Abstract:The cytogenetics of the backcross generations and self-bred progenies (BC2F1, BC3F1, BC2F2, BC3F2 and BC2F3) of intergenetic hybrid of Triticum aestivum L. x Eremopyrum orientale (kedeb) Jaub. Et Spach were studied. The results showed that the plants BC3F1 (2n = 43 ) isolated from the backcross generations of the plants (2n = 44 ) accounted for 41.09%, but the plants (2n = 44) isolated was only 4. 11%, and the plants BC2F2 (2n = 44) isolated from self-cross generations of the plants BC2F1 (2n = 44) accounted for 13.21%. The number of univalents in pollen mother cells was higher in some plants (BC2F1) and the averages of univalents were negatively related to the backcross seed-setting and self-cross seed-setting with a related coefficient of － 0.6766* and －0.7429* respectively. The results of genomic in situ hybridization (GISH) showed that some plants of BC2Fs (2n=44) contained different number of alien chromosomes. All those indicated that alien chromosomes caused unusual pairing and segregation of wheat homologous chromosomes and also lowed the hereditary stability of wheat chromosomes.