A high-density genetic linkage map of Aegilops tauschii, the D-genome progenitor of bread wheat

Aegilops tauschii is the diploid D-genome progenitor of bread wheat (Tritic um aestivum L. em Thell, 2n = 6x = 42, AABBDD). A genetic linkage map of th e Ae. tauschii genome was constructed, composed of 546 loci. One hundred an d thirty two loci (24%) gave distorted segregation ratios. Sixty nine probe s (13%) detected multiple copies in the genome. One hundred and twenty thre e of the 157 markers shared between the Ae. tauschii genetic and T. aestivu m physical maps were colinear. The discrepancy in the order of five markers on the Ae. tauschii 3DS genetic map versus the T. aestivum 3D physical map indicated a possible inversion. Further work is needed to verify the discr epancies in the order of markers on the 4D, 5D and 7D Ae. tauschii genetic maps versus the physical and genetic maps of T. aestivum. Using common mark ers, 164 agronomically important genes were assigned to specific regions on Ae. tauschii linkage, and T. aestivum physical, maps. This information may be useful for map-based cloning and marker-assisted plant breeding.