Genetic diversity among Paspalum L. species (Poaceae) belonging to the Notata and Linearia groups based on restriction fragment length polymorphism analyses.

A taxonomic study of Paspalum L. was carried out using a genetic diversity approach. Thirty accessions representing twenty one different species from the Notata and Linearia groups of Paspalum were studied using restriction fragment length polymorphism analysis of the amplified ITS ribosomal DNA (rDNA) and from the psbA-trnH of the chloroplast genome (cpDNA). The combined analysis of the internal transcribed spacer (ITS) and the chloroplast spacer region between the psbA and trnH genes identified genetic polymorphisms. A distance analysis of the molecular data generated a dendrogram which showed the relationships of the two informal groups of Paspalum studied here. Although the distribution of species in the dendrogram was found to be roughly in agreement with previous works based on morphological and cytological data, the results obtained reveal the current artificiality in Paspalum taxonomy. Based on molecular data, a new circumscription of the Notata and Linearia groups is proposed here in order to provide a more accurate delimitation of these groups and contribute to the taxonomy of Paspalum. This study, although preliminary, reveals the potential utility of such a molecular approach for clarifying the taxonomy of closely related taxa.