人工合成双二倍体小麦过程中遗传变异的AFLP分析

为了给人工合成双二倍体小麦育种中亲本的选配提供基因表达水平的依据,通过AFLP方法对人工合成双二倍体小麦Am1、Am5、Am6及其亲本基因组DNA进行了遗传变异分析。结果表明,亲本间遗传差异越小,亲本与子代间DNA片段的遗传比率越高。母本Ps5与父本Y95之间四、二倍体差异带率最小,为35.2%,它们与后代Am5三者之间公共带率最大,为47.9%;后代双二倍体倾向于缺失二倍体亲本的遗传信息。Am1、Am5和Am6缺失二倍体亲本中DNA扩增片段的比率高,分别为71.0%、82.8%和90.0%,分别是缺失四倍体亲本的2.4、4.8和9.0倍;亲本间的遗传差异与后代中出现特异DNA片段的概率没有直接相关性。Am1中出现特异DNA片段的比率最高(6.2%),但是其亲本间遗传差异介于其他两组试验材料之间。

Analysis of Genetic Changes in Newly Synthesized Wheat Amphiploids Using AFLP Markers

A total of 178 pairs of AFLP primer combinations were chosen to amplify the DNA of three amphidiploid wheats (AABBDD) and their diploid (DD)/tetraploid (AABB) parents. Rapid genetic changes in Am1, Am5, Am6, and their parents were analysed by DNA AFLP technique. It is the monomorphic bands present in the amphidiploids and their parents, indicating the existence of DD and AABB genomes in the synthesized amphidiploid wheats and the genetic relation of the synthesized amphidiploid wheats and their parents. The genetic difference between parents is the smaller and the percentage of monomorphic bands is the higher. In cross Ps5×Y95, there was the lowest percentage of polymorphic bands (35.2%) between parents compared with the highest percentage of monomorphic bands (47.9%).Sequence deletion occurred in amphiploids, the loci of which were mainly from their diploid male parent. The bands that had disappeared in Am1, Am5 and Am6 originated from their diploid parents and the percentage of bands were 71.0%, 82.8% and 90.0% respectively, which were 2.4 fold, 4.8 fold and 9.0 fold higer than the elimination rates from their tetraploid parents. There are a few new unique bands in the amphidiploid wheats and the appearance of new bands could be determined irrespective of the polymorphism of the parents. The percentage of new bands that appeared in Am1 was the highest 6.2% and the genetic difference between parents of Am1 was greater than that between parents of Am5 but smaller than that between parents of Am6.