title: Genetic variation and  comparison of orchardgrass (Dactylis glomerata L.) cultivars and  wild accessions as revealed by SSR markers.
abstract: Orchardgrass  is a highly variable, perennial forage grass that is cultivated throughout  temperate and subtropical regions of the world. Despite its economic  importance, the genetic relationship and distance among and within cultivars  are largely unknown but would be of great interest for breeding programs. We  investigated the molecular variation and structure of cultivar populations,  compared the level of genetic diversity among cultivars (Baoxing, Anba, Bote,  and Kaimo), subspecies (Dactylis glomerata ssp Woronowii) and  advanced breeding line (YA02-116) to determine whether there is still  sufficient genetic diversity within presently used cultivars for future  breeding progress in China. Twenty individuals were analyzed from each of six  accessions using SSR markers; 114 easily scored bands were generated from 15  SSR primer pairs, with an average of 7.6 alleles per locus. The polymorphic  rate was 100% among the 120 individuals, reflecting a high degree of genetic  diversity. Among the six accessions, the highest genetic diversity was observed  in Kaimo (H = 0.2518; I = 0.3916; P = 87.3%) and 02-116 had a lower level of  genetic diversity (H = 0.1806; I = 0.2788; P = 58.73%) compared with other  cultivars tested. An of molecular variance revealed a much larger genetic  variation within accessions (65%) than between them (35%). This observation  suggests that these cultivars have potential for providing rich genetic  resource for further breeding program. Furthermore, the study also indicated  that Chinese orchardgrass breeding has involved strong selection for adaptation  to forage production, which may result in restricted genetic base of orchardgrass  cultivar.
authors.affiliation: Department of Grassland Science, Animal Science and Technology College, Sichuan Agricultural University, Ya'an, P.R. China.
authors.forename: W G
authors.initials: WG
authors.lastname: Xie
authors.forename: X F
authors.initials: XF
authors.lastname: Lu
authors.forename: X Q
authors.initials: XQ
authors.lastname: Zhang
authors.forename: L K
authors.initials: LK
authors.lastname: Huang
authors.forename: L
authors.initials: L
authors.lastname: Cheng
mesh_terms: D000483:Alleles; D017931:DNA Primers / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics*; D031745:Dactylis / Q000145:classification* / Q000235:genetics*; D014644:Genetic Variation; D018745:Genome, Plant; D018895:Microsatellite Repeats; D010802:Phylogeny; D011110:Polymorphism, Genetic
chemical_list: D017931:DNA Primers; D018744:DNA, Plant