Genetic differentiation and relationship of populations in the Aconitum delavayi complex (Ranunculaceae) and their taxonomic implications

Abstract

The Aconitum delavayi complex consists of six climbing diploid species distributed mainly in the Hengduan Mountains of China. In order to clarify the circumscription and relationships among species within the complex, RAPD markers were employed to examine the differentiation of 18 populations representing all the six species. The PCO and cluster analyses of RAPD data indicated that the Aconitum delavayi complex comprises three different clusters. The first cluster consists exclusively of A. episcopale populations, which indicates that A. episcopale is a very distinct species, in good agreement with our previous allozyme and ITS data. The second cluster includes one A. campylorrhynchum population and all the A. henryi populations from the northern Hengduan Mountains region and its neighbor areas. The third cluster consists of the populations of A. delavayi, A. stapfianum, A. tuguancunense and A. campylorrhynchum from the southern Hengduan Mountains region. The little genetic differentiation among populations of A. stapfianum, A. delavayi and A. tuguancunense suggests that they would better be treated as a single species. The fact that A. campylorrhynchum populations appear in two different clusters demonstrates that A. campylorrhynchum comprises of two different species.