Comparative RFLP mapping of meadow and tall fescue

Molecular markers based on restriction fragment length polymorphism (RFLP) were used to construct a genetic linkage map in diploid meadow fescue, Festuca pratensis Huds. (2n = 2x = 14, genomic designation PP), and to compare its genomic relationship with a related species, hexaploid tall fescue (Festuca nl arundinacea Schreb.; 2n=6x=42, PPG(1)G(1)G(2)G(2)). Using a collection of 66 tall-fescue (heterologous) markers, an RFLP linkage map was constructed in F. pratensis. This map, which has a total length of 280.1 cM, includes seven linkage groups. A comparison of 33 markers that were mapped in both F. pratensis and F. arundinacea detected highly conserved linkage groups between these two species. Our data are consistent with the proposal that one of the genomes of F. arundinacea was derived from F. pratensis. However, since significant changes in marker sequences, map distances, and homoeologous linkage groups were also detected between the two species, it appears that the P genome diverged substantially during evolution from the diploid to the hexaploid Festuca.