Original Paper

Theoretical and Applied Genetics

, Volume 109, Issue 2, pp 294-304

First online:

Genetic linkage mapping of an annual × perennial ryegrass population

  • S. E. WarnkeAffiliated withNational Arboretum, USDA-ARS Email author 
  • , R. E. BarkerAffiliated withNational Forage Seed Production Research Center, USDA-ARS
  • , Geunhwa JungAffiliated withDepartment of Plant Pathology, University of Wisconsin
  • , Sung-Chur SimAffiliated withDepartment of Plant Pathology, University of Wisconsin
  • , M. A. Rouf MianAffiliated withThe Noble Foundation
  • , M. C. SahaAffiliated withThe Noble Foundation
  • , L. A. BrilmanAffiliated withSeed Research of Oregon
  • , M. P. DupalAffiliated withAmersham Biosciences Pty. Ltd.
  • , J. W. ForsterAffiliated withDepartment of Primary Industries, Primary Industries Research Victoria, Plant Biotechnology Centre, La Trobe University

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access


Annual (Lolium multiflorum Lam.) and perennial (L. perenne L.) ryegrass are two common forage and turfgrass species grown throughout the world. Perennial ryegrass is most commonly used for turfgrass purposes, and contamination by annual ryegrass, through physical seed mixing or gene flow, can result in a significant reduction in turfgrass quality. Seed certifying agencies in the United States currently use a test called seedling root fluorescence (SRF) to detect contamination between these species. The SRF test, however, can be inaccurate and therefore, the development of additional markers for species separation is needed. Male and female molecular-marker linkage maps of an interspecific annual × perennial ryegrass mapping population were developed to determine the map location of the SRF character and to identify additional genomic regions useful for species separation. A total of 235 AFLP markers, 81 RAPD markers, 16 comparative grass RFLPs, 106 SSR markers, 2 isozyme loci and 2 morphological characteristics, 8-h flowering, and SRF were used to construct the maps. RFLP markers from oat and barley and SSR markers from tall fescue and other grasses allowed the linkage groups to be numbered, relative to the Triticeae and the International Lolium Genome Initative reference population P150/112. The three-generation population structure allowed both male and female maps to be constructed. The male and female maps each have seven linkage groups, but differ in map length with the male map being 537 cm long and the female map 712 cm long. Regions of skewed segregation were identified in both maps with linkage groups 1, 3, and 6 of the male map showing the highest percentage of skewed markers. The (SRF) character mapped to linkage group 1 in both the male and female maps, and the 8-h flowering character was also localized to this linkage group on the female map. In addition, the Sod-1 isozyme marker, which can separate annual and perennial ryegrasses, mapped to linkage group 7. These results indicate that Lolium linkage groups 1 and 7 may provide additional markers and candidate genes for use in ryegrass species separation.