Abstract:In order to provide science-based information on the possibility and probability of gene introgression from common wheat (Triticum astivum) into Aegilops. The artificial indoor hybridization was conducted using 7 genotypes from 4 wheat relative species as female, and common wheat as male. The result indicated that different species had variable cross-ability. Among the 4 Aegilops species, the highest hybridization rate was from the combination of Ae. tauschii ? T. aestivum (46.49% for genotype Ae42, 22.58% for Y92), the second was from Ae. ovata ? T. astivum (14.76% for Y100, 12.11% for Ae23), the third was from Ae. cylindrica ? T. astivum (2.23% for Ae7, 8.50% for Y145), the lowest was from Ae. speltoides ? T. astivum (0.19%). Hybrid embryos from different combinations had different ability of callus initiation and germination. The hybrid embryos from A. ovata / T. eastivum and Ae. tauschii / T. eastivum had higher level of callus initiation and germination, Ae. cylindrica / T. eastivum had medium level, while the Ae. speltoides had lower level. The interspecific hybrids between Aegilops and common wheat had very low fertility. In backcrosses, the seed-set rate of hybrids of Ae. ovata / T. aestivum was 3.71% and 4.36% respectively backcrossed with male and female parents, while for hybrids of A. cylindrica / T. aestivum, it was 0 and 0.33% respectively, and for A. tauschii / T. aestivum, 0.33% and 0 respectively. On selfing of the hybrids, the seed-set rate was 0 (no seed set from 9750 florets) for the combination of Ae. cylindrica / T. aestivum, 0.044% (3 selfed seeds out of 6870 florets) for A. ovata / T. aestivum and 0 (no seed set from 7253 florets) for A. tauschii / T. aestivum. The study suggested that the probability of gene introgression from T. aestivum into Aegilops species was very low in nature.