Genetic analysis in native grasses of genus paspalum using isozyme and RAPDdata

Abstract

Among the Paspalum genus, the Dilatata group is very important for the sub-tropical region because ofits value as a forage grass and wide distribution in the region. This group has four species and seven biotypes. Different levels of ploidy and reproductive performance were studied. By using isoenzymatic markers and RAPDs, the genetic diversity and the phylogenetic relationships of 23 different species accesions were examined. 25 putative loci coded by 6 isoenzymes were detected, 21 of which were polymorphic at the interespecific level and only 4 were variable at the intraspecific level. 224 RAPD fragments were obtained with 24 random «primers» of 1O bp each. At the interespecific level, 98.5% of these fragments were polymorphic whereas among the intraspecific level, this amount was 72.3%. The phylogenetic analysis using the data obtained by the two tecniques were related to ploidy level and evolutionary origin. RAPD data were more segregating power than isoenzymes among species with same ploidy and in intraspecific analysis. Complete congruencia has not been found between isozyme and RAPD data sets. The use oftwo techniques, both isoenzymes and RAPDs as well, gave more information not only on the genetic diversity but also on the relatioships withing and among grass species.