Classification of Kentucky Bluegrass (Poa pratensis L.) Cultivars and Accessions Using SSR Markers.

Kentucky bluegrass (Poa pratensis L.) is an important facultative apomictic temperate perennial grass species utilized for both forage and cultivated turf.  Through apomixis, this species is able to propagate diverse and odd ploidy levels, resulting in many genetically distinct phenotypes.  A wide range of diverse cultivars and accessions of Kentucky bluegrass have been previously characterized based on common turf performance or morphological characteristics, as well as by random amplified polymorphic DNA (RAPD) markers.  The objectives of the current study were to genotype 265 Kentucky bluegrass cultivars, experimental selections, collections, and hybrids using microsatellite (SSR) markers, and compare the results with the original Kentucky bluegrass classification system.  All cultivars, experimental selections, collections, and hybrids were uniquely identified with the current set of SSR markers.  Genetic relationships of individuals as assessed by SSR markers closely matched known pedigrees. The current set of SSR markers can be used to rapidly genotype and assign new cultivars/accessions to Kentucky bluegrass classification types and assess genetic relatedness among individuals, and should be considered for use in a Kentucky bluegrass Plant Variety Protection program.