普通小麦1B／4A染色体相互易位的细胞遗传学研究

Cytogenetic Studies on a Reciprocal Translocation Between Chromosomes 1B and 4A in Common Wheat

利用Ｃ－分带技术对普通小麦品种扬麦３号的体细胞染色体进行分析，发现其１Ｂ和４Ａ染色体与普通小麦品种中国春明显不同。扬麦３号的１Ｂ长臂与中国春４Ａ长臂带型相同，而其４Ａ长臂带型又与中国春１Ｂ长臂带型一致，这一结果表明，扬麦３号的１Ｂ和４Ａ发生了相互易位，易位断裂点分别在１Ｂ的Ｌ２．２带区和４Ａ的Ｌ１．４带区，所形成的易位染色体分别命名为ＴＩＢＳ·Ｌ２．２：：４ＡＬ１．４＋ｔｅｒ和Ｔ４ＡＳ·Ｌ１．４：：ＩＢＬ２．２、ｔｅｒ。用扬麦３号与中国春１Ｂ和４Ａ的双端二体杂交，其Ｆ１分别有５２．４％和７１．７％花粉母细胞形成异型五价体，表明扬麦３号的１Ｂ和４Ａ参与易位染色体的形成，从而进一步证实Ｃ一分带鉴定的结果。

The somatic chromosomes of the wheat (Triticum aestivum L. )cultivar Yangmai No. 3 were analyzed by means of C-banding technique. It was found that the chromosome 1B of Yangmai No. 3 showed the long arm bands similar to those of 4AL in cv. Chinese Spring, whereas the long arm of the chromosome corresponding to 4A of cv. Chinese Spring had a very similar banding pattern to that of 1BL, suggesting that reciprocal translocation occurred between 1B and 4A in Yangmai No. 3. The translocation breakpoints were located at band L2. 2 in 1B and band L1. 4 in 4A. The translocated chromosomes were described as T 1BS. L2. 2:: 4AL1. 4 →ter and T4AS· L1· 4:: 1BL2. 2→ter. Crosses were made between Yangmai No. 3 and Chinese Spring double ditelosomics 1B and 4A to verify the chromosomes involved in the translocation. The F1 plants tested for 1B had a meiotic pairing configuration of 19 bivalents and a pentavalent with two telosomes attached at a frequency of 52. 4%, and this configuration also appeared in F1 plants tested for 4A at 71. 7%,indicating that chromosomes 1B and 4A were involved in the exchange,and further confirming the results from C-banding.