XVI International Botanical Congess

This investigation was an effort to find genetic variation in Gulf Coast populations of Phragmites australis that were shown to be genetically uniform in previous isozyme studies. Three populations were analyzed using nine 10-mer primers. A total of 24 interpretable bands created the data set. In contrast to the isozyme results, more than 50% of the RAPD loci were polymorphic. A Dice similarity matrix and a UPGMA dendogram revealed that most of the variation occurred among populations, although each of the three had some level of within-population variation. The presence of genetic variation (as revealed by RAPDs) in clonal populations has recently been observed in an apomictic fern, Dryopteris. In Dryopteris, as in Phragmites, it is seems likely that somatic mutations account for the variation present.