Morphological and molecular genetic variations of some taxa of genus <i>Acacia</i> and their taxonomic significance¹

A resemble in Acacia s.l. spp. morphology causes a great confusion about its identification. So, the current study's objectives are using morphological and molecular traits for accurate identification of Acacia s.l. taxa, assess the discrimination of the newly proposed genera of Vachellia and Senegalia and detect the genetic variations between studied taxa. The morphological characters of 24 taxa of genus Acacia s.l. were investigated with emphasis on seeds. DNA fingerprint and the genetic relationships among the studied taxa were investigated by using 10 (RAPD) and 10 (ISSR) markers that showed a relatively equal polymorphism (about 15%). RAPD marker generated a total of 395 fragments of which 64 bands were polymorphic, while ISSR primers generated a total of 314 fragments, 46 of them were polymorphic. The generated dendrogram that based on 893 traits divided the studied taxa of Acacia s.l. into two major groups; Acacia s.s. group and Vachellia group that containing Senegalia taxa. The complementary use of morphological and molecular data gave an accurate characterization and clear the genetic variation between studied taxa of Acacia.广义金合欢（Acacia s.l.）类群的形态相似性，导致其鉴定工作极易产生混淆。因此本研究的目标为：通过形态学与分子性状对广义金合欢（Acacia s.l.）类群进行精准鉴定，评估新提出的阿拉伯胶树属（Vachellia）与塞内加尔金合欢属（Senegalia）的分类鉴别能力，并检测供试类群间的遗传变异。本研究对24个广义金合欢（Acacia s.l.）类群的形态性状进行了调查，重点关注种子相关性状。本研究采用10条随机扩增多态性DNA（Random Amplified Polymorphic DNA, RAPD）引物与10条简单序列重复区间扩增多态性（Inter-Simple Sequence Repeat, ISSR）引物，对供试类群的DNA指纹图谱及遗传关系进行分析；两类标记的多态性比例相近，均约为15%。其中RAPD标记共扩增得到395条片段，其中64条为多态性条带；ISSR引物共扩增得到314条片段，其中46条为多态性条带。基于893个性状构建的系统聚类树将供试广义金合欢（Acacia s.l.）类群划分为两大主要类群：狭义金合欢类群（Acacia s.s.），以及包含塞内加尔金合欢属（Senegalia）类群的阿拉伯胶树属（Vachellia）类群。形态学与分子数据的联合应用，实现了供试金合欢类群的精准表征，并明确了其遗传差异。