Abstract: Summary Chromosome pairing in the meiotic metaphase I of the pollen mother cells was studied using the F₁ hybrids between alloplasmic lines of common wheat, Triticum aestivum var. Chinese Spring (genome constitution AABBDD), as female and octoploid trititrigia (AABBDDEE or AABBDDFF) or hexaploid trititrigia (AABBEE) in order to know the effect of alien cytoplasm on meiotic chromosome behavior. Chromosome pairing in the hybrids of the cross-combinations (genome constitution AABBDDE or AABBDDF, or AABBDE) was ascribed to both the homologous and homoeologous chromosome pairing. The experiment shows that there is a homoeologous relationship between genomic members of common wheat and that of For Egenome. D² type cytoplasm promotes homoeologous but inhibits homoeologous chromosome pairing. S^v cytoplasm inhibits both homologous and homoeologous pairing. G-cytoplasm promotes homologous pairing. In the hybrids between alloplasmic Chinese Spring and hexaploid trititrigia, there was low seed-set rate and a confused meiosis, this maybe implies difference exists between E two genomes from Elytrigia intermedium and from E. Elongatum. G-, D²-, M^t- and M^u-type cytoplasmic male sterile octoploid trititrigia lines has been selected following backcrosses, and in these lines, the D²-cytoplasmic octoploid trititrigia possess a character of photoperiod sensitive male sterile; A normal fertility of G-cytoplasmic "Yz-3" means exist of G-type fertility restorer gene in the E genome of octoploid trititrigia line, "Yz-3".

Key words: Alloplasmic wheat, alloplasmic trititrigia, cytoplasm substitution, nucleo-cytoplasmic hybrid, male-sterile octoploid trititrigia