DIVERSITY AMONG POPULATIONS OF SWITCHGRASS BASED ON RAPD MARKERS

Information on the amount of genetic diversity in switchgrass (Panicum virgatum L.) is necessary to enhance the effectiveness of breeding pr ograms and germplasm conservation efforts. This study characterized an d assessed genetic diversity by means of RAPD markers among 14 populat ions representing upland and lowland switchgrass ecotypes. Forty-five of 128 primers produced polymorphic markers among sets of genomic DNA pooled from individual genotypes of each population. Five primers were selected to amplify a total of 91 polymorphic loci among genotypes. T he RAPD markers were scored for presence or absence of bands to genera te distance matrices for cluster analysis. Overall similarity was 65% among populations compared to 81% within populations. Blackwell and Ca ddo were the most similar populations (78%) based on RAPD markers, whe reas Alamo and Forestburg were the most divergent (53%). Cluster analy sis clearly segregated populations into two main groups (putatively ba sed on ecotype) and united individual genotypes within a population in to discrete groups within the larger clusters. Although the relationsh ip between ploidy level and ecotype remained unclear, RAPD profiles ca n be used to identify switchgrass populations and may be useful in pre dicting relationships between experimental germplasm sources and relea sed populations.