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通过四倍体二粒小麦和节节麦杂交而获得的人工合成六倍体小麦,含有丰富的普通小麦品种改良有益基因,作为拓宽普通栽培小麦性状和新品种改良的新的种质资源已广泛应用于普通小麦的遗传改良实践中。利用分布于小麦A、B、D基因组21条染色体、28个不同染色体臂上的37对微卫星引物,对人工合成六倍体小麦与四川成都平原普通栽培小麦主栽品种杂交、回交经多代选择而形成的117份人工合成六倍体小麦衍生后代高代群体系(其中川麦38、川麦42、川麦43和川麦47为审定品种)进行了DNA分子水平上的分析,共检测到256个等位基因变异,平均每个SSR标记位点检测到6.92个等位变异基因。每个SSR位点等位基因变异数在1~14个,变异幅度较大,表明SSR分子标记在人工合成六倍体小麦中表现出高水平的遗传变异。A,B,D基因组中,D基因组表现出的多态性信息含量最低,为0.427 6,B基因组次之,为0.534 6,A基因组最高,达到0.614 5(A>B>D)。辛普森指数比较的结果也反映出相同的变化趋势,A基因组最高,为1.187 4,B基因组次之,为1.081,D基因组最小,为0.804 6(A>B>D)。综合多态性信息含量和辛普森指数的估值,表明这一批人工合成六倍体小麦后代衍生高代群体接受的遗传基因既来自人工合成六倍体小麦,又来自普通栽培小麦,显示杂合度类型丰富,具有较高的遗传差异。根据获得的等位基因变异片断的分布情况进行UPGMA聚类,发现A,B,D基因组基因型间的遗传相似系数较低,A,B,D三基因组37个SSR标记位点所得平均遗传相似系数为0.472 1,A基因组平均遗传相似系数为0.379 7,B基因组平均遗传相似系数为0.462 7,D基因组上平均遗传相似系数为0.581 5,反映出人工合成六倍体小麦后代衍生群体材料的遗传多样性处于较高水平。本研究结果证明利用人工合成六倍体小麦所具有的普通小麦野生近缘种中的基因库改良现代小麦,丰富其遗传基础,减少其生物和非生物胁迫的脆弱性,是一条行之有效的途径。
Synthetic hexaploid wheat, which is obtained by crossing tetraploid wheat and nodular wheat, is rich in common wheat cultivars for improving beneficial genes and has been widely used as a new germplasm resource for broadening the traits and new varieties of common cultivated wheat Used in common wheat genetic improvement practices. 37 pairs of microsatellite primers distributed on 21 chromosomes of A, B and D genomes of wheat and 28 different chromosomal arms were used to hybridize the cultivated hexaploid wheat and the cultivated common wheat cultivars in Chengdu Plain, A total of 117 high-generation hexaploid wheat-derived progenies (including Chuanmai 38, Chuanmai 42, Chuanmai 43 and Chuanmai 47) were selected and sequenced to analyze the molecular level of DNA. 256 alleles were detected. On average, 6.92 alleles per SSR marker were detected. The number of alleles per SSR locus ranged from 1 to 14 with large variation, indicating that SSR markers showed high genetic variation in synthetic hexaploid wheat. In the genomes of A, B and D, the D genome showed the lowest polymorphic information content of 0.427 6, followed by the B genome of 0.534 6 and the highest A genome of 0.614 5 (A> B> D). The Simpson index comparison also showed the same trend. The highest A genome was 1.187 4, the second was B genome 1.081, and the lowest was D genome 0.804 6 (A> B> D). The integrated polymorphism information content and Simpson index estimation showed that the genetic populations of these high-generation derived offspring of synthetic hexaploid wheat came from both synthetic hexaploid wheat and common cultivated wheat and showed heterozygosity Rich in type, with high genetic diversity. UPGMA clustering based on the distribution of the obtained allelic variation fragments found that the genetic similarity coefficients of genotypes of A, B and D genotypes were low, and the average genetic similarity of 37 SSR loci in A, B and D genomes was similar Coefficient of 0.472 1, the average genetic similarity coefficient of A genome was 0.379 7, the average genetic similarity coefficient of B genome was 0.462 7, and the average genetic similarity coefficient of D genome was 0.581 5, which reflected the inheritance of synthetic hexaploid wheat derived population Diversity is at a high level. The results of this study demonstrate that it is an effective way to improve modern wheat by enriching its genetic base and reducing the vulnerability of its biotic and abiotic stress by utilizing the gene bank of common wheat wild relatives of synthetic hexaploid wheat way.