Phenotypic characterization of the progenies of rice plants derived from cryopreserved calli

The progenies of rice plants (Oryza sativa L.) differentiated from calli th at had been cryopreserved and from control (non-cryopreserved) calli were u sed to study the influence of selection pressure during cryopreservation. T he phenotypic evaluation of these progenies was based mainly on the respons e of seedlings and calli to freezing stress and on the characterization of protoplast and cell populations by flow cytometric analyses. The patterns o f response to freezing stress, as well as the variations in some morphologi cal and physiological cell parameters, were unrelated to the origin (cryopr eserved or control calli) of the parental plants.