从CIMMYT引进的人工合成六倍体小麦D染色体组微卫星分子标记的遗传差异

采用微卫星（SSR）分子标记技术，选用23个D染色体组特异性引的对来自CIMMYT的26份人工合成六倍体小麦D染色体组的遗传多样性进行了分析。研究发现，26份材料在D染色体组上存在丰富的等位基因变异（92个），平均每个基因座为4个。遗传距离计算结果也显示，26份材料D染色体组之间具有较大的遗传差异，平均遗传距离高达0．4955。因此，人工合成六倍体小麦D染色体组中存在丰富的遗传多样性，可以作为拓宽普通小麦遗传基础的新的遗传变异来源。研究还发现，由同一个粗山羊草基因型与不同硬粒小麦杂交合成的人工合成六倍体小麦（如合成种17和18）在所用检测的23个基因座中有3个存在差异，说明小麦在多倍化后，供体基因组在重复序列区域会发生遗传分化。

Genetic Diversity of D-genome Revealed by SSR Markers in Synthesized Hexaploid Wheat Introduced from CIMMYT

Simple sequence repeat (SSR) molecular marker was used to measure the genetic diversity of D genome in 26 synthesized hexaploid wheat (AABBDD) introduced from CIMMYT. Twenty three D genome specific SSR primers were selected for PCR amplification, among which 22 primers can detect polymorphism.A total of 92 alleles were identified at 23 loci using the above SSR primers, with an average of 4 alleles per locus. The 92 alleles were used to calculate Nei's similarity index ( GS ) and the genetic distance ( GD ). It was also found that the mean genetic distance between 26 synthesized hexaploid wheat was 0.4955, which was obviously high. From the above results, it can be indicated that the genetic variation of D genome in synthesized hexaploid wheat was abundant and could be used to improve the genetic diversity in wheat breeding. Interestingly, synthesized hexaploid wheat 17 and 18 shared the same D genome donor, but three of 23 detected SSR loci were polymorphic between the two materials. Therefore, during the period of allopolyploidization, there was genetic differentiation in repeat region of donor genome.