Abstract:

The genome constitutions of six types of partial amphiploid derived from Triticum aestivum L. ×Leymus mollis (Trin.) Hara, octoploid Tritileymus were analyzed by fluorescence in situ hybridization. The results indicated that the chromosome numbers of the six octoploid Tritileymus were all 2n=56 in somatic cells. The in situ hybridization using L. mollis (JJNN) genomic DNA as probe showed that five octoploid Tritileymus, M842-4, M842-8, M842-12, M842-13 and M842-16 possessed 14 chromosomes of L.mollis. Their chromosome constitutions could be depicted 2n=56=42Ta＋14Lm (Ta = Triticum aestivum chromosome, Lm = L. mollis chromosome). The other one, M842-10 had 12 L. mollis chromosomes and its chromosome constitution should be expressed 2n=56=44Ta＋12Lm. Using Psathyrostachys juncea (Fisch.) Nevski (NN) genomic DNA as probe, the in situ hybridization results in five octoploid Tritileymus, M842-4, M842-8, M842-10, M842-12 and M842-16 were all the same as that of using the L. mollis genomic DNA as probe. And in M842-13, fourteen chromosomes showed weaker hybridization signals; it was similar to that of the octoploid JJ8x with genomes AABBDDJJ , an amphiploid of Triticum aestivum and Agropyron junceum (L.) Beauv. (JJ). According to the above results, the genome formulas of the six octoploid Tritileymus could be deduced as follows: The M842-4, M842-8, M842-12 and M842-16 had the same genome formula of AABBDDNN ; the M842-10 had AABBDDNN ＋2Ta-2Lm (N); and the M842-13 had AABBDDJJ . The values of the octoploid Tritileymus for wheat variety improvement, the variations of L. mollis chromosome number in the octoploid Tritileymus and its probable mechanism were discussed.

八倍体小滨麦染色体组构成的分子细胞遗传学研究
王献平¹  傅杰² 张相岐^1*  景建康¹  文玉香¹

（1. 中国科学院遗传研究所植物细胞与染色体工程国家重点实验室，北京100101；
2. 西北农林科技大学，陕西杨陵712100）

摘要：应用基因组荧光原位杂交技术对 6种类型的八倍体小滨麦 (octoploid Tritileymus)的染色体组构成进行了分子细胞遗传学分析。结果表明 ,6种八倍体小滨麦的体细胞染色体数目均为 2n =5 6。用滨麦 (Leymusmollis (Trin .)Hara) (染色体组为JJNN)DNA作探针进行原位杂交时 ,M842-4、M842-8、M842-12、M842-13和M842-16等 5种类型八倍体小滨麦的体细胞中都有 14条滨麦染色体 ,其染色体组成为 2n =5 6 =42Ta +14Lm (Ta =小麦染色体 ,Lm =滨麦染色体 )。M842-10中只有 12条滨麦染色体 ,其染色体组成为 2n =5 6 =44Ta +12Lm。用新麦草 (Psathyrostachysjuncea (Fisch .)Nevski) (染色体组为NN)DNA作探针进行原位杂交时 ,M842-4、M842-8、M842-10、M842-12和M842-16的结果与用滨麦DNA作探针的原位杂交结果相同。而M842-13只在 14条染色体上显示较弱的杂交信号 ,与小麦(TriticumaestivumL .)_灯芯偃麦草 (Agropyronjunceum (L .)Beauv .)双二倍体 (染色体组为AABBDDJJ)的原位杂交结果相似。由此推断 ,M842-4、M842-8、M842-12和M842_16的染色体组构成为AABBDDNN ,M842_10的染色体组构成为AABBDDNN +2Ta - 2Lm (N) ,而M842-13的染色体组构成为AABBDDJJ。还对八倍体小滨麦的应用价值和八倍体小滨麦中滨麦染色体的数目变异及其可能的机制进行了讨论。

关键词： 八倍体小滨麦；荧光原位杂交；染色体组构成

Key words: octoploid Tritileymus, fluorescence in situ hybridization, genome constitution