On the origin and domestication history of barley (Hordeum vulgare)

Remains of barley (Hordelun vulgare) grains found at archaeological sites i n the Fertile Crescent indicate that about 10,000 years ago the crop was do mesticated there from its wild relative Hordeum spontaneum. The domesticati on history of barley is revisited based on the assumptions that DNA markers effectively measure genetic distances and that wild populations are geneti cally different and they have not undergone significant change since domest ication. The monophyletic nature of barley domestication is demonstrated ba sed on allelic frequencies at 400 AFLP polymorphic loci studied in 317 wild and 57 cultivated lines. The wild populations from Israel-Jordan are molec ularly more similar than are any others to the cultivated gene pool. The re sults provided support for the hypothesis that the Israel-Jordan area is th e region in which barley was brought into culture. Moreover, the diagnostic allele I of the homeobox gene BKn-3, rarely but almost exclusively found i n Israel H. spontaneum, is pervasive in western landraces and modern cultiv ated varieties. In landraces from the Himalayas and India, the BKn-3 allele IIIa prevails, indicating that an allelic substitution has taken place dur ing the migration of barley from the Near East to South Asia. Thus, the Him alayas can be considered a region of domesticated barley diversification.