我国的杜鹃属有毒植物约在60种以上，如羊踯躅等药用植物具有强毒付作用，而目前杜娟属的分类十分复杂。DNA barcoding技术是一种新的物种鉴定技术，COI序列已成功应用于动物的鉴定，但是目前国际上还没有找到一个通用序列能鉴定所有植物物种。本文对杜娟属257个物种ITS、ITS2、matK、PsbA-trnH序列比较，运用Wilcoxon秩和检验比较不同序列的变异性，然后用Taxon DNA软件评估这四个序列的barcoding gap。筛选适合于杜娟属的DNA条形码序列。分析结果表明：matK和psbA-trnH并不适合于杜娟属的DNA barcoding鉴定。ITS2和ITS序列都可以有效的对杜娟属植物进行DNA barcoding鉴定，但ITS在物种中的扩增效率较低，因此推荐将ITS2序列作为一个潜在的杜娟属植物DNA barcoding鉴定候选序列。

In China, there are more than sixty types of toxic plants Rhododendron, including Rhododendron molle (Blum) G. Don, a traditional medicine. So far no techniques or methods have been found to effectively identify all the Rhododendron plants. DNA barcoding is a technique to identify species using DNA sequences from a small fragment of the genome. DNA barcoding, such as COI sequence, has been used to identify animal species. Unfortunately, there has been no universally accepted barcode system applicable to plants. This study compared four potential barcodes (ITS, ITS2, matk, and psbA-trnH) of 257species of Rhododendron. Wilcoxon signed rank tests were used to analyze the variability of sequences, and Taxon DNA was used to estimate the barcoding gap, so as to screen out the right barcodes for identifying the species of Rhododendron. Screening results showed that neither matk nor psbA-trnH could be used to identify Rhododendron on its own. On the contrary, both ITS and ITS2 were proved effective for the function. Due to the low success rate of PCR for ITS, ITS2 sequence can be taken as a potential barcode for identifying the species of Rhododendron.

国家科技部国际合作基金（2007DFA30990）：中药材DNA 条形码鉴定研究负责人：陈士林。