Flowering in Lolium perenne (perennial ryegrass) results in reduced digestibility and its inhibition would enhance forage quality. Flowering regulation has been well studied in Arabidopsis thaliana (Simpson and Dean, 2002) and orthologs of Arabidopsis flowering genes underlying heading date Quantitative Trait Loci (QTL) have been identified in rice (Yano, M et al., 2000). However it is not clear yet how universally applicable such studies are to Lolium. The project goals are to characterise the gene expression profiles of late/rare flowering L. perenne plants to determine factors affecting flowering and to map the genes involved in the flowering process. Initial studies, reported here, have focussed on the ability of 6 plant lines from the Oak Park breeding programme, previously identified as rare or non-flowering under natural day length conditions, to flower in controlled environments