Development of a genetic system to introduce alien useful genes into common wheat and to determine their loci

最近，Endo(1999)发现来自与小麦相关的野生物种的某些基因或染色体会在普通小麦中诱发高频的染色体结构突变，并建立了诱导染色体重排的遗传系统。本研究旨在利用该遗传系统建立黑麦染色体的缺失和易位系，为小麦的遗传育种提供参考。经过两年的研究，我们取得了以下成果：1)获得了1R染色体发生染色体突变的小麦品系，2)建立了1R染色体结构变化的检测方法。1)首先，我们将1R染色体替代1B染色体的小麦品种与三联山羊草的3C染色体附加系杂交，筛选出染色体组成为2n=43(20“+1”1R+1‘3C)的衍生品系，并进一步筛选出2n=44(20“+1”1R+1“3C”)的衍生植株。用2n=44株与1R/1B代换品种杂交，将产生20“+1”1R+1‘3C的杂交后代，这些后代携带染色体突变，涉及1R染色体上的突变。利用这些小麦品系，我们将能够进行大规模的1R结构变化的筛选。对于2)，我们证明了C显带是检测1R末端缺失的一种有效技术，而原位杂交可以识别与小麦染色体易位有关的黑麦片段。此外，我们建立了一种基于PCR的方法来检测位于1R染色体卫星上的种子贮藏蛋白Secalin的基因。通过使用这些细胞遗传学技术，我们希望能够有效地识别涉及1R染色体的结构变化。

Recently, Endo (1999) found that certain genes or chromosomes derived from wild species related to wheat induce chromosomal structural mutations in common wheat with high frequencies, and established a genetic system inducing chromosomal rearrangements. The present study aimed at generating deletion and translocation lines of a rye chromosome, which would be useful for the genetics and breeding of wheat, by applying the genetic system. After the two-year research we have achieved 1) the production of wheat lines with rye chromosome 1R in which chromosomal mutations occur and 2) the establishment of detection methods of structural changes involving chromosome 1R.As to 1), first, we crossed a wheat cultivar with a substitution of chromosome 1R for wheat chromosome 1B to an addition line of wheat with 3C chromosome of Aegilops triuncialis, and selected derivatives with a chromosome constitution, 2n=43 (20"+1""1R+1'3C) : Chromosome mutations are expected to occur in the progeny. Further, we selected derivative plants with 2n=44 (20"+1"1R+1"3C). Crosses between 2n=44 plants and the 1R/1B substitution cultivar would yield hybrids (20"+1"1R+1'3C) that would produce progeny carrying chromosomal mutations, involving those in chromosome 1R.Using these wheat lines, we will be able to conduct the screening of 1R structural changes in a large scale. As to 2), we demonstrated that C-banding is an effective technique to detect 1R terminal deletions, and that in situ hybridization can identify the rye segments involved in translocation with wheat chromosomes. Further, we established a PCR-based method to detect a gene for secalin, a seed storage protein, which is located on the satellite of chromosome 1R.By using these cytogenetical techniques we expect to be able to identify effectively structural changes involving chromosome 1R.