populations from Yemen with known sampling localities were included in the analysis. It was demonstrated that the cluster population structure in different countries was different and varied from a single cluster in Morocco to five clusters in Ethiopia. Furthermore, populations with sampling sites located at a considerable distance from one another were grouped into one cluster. It is suggested that the existence of several population clusters within a single country can be evidence of repeated population introduction, while the grouping of the populations with sampling sites considerably distant from one another into one cluster can indicate the distribution of once introduced populations of cultivated barley within countries through local farmer migration.