中文摘要：

【目的】为了构建火龙果芽变种质的DNA指纹图谱,并揭示种质间的遗传关系,【方法】以贵州近几年选育的一些优良火龙果种质为试材,采用ISSR标记技术和NTSYS 2.01软件对这些新种质及其原始品种进行分析。【结果】利用筛选出的52条引物进行PCR扩增,共扩增出364个清晰、重复性好的标记,其中215个（60%）为多态性标记。M08、845和881等3个引物扩增出的标记能将22份种质区分开来。采用NTSYS 2.01软件计算,供试种质间的相似性系数为0.70~0.96,平均0.81,其中红肉种质间平均值为0.82,白肉为0.89。UPGMA聚类分析显示,在相似系数0.9处可将供试材料分为11类,其中7份分别各自聚类（红肉占86%）。【结论】火龙果体细胞变异率较高,且红肉品种高于白肉品种,通过芽变选种能有效地实现遗传改良。

英文摘要：

[Objective]The objective of the stuety is to estimate the genetic relationships among the germplasms as well as to construct DNA fingerprints of dragon fruit. [Method]A total of 19 excellent lines of dragon fruit with white flesh and red flesh had been selected in Guizhou province during the past years. Currently, ISSR markers and NTSYS 2.01 were employed to unravel their genetic relationship. [Result] The results showed that a total of 364 bands were yielded from the 52 selected primers, among which 215 （60%） were polymorphic. The specific markers generated from primer M08, 845 and 881 might effectively distinguish the tested accessions, therefore, ISSR marker is accessible for fingerprinting in this crop. Computed by NTSYS 2.01, the similarity coefficients among the tested accessions were in the range of 0.70 to 0.96, and the average was 0.81. The mean similarity coefficients among the red-flesh lines and white-flesh lines were 0.82 and 0.89, respectively. The UPGMA dendrogram demonstrated that 22 germplasm could be divided into two groups （white-flesh and red-flesh types） at a cutpoint of 0.77. [Con- clusion]These data reflected that somatic variation in red-flesh line is higher than that of white-flesh for genetic improvement in this crop. occurrence of dragon fruit is fairly high, and variation line, thereby bud sport selection may be the chief way