Field performance of cell suspension-derived tall fescue regenerants and their half-sib families

The application of biotechnology to forage grass has the potential to compl ement and speed up conventional breeding. To ascertain the suitability of r egenerants for improvement programs, primary regenerants of tall fescue (Fe stuca arundinacea Schreb,) cv Tacuabe and their progenies were investigated in a field experiment located in Eschikon near Zurich (Switzerland). There by, the following two aspects were focused on. First, do regenerated plants and their progenies perform similar to seed-grown plants; and second, do d ifferent regeneration systems have an effect on the performance of the rege nerants? Two sets of plants, regenerated from different single-genotype der ived embryogenic suspension cultures (ESC) of tall fescue, were evaluated f or agronomic traits in a replicated field experiment for three growing seas ons. Embryogenic suspension cultures were either routinely subcultured or c ryopreserved and re-established. Seed from the primary regenerated and seed -grown plants were harvested to evaluate morphological and phenological tra its of corresponding half-sib progenies in a further field experiment. When compared with seed-grown plants of the same cultivar, primary regenerants showed reduced vegetative growth and fertility. The performance of plants r egenerated from cryopreserved-reestablished ESC was not inferior to corresp onding plants regenerated from routinely subcultured ESC, The performance o f progenies of regenerated plants did not differ from those of seed-grown p lants and was within the range of the cultivar, There was no effect of the regeneration system on the performance of corresponding progenies; thus, su ggesting that the weak growth of the primary regenerants was most likely of epigenetic origin. Therefore regenerated plants can be integrated into bre eding programs without major restrictions.