Isolation, Culture, and Plant Regeneration of Suspension-Derived Protoplasts of Lolium

An efficient protoplast regeneration system makes somatic hybridization and direct gene transfer attractive tools in the breeding of perennial ryegrass, one of the most important forage grass species in temperate regions. Despite many efforts during the last decade, regeneration from protoplasts of Lolium perenne L. has generally been low and further complicated by the frequent occurrence of albino plantlets (1 –3 ). Recently, however, the use of nurse culture (4 ,5 ) and conditioned medium (5 ,6 ) has considerably improved plating efficiencies and reproducibility.