Genetic Structure Characteristic of Aegilops tauschii from Different Geographical Populations and the Origin of Chinese Population

As the diploid progenitor of common wheat, Aegilops tauschii is used as a genetic resource for improving common wheat. In this study, the genetic differentiation index between Yellow River (Shaanxi and Henan) and Xinjiang groups (0.322, 0.377) were obviously higher than between the former and Central Asia groups (0.231, 0.289). Meanwhile, the genetic distances between Yellow River (Shaanxi and Henan) and Xinjiang groups (0.285, 0.329) exhibit larger values compared with those between the former and Central Asia groups (0.283, 0.321). These results reveal that the genetic constitution of Yellow River and Central Asia groups is of more similarity compared with Xinjiang group. The phylogenetic tree demonstrates that Ae. tauschii in Yellow River and part of that in Central Asia are firstly gathered to be a subset. Then the subset and Xinjiang group are classified into a clade, which could be assigned to Central Asia and Middle East populations, implying that Ae. tauschii in Yellow River has a closer relationship with part of that in Central Asia compared with Xinjiang. Our finding further clarifies that Ae. tauschii in Yellow River might be directly derived from one/several types from Central Asia such as Turkmenistan, Pakistan, and Afghanistan.