Genetic analysis of forage grasses based on heterologous RFLP markers detected by rice cDNAs

Genetic polymorphism within and between three species of forage grasses; perennial ryegrass (Lolium perenne L.), meadow fescue (Festuca pratensis Huds.) and tall fescue (Festuca arundinacea Schreb.) was analyzed using RFLP markers detected by rice cDNA probes developed in the Rice Genome Research Program of Japan (RGP). One hundred and ninety seven rice cDNA clones were used for hybridization to genomic DNA of forage grasses. Many of the rice cDNA clones produced no visible band or a smear with no discrete bands. Twenty three clones showed high efficiency cross-hybridization to the genomic DNA of forage grasses. Genetic variation was evaluated for five varieties and one population of forage grasses using twelve polymorphic rice cDNA RFLP probes. Genetic variability within varieties as measured by Rogers’ genetic distance was considerably lower for the F. pratensis variety ‘Tomosakae’ than for the L. perenne and F. arundinacea varieties. To determine genetic diversity between varieties of different species, cluster analysis was performed using data from the twelve RFLP probes. The two accessions of Lolium perenne were clustered more closely together than the2three varieties of F. arundinacea. Two Japanese varieties of F. arundinacea were grouped in the same cluster. The variety-specific RFLP markers were observed among six accessions of L. perenne, F. pratensis and F. arundinacea. Such variety-specific RFLP markers would provide very useful tools for breeding programs such as intergeneric hybridization of Lolium and Festuca genera.