引物及RAPD标记数对芥菜变种聚类分析的影响

利用ＲＡＰＤ标记对１６个芥菜变种的遗传关系进行研究，并在ＵＰＧＡ聚类分析的基础上建立了亲缘关系系统树图和利用不同的引物数和不同的ＲＡＰＤ标记数对芥菜进行聚类分析。结果表明，聚类结果基本一致。即都可将１６个芥菜变种划分为３组：Ｃ组只有茎瘤芥１个变种，Ａ组和Ｂ组的变种数则略有差异。说明少至２种引物的扩增产物（２７个ＲＡＰＤ标记）也能基本反映１６个芥菜变种间的遗传关系。但随着引物数和ＲＡＰＤ标记数的减少，１６个芥菜变种间的平均遗传距离递减，即从１９种引物、２４０个ＲＡＰＤ标记的７．３４减少到２种引物、２７个ＲＡＰＤ标记的２．３４。而遗传距离的变小，使划分芥菜变种的亲缘关系更加困难。因此，在利用ＲＡＰＤ技术研究芥菜变种间的遗传关系时，有必要保证一定数量的引物和ＲＡＰＤ标记。

AFFECTION OF DIFFERENT PRIMER NUMBERS AND RAPD MARKER NUMBERS ON CLUSTER ANALYSIS OF SIXTEEN MUSTARD VARIETIES

In this paper, RAPD markers were used to reveal the genctic relationships among sixteen mustard ( Brassica juncea Coss.) varieties. Cluster analysis was carried out with UPGA (Unweighted Pair Group Average) and Dendrogram was established based on genetic distance matrix. Dendrograms of different primer numbers and different RAPD marker numbers showed that sixteen mustard varieties were divided into three groups: A, B and C. Group C included only one varicty, Jingliujic. Varieties of Group A and Group B were slightly different. It could be concluded that as few as 217 RAPD markers amplified by two primers could reveal the genetic relationships among sixteen mustard varieties in general. But with decrease of primer numbers and RAPD marker numbers, the mean genetic distances were decreased accordingly (from 7.34 of 240 RAPD) markers amplified by 19 primers to 2.34 of 27 RAPD markers amplified by 2 primers), making it more difficult to divide the sixteen varieties of mustard. So, it is necessary to make use of a certain number of primers and RAPD markers in order to reveal as accurate as possible the genetic velationships among the sixteen varieties.