易组"太谷核不育基因"(Ms2)基因定位的研究

将在远缘杂交中由普通小麦（AABBDD）4D染色体易组导入六倍体小黑麦（AABBRR）以及硬粒小麦（AABB）的太谷核不育基因Ms2（原位于普通小麦4D染色体短臂距着丝点31．2cM的显性雄性不育核基因）。重新异回普通小麦染色体组中，所获得携带易组Ms2基因的新型太谷核不育小麦其显性雄性不育特性表达正常，且雄性不育株的雌性可育机制正常，对不育株幼穗花粉母细胞减数分型期染色体构型的观察可见其为整倍体（2n=42)，尚未发现回归普通小麦的易组太谷核不育与原位 的太谷核不育基因有不同的表型。采用系统的标志基因测交法对回归普通小麦的易组太谷不育基因进行测交定位，发现易组Ms2基因与普通小麦显性秆标志基因Rht3连锁，从而将其定位于普通小麦4B 色体虎Rht3基因9.7cM处，新位点被命名为Ms2（4BS），对Ms2基因在六倍体小黑麦与原太谷核不育小麦远缘杂交中位时的走向，普通小麦4A与4B染色体的互换更名以及Ms2（4BS）新位点的开发利用进行了讨论，认为异源多倍体生物核基因的组间易位倾向于从供体染色体向进化亲缘关系较密切，且染色体序数与染色体臂相同的部分同源染色体易位；1988年第7届国际小麦遗传学会对普通小麦4A与4B染色体的互换更名是正确的；Ms2（4BS）作为一个新型的遗传标记，作为小麦族内所有携带B染色体组的物种的育种工具和在拓建各为小麦种质资源的基因库等方面均有广泛的用途。

Genetic Mapping of the Intergenomic Translocated "Taigu" Genic Sterility Gene (Ms2)

The "Taigu" genic sterility gene Ms2 located on the short arm of the 4D chromosome of common wheat (AABBDD) originally incorporated into hexoploid triticale (AABBRR) and durum wheat (AABB) through intergenomic translocation in distant hybridization was introduced back into the genomes of common wheat. The dominant male sterility was expressed normally in the new "Taigu" genic sterile wheat carrying the intergenomically translocated Ms2 , and the female fertility mechanism in its male sterile plants was normal as well. Observation of the chromosome configuration at meiosis of pollen mother cells (PMC) of the young ears of the sterile plants showed that they were euploid plants (2n=42). No configurations different from those of the "Taigu" genic sterility gene located at the original locus were noticed of the Ms2 intergenomically translocated back into the common wheat. In systematic test crosses with marker genes the intergenomically translocatedgene Ms2 was found to be linked with the dominant dwarf marker in common wheat Rht3 and, consequently, remapped and located on the short arm of the 4B chromosome of common wheat with a distance of 9.7 cM from Rht3 . The new locus was disignated as Ms2 (4BS). Discussions are given of the fate of Ms2 during translocation in the hexoploid triticale, the exchange of the names for 4A and 4B chromosomes in common wheat and the possible expoitation of the new locus Ms2 (4BS), and the following speculations are made: (a) In genic genes of allopolyploid organisms the donor chromosomes tend to be intergenomically translocated to their phylologically and evolutionarily close chromosomes with the same order number and the same arm; (b) it is confirmed that the 7 th International Conference of Wheat Genetics was right to exchange the names between chromosomes 4A and 4B of common wheat in 1988; and (c) as a new genetic marker and a breeding tool for all the chromosome B carrying species in the tribe of Triticeae, Ms2 (4BS) may have wide application in building and expanding the gene pool of germplasm resources of various species of wheat.