The phylogenetic relationships among the possible donors of B genome of common wheat based on internal transcribed spacer(ITS) sequences
用ITS序列确定小麦B基因组的可能供体间的关系

The ITS regions of 5 species in Aegilops sect. Sitopsis, the possible donors of B genome of common wheat, were amplified by PCR, cloned and sequenced. The phylogenetic relationships among 5 species in Aegilops sect. Sitopsis were constructed based on ITS1 ITS2 sequences. The results demonstrated that Ae. speltoides was a distinct species in Aegilops sect. Sitopsis. The average of the pairwise distances between Ae. speltoides and the other four species was three times as high as that among the latter four. Ae. speltoides was the earliest lineage of the section under question. Relationship between Ae. longissima and Ae. sharonensis was the closest in Aegilops sect. Sitopsis. Sequence of ITS region could be used as a molecular marker to identify origin of B genome in polyploid wheats.