Kentucky bluegrass (Poa pratensis L.) is an important facultative apomictic temperate perennial grass species used 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 pedigree, common turf performance, and morphological characteristics to create a kentucky bluegrass cultivar classification system. The objectives of the current study were to assess the amount of genetic divergence among kentucky bluegrass cultivars, experimental selections, and plant collections and revise/update the original pedigree, turf performance, and morphological characteristics kentucky bluegrass classification system using recently described kentucky bluegrass microsatellite [simple sequence repeat (SSR)] markers. In this study, 247 kentucky bluegrass cultivars, experimental selections, and collections were genotyped using 25 SSR markers. SSR markers showed a strong correlation between genetic relatedness as assessed by molecular markers and the original kentucky bluegrass classification system and also provided justification for a revision/update of the classification system. Traditional classification types that were supported by the current SSR analysis include BVMG, Compact, Compact-America, Julia, Mid-Atlantic, Midnight, and Shamrock types. Newly proposed classification types included Cynthia, Jefferson/Washington, Limousine, P-105, Sydsport, and three Eurasian types. The majority of cultivars, experimental selections, and collections 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.

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Kentucky bluegrass (Poa pratensis L.) is an important perennial forage and amenity turfgrass species used throughout temperate regions in North America and Europe. Kentucky bluegrass cultivars and accessions exhibit a wide range of ploidy levels, morphological traits, turfgrass quality characteristics, and tolerances to both biotic and abiotic stresses. As such, cultivar classification systems have been developed to categorize Kentucky bluegrass cultivars and accessions on the basis of pedigree, turf performance, morphological traits, and genetic relatedness (DNA markers). The objectives of the current study were to assess the genetic diversity among and within Kentucky bluegrass entries using simple sequence repeat (SSR) markers, and to categorize new germplasm in the Kentucky bluegrass classification system. In this study, 21 SSR markers were used to genotype eight individuals from each of 144 bluegrass cultivars and accessions (1152 total samples). The SSR markers successfully categorized all entries into distinct classification groups and provided justification for a partial revision to the previous DNA marker‐based classification system. The majority of cultivars and accessions were uniquely identified with the current set of SSR markers, and SSR marker‐based genetic relationships of individuals within classification types showed agreement with breeding history records. Over 60 new Kentucky bluegrass National Turfgrass Evaluation Program entries were placed into updated classification groups, and the SSR markers used in this study can be used in the future to genotype and assign new cultivars and accessions into Kentucky bluegrass classification types and assess the genetic relatedness among entries.

Microsatellite markers are potentially valuable molecular genetic markers for conservation ecology, paternity testing, pedigree reconstruction, population genetics, and linkage mapping. Traditional methods for the development of microsatellite markers can be time‐consuming, laborious, and expensive. Next‐generation sequencing (NGS) is a more recent and promising approach to microsatellite marker development. Perennial ryegrass (Lolium perenne L.) is an important turfgrass species with a limited set of publicly available microsatellite markers. Here we conducted Illumina NGS, as well as genotyping of a Lolium test population, to identify and characterize perennial ryegrass microsatellite markers. Sequencing and assembly results returned a microsatellite marker database containing 10,830 perfect di‐ and 42,718 perfect trinucleotide microsatellites with repeat unit lengths equal to or greater than six and four repeat units, respectively, as well as sufficient flanking sequence to enable polymerase chain reaction (PCR) primer design. Genotyping results from a subset of 172 di‐ and trinucleotide microsatellite markers indicated that 38.7% of these markers were polymorphic in perennial ryegrass, and 21.5% were transferable to and polymorphic in annual ryegrass (Lolium multiflorum Lam.). The thousands of expected polymorphic markers reported herein provide a significant new resource for studying Lolium genetic diversity, parentage analysis, linkage analysis, and germplasm in turf and forage breeding programs.