中文摘要：

对梨属19个种共26个供试样本及两个苹果属外类群样本的叶绿体非编码区trnL-trnF和accD-psaI进行了序列分析。排列后的序列长度分别为927 bp和944 bp。两个区域组合后共有36个核苷酸替换（substitution）和11个插入/缺失（indel）。将所有indel处理为一次变异事件并编码为替换,用于简约法系统树和NeighborNet系统发育网络（phylogenetic networks）的构建。研究结果表明：indel为系统发育分析提供了可靠的信息;相比trnL-trnF,accD-psaI因进化速率较快,更适合应用于种及种以下分类水平的梨属植物系统关系研究;NeighborNet系统发育网络表明系统树上部分较低的分支支持率由冲突的信息引起,其余则由信息位点不足引起。此外结果还揭示了可疑种间杂交种的母系祖先。

英文摘要：

The two non-coding chloroplast regions,trnL-trnF and accD-psaI of 26 accessions from 19 Pyrus L.species and two outgroup accessions from Malus Mill.were sequenced.Aligned lengths of these two regions were 927 bp and 944 bp,respectively.A total of 36 substitutions and 11 indels were obtained in the combined data.All of the indels were treated as single mutation events and coded as substitutions manually when conducting maximum parsimony and Neighbor Ne（t NN）analyses.Our results showed that the indels in these two cpDNA regions were reliable phylogenetic characters and increased phylogenetic resolution;Compared with trnL-trnF,accD-psaI evolves quicker,providing more information for the discovery of inter-and intra-specific relationships in Pyrus.The NN split network indicated that the poor resolution in the phylogenetic tree was partly caused by conflicting signals or by lack of sufficient informative site.In addition,maternal lineages of putative inter-specific hybrids were revealed.