中文摘要：

为建立球花石斛的DNA分子标记鉴别方法，本文根据测定及GenBank上登录的109种共计164个石斛样本的rDNAITS序列，设计了特异性鉴别引物QH—JB1和QH—JB2，并对球花石斛进行了位点特异性PCR鉴别研究。结果表明，当复性条件为63．5℃，1min时，只有球花石斛的模板DNA能被扩增出约300bp的阳性扩增带，而其他种石斛均为阴性。证明用本法鉴别球花石斛简便、省时，也适用于干燥球花石斛药材的鉴别，具有广泛的应用前景。

英文摘要：

The aim of this study was to establish a diagnostic PCR method for authentication of D. thyrsiflorum Rchb. f. Based on rDNA ITS sequences of the 164 samples from 109 Dendrobium species sequenced and quoted from GenBank, the allele-specific diagnostic primers QH-JB1 and QH-JB2 for authentication were designed. Using the primers, diagnostic PCR was performed with the total DNA of D. thyrsiflorum Rchb. f. and other D. species as templates to establish the positive PCR condition for D. thyrsiflorum Rchb. f. A DNA fragment about 300 bp was amplified from D. thyrsiflorum Rchb. f. with anneal temperature at 63.5℃ and anneal time at ! min, whereas no other DNA fragment was amplified from the rest D. species. The allele-specific diagnostic PCR was proved to be a simple and quick identification technique, suitable for the authentication of both fresh and dried materials of D. thyrsiflorum Rchb. f.