Fig. 1 Crossing scheme for introgression of Festuca mairei genomes (MMM'M') into Lolium perenne (LL). The 4x F₁ hybrid, F. mairei (4x) x L. perenne (2x), was used as the female in backcrossing to L. perenne. Fourteen BC₁ plants were interpollinated to produce BC₁G₁ progeny containing from chromosomes