【摘要】 在染色体工程创造小麦新种质研究中 ,由于小麦染色体 5B长臂上具有控制部分同源染色体联会的显性基因Ph1,使外源优良基因难以通过染色体配对、交换实现基因重组。ph1b基因具有强烈促进小麦部分同源染色体配对作用。作者利用 ph1b突变体直接与簇毛麦进行远源杂交 ,探索利用 ph1b基因对簇毛麦遗传物质直接遗传转移的可能性。研究结果显示 ,经人工授粉和幼胚培养获得了普通小麦“中国春”CS及其ph1b突变体CSph1b与簇毛麦 (Haynaldiavillosa)的属间杂种F1,杂交结实率分别为 6 .6 7%和 6 .2 5%。F1植株的体细胞染色体数 2n =2 8,育性极差 ,自交不结实。F1植株花粉母细胞 (PMC)减数分裂中期Ⅰ染色体行为观察发现 :“CS×H .villosa”F1平均每PMC仅有 1.6 1条染色体形成二价体和三价体 ,平均构型为 2n =2 8=2 6 .39Ⅰ +0 .79Ⅱ +0 .0 0 7Ⅲ ,染色体交叉数 (Xta)为 0 .84 ;“CSph1b×H .villosa”F1每PMC中有 14 4 5条染色体发生联会 ,形成二价体和多价体平均构型为 2n =2 8=13.55Ⅰ +5.95Ⅱ +0 .55Ⅲ +0 .2 2Ⅳ ,染色体交叉数为 9.72 ,其中 56 %以上的PMC具有 1～ 4个多价体 (三价体、四价体 )。F1花粉母细胞FISH观察表明 :“CS×H .villosa”F1联会染色体均为小麦染色体 (W W ) ,在“CSph1b×H .villosa”F1中更多还原

【Abstract】 Chromosome pairing was analysed in F 1 hybrids of Triticum aestivum ‘Chinese Spring’(CS) and its ph1b mutant ( CS ph1b) with Dasypyrum villosum. On the average, 1.61 chromosomes per cell could pair in the hybrid CS× D.villosum , but 14.43 chromosomes per cell paired in the F 1 hybrids CSph1b× D.villosum. Genomic fluorescent in situ hybridization (GISH) revealed that three types of homoelogous associations between wheat (W) and D.villosum (D): W D, D W W and D W D in PMCs of ‘CSph1b× D.villosum ’ F 1 hybrid, and only one type, W W in ‘CS× D.villosum ’ F 1 hybrids. Both F 1 hybrids were self sterile. The seed set of the backcross of ‘CS× D.villosum ’ with CS was 6.67% and that of ‘CS ph1b× D.villosum ’ with CS or CS ph1b was only 0.45%. The chromosome number of BC 1 plants varied from 48 to 72. Translocations of chromosome segments or entire arms between wheat and D.villosum chromosomes were detected by GISH in the BC 1 plants from the backcross of ‘CSph1b× D.villosum ’ with CSph1b.更多还原