Development of a genomic microsatellite library in perennial ryegrass (Lolium perenne) and its use in trait mapping

Background and Aims: Perennial ryegrass (Lolium perenne) is one of the key forageand amenity grasses throughout the world. In the UK it accountsfor 70 % of all agricultural land use with an estimated farmgate value of £6 billion per annum. However, in termsof the genetic resources available, L. perenne has lagged behindother major crops in Poaceae. The aim of this project was thereforethe construction of a microsatellite-enriched genomic libraryfor L. perenne to increase the number of genetic markers availablefor both marker-assisted selection in breeding programmes andgene isolation. Methods: Primers for 229 non-redundant microsatellite markers were designedand used to screen two L. perenne genotypes, one amenity andone forage. Of the 229 microsatellites, 95 were found to showpolymorphism between amenity and forage genotypes. A selectionof microsatellite primers was selected from these 95 and usedto screen two mapping populations derived from intercrossingand backcrossing the two forage and amenity grass genotypes. Key Results and Conclusions: The utility of the resulting genetic maps for analysis of thegenetic control of target traits was demonstrated by the mappingof genes associated with heading date to linkage groups 4 and7.