Diallelic Nuclear Microsatellites for Diversity and Population Analyses of the Allotetraploid Creeping Bentgrass ( Agrostis stolonifera )

Nine diallelic nuclear microsatellite loci were characterized and developed as markers for analyses of diversity and population biology in creeping bentgrass, Agrostis stolonifera L. (2n = 4x = 28, A 2 A 2 A 3 A 3 ). They may also help with identification of bentgrass germplasm resources. Polymorphic loci were isolated from genomic libraries from A. stolonifera and from A. transcaspica Litv. (2n = 2x = 14, putative A 3 A 3 ). Markers were characterized in 87 A. stolonifera individuals from six distinct population sources. Analysis of molecular variance indicated significant variation between crop and wild groups. Highly significant variation was observed among and within the six populations. Bayesian analyses with STRUCTURE resolved crop from wild genotypes and assigned individuals to clusters that corresponded to their sources, in agreement with principal coordinates analysis results. The markers also correctly identified intraspecific creeping bentgrass F 1 hybrids. Cross-species analyses were conducted on sexually compatible relatives A. gigantea R. (2n = 6x = 42, A 1 A 1 A 2 A 2 A 3 A 3 ), A. capillaris L. (2n = 4x = 28, A 1 A 1 A 2 A 2 ), and A. canina L. (2n = 2x = 14, A 1 A 1 or possibly A 2 A 2 ), plus A. transcaspica. Seven markers were diallelic in A. gigantea. Six of these markers were also diallelic in A. transcaspica, but not other species, suggesting that these loci are A 3 genome specific. Results also support the hypothesis that A. transcaspica is the source of the A 3 subgenome found in A. stolonifera and A. gigantea.