Phylogenetic Distances among Several Genotypes of Rebutia , Mediolobivia and Sulcorebutia (Cactaceae)

摘要

The family Cactaceae is one of the most popular, easily recognizable and morphologically distinct families of plants. In this study, we analysed 41 genotypes with taxonomic and molecular marker methods (random amplification of polymorphic DNA). The botanical classification that describe the phenotypic aspects of different characters, such as plant diameter, number of spines, length of spines, spine diameter and flower colour, was used like taxonomic method. In Rebutia species, the plant diameter varied from 2 cm ( R. atrovirens , R. mamillosa var . australis , R. violaciflora ) to 4.5 cm ( R. almeyeri ). Of the species of the genus Mediolobivia examined in this study, M. orurensis f. SE had the greatest plant diameter (3.5 cm), whereas M. steinmannii var . parvula had the smallest (10-15 mm). The species of the genus Sulcorebutia have larger plant diameters than those of the species of Rebutia and Mediolobivia . Sulcorebutia grandiflora is 7.5 cm in diameter. DNA was isolated from 41 genotypes of cacti. The average DNA yield from all the genotypes was 106.40 ng μg^-1. The DNA yield per individual ranged from 29.13 ng μg^-1 ( Sulcorebutia grandiflora ) to 352.59 ng μg^-1 ( S. rauschii WR 299). The genetic diversity was calculated with Jaccard?s index and the phylogenetic tree (dendrogram), based on a similarity matrix, was generated with a neighbour-joining programme. The dendrogram indicates the diversity of the genotypes, which are grouped into six distinctive large groups. The largest group includes species from the Mediolobivia and Rebutia genera, which clearly share a common ancestor.