Long-term cryopreservation of Greek fir embryogenic cell lines: recovery, maturation and genetic fidelity

In coniferous species, including Greek fir (Abies cephalonica Loud), the involvement of somatic embryo plants in breeding and reforestation programs is dependent on the success of long-term cryostorage of embryogenic cultures during clonal field testing. In the present study on Greek fir, we assayed the recovery, morphological characteristics and genetic fidelity of embryogenic cell lines 6 and 8 during proliferation and maturation after long-term cryostorage. Our results indicate successful recovery of both cell lines after 6 years in cryostorage. In the maturation phase, both cell lines were capable of producing somatic embryos although some differences were detected among experiments. However, these changes were more dependent on the differences in the components of the maturation media or in the experimental set-up than on the long-term cryostorage. During both proliferation and maturation phases, the morphological fidelity of the embryogenic cultures as well as of the somatic embryos were alike before and after cryopreservation. The genetic fidelity of the cryopreserved cell line 6 that was assayed by random amplified polymorphic DNA (i.e. RAPD) markers demonstrated some changes in the RAPD profiles. The results indicate possible genetic aberrations caused by long-term cryopreservation or somaclonal variation during the proliferation stage. However, in spite of these changes the embryogenic cultures did not lose their proliferation or maturation abilities.