用RAPD分析麻核桃起源与分类地位

利用随机扩增多态性ＤＮＡ（ＲＡＰＤ）方法对麻核桃、核桃楸、核桃、奇异核桃和核桃×核桃楸的人工杂种进行了基因组多态性分析。选用２８个１０ｂｐ随机引物扩增出３３２个ＤＮＡ片断，片断大小在２５９ｂｐ～３０５４ｂｐ之间，其中２４３个ＤＮＡ片断呈现多态性，占总扩增片断的７３２％。依据扩增结果进行相似性系数和遗传距离分析，据此构建聚类树状图。研究结果表明：核桃楸×核桃的天然杂交是麻核桃形成的主要机制；在麻核桃形成过程中，核桃楸的遗传贡献率大于核桃；在胡桃属分类中，麻核桃应归为核桃楸组，这与传统分类学的结果一致。

ANALYSIS OF THE ORIGIN AND THE TAXONOMIC POSITION OF \%JUGLANS HOPEIENSIS\% USING RAPD MARKERS

The genomic DNA variations of \%J.hopeiensis\, J.mandshurica\, J.regia\,J.hidsiiJ.regia\% and \%J.regiaJ.mandshurica\% were analyzed using random amplified polymorphism DNA(RAPD) in the present study. Twenty\|eight decanucleotide arbitrary primers generated 332 RAPD bands with the size ranging from 259 bp to 3054 bp, 243 of these bands were polymorphic (73.2%). The similarities and genetic distances among them were analyzed with Jaccard's and Nei's methods respectively. The dendrogram based on the genetic distances supports the hypothesis that \%J.hopeiensis \%originated from the nature hybrid of \%J.regia\% and \%J.mandshurica.\% In addition, the \%J.mandshurica \%gave more genetic contribution than \%J.regia \%to the hybrid. Therefore the \%J.mandshurica\% is suggested in the \%Sect. Cardiocaryon, \%which agrees with the conventional taxonomic position.\=