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United States Department of Agriculture

Agricultural Research Service

Title: Microsatellite Markers and Genetic Diversity Assessment in Lolium Temulentum

Authors
item Kirigwi, Francis - S.R. NOBLE FOUNDATION
item Zwonitzer, John - PLANT PATH, NC STATE UNIV
item Mian, Rouf
item Wang, Zeng-Yu - S.R. NOBLE FOUNDATION
item Saha, Malay - S.R. NOBLE FOUNDATION

Submitted to: Genetic Resources and Crop Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 29, 2007
Publication Date: April 18, 2007
Repository URL: http://hdl.handle.net/10113/32256
Citation: Kirigwi, F.M., Zwonitzer, J.C., Mian, R.M., Wang, Z., Saha, M.C. 2007. Microsatellite Markers and Genetic Diversity Assessment in Lolium Temulentum. Genetic Resources and Crop Evolution. 55(1):105-114.

Interpretive Summary: Darnel ryegrass (Lolium temulentum) is widely distributed throughout the world. It grows as weed in wheat and barley fields. It is a long day annual grass that is classified as a noxious weed in Arkansas and as a plant pest in South Carolina. However, because of the simplicity of the biology of darnel ryegrass, it is being used as a model species for genetic and genomic studies in forage and turf grasses. A study with 41 darnel ryegrass, three tall fescue (Festuca arundinacea), two tetraploid fescue (F. glaucescens), and two meadow fescue (F. pratensis) genotypes was initiated to: (i) identify a set of microsatellite (simple sequence repeats) markers useful for L. temulentum, and (ii) utilize such markers for assessing the genetic variability of L. temulentum accessions collected from different geographical regions of the world. A total 30 tall fescue EST-SSRs and 32 F×L genomic SSRs were used for analysis of all genotypes. We have developed a set of microsatellite markers for Lolium temulentum. These markers were effective for genetic diversity analysis of Festuca and Lolium species. The L. temulentum accessions grouped into five major clusters while tall fescue, meadow fescue and tetraploid fescue each formed their separate clusters. L. temulentum accession ABY-BA 8892.78 was closer to meadow fescues than to other L. temulentum genotypes in the study. This accession appeared as a unique individual and merits further study. This line can be crossed with distantly related L. temulentum lines to develop genetically diverse hybrid plants. Such hybrids can be useful for various research purposes, including generation of highly tissue culture responsive genotypes. The diversity information from this study will be useful in future Festuca and Lolium and Festuca × Lolium improvement.

Technical Abstract: Lolium and Festuca are two important genera of cool-season forage and turf grasses worldwide. Cultivated Lolium species have high quality and digestibility, and establish easily while major Festuca species generally have better persistence and stress tolerance. Lolium temulentum (darnel ryegrass) has been proposed as a model species for genomics studies of cool-season forage and turf grasses. A study with 41 darnel ryegrass, three tall fescue (Festuca arundinacea), two tetraploid fescue (F. glaucescens), and two meadow fescue (F. pratensis) genotypes was initiated to: (i) identify a set of microsatellite (simple sequence repeats) markers useful for L. temulentum, and (ii) utilize such markers for assessing the genetic variability of L. temulentum accessions collected from different geographical regions of the world. A total of 40 tall fescue (TF) EST-SSRs and 60 Festuca-Lolium (F×L) genomic SSRs were screened on a subset of eight genotypes. The selected 30 tall fescue EST-SSRs and 32 F×L genomic SSRs were used for analysis of all genotypes. The TF-EST - and the F×L genomic- SSRs resulted in 10.3 and 9.3 alleles per marker, respectively with an average polymorphic information content (PIC) value of 0.66. The L. temulentum accessions grouped into five major clusters while tall fescue, meadow fescue and tetraploid fescue formed their separate clusters. Tall fescue PI423078 was found to be quite different from KY31 and PI297901. L. temulentum accession ABY-BA 8892.78 was closer to meadow fescues than to other L. temulentum genotypes in the study. The results also indicate that the tetraploid fescues are the most distant from L. temulentum. We report a set of tall fescue EST- and F×L genomic SSRs for L. temulentum and demonstrate the utility of the markers in assessing the genetic diversity among L. temulentum accessions. The genetic diversity information generated in this study will be valuable in using the L. temulentum accessions for genetic improvement of darnel ryegrass and other members of the Festuca-Lolium complex.

Last Modified: 7/22/2014
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