Optimization of Barley Mature Embryo Regeneration and Comparison with Immature Embryos of Local Cultivars

Regeneration ability of plant cells or tissues in explant culture is one of the key factors affecting success of genetic transformation. In experiments, the effect of explant type (whole embryo, scutellum embryonic axis, meristematic/central zone of embryonic axis) and plant growth regulators (BAP or TDZ) on mature embryo regeneration was determined. Explant type significantly affected regeneration efficiency. While no regenerants were observed using mature scutella, whole embryos or embryonic axes produced the highest number of regenerants. Using embryonic axes with discarded apical and basal parts, regeneration efficiency dramatically decreased. No statistical differences in regeneration were observed between BAP and TDZ added to the regeneration medium in concentration 0.1 or 1 mg l-1. At last, regeneration ability of mature embryos of nine Slovak spring barley cultivars (Donaris, Ezer, Levan, Ludan, Nitran, Pribina Sladar, Orbit, Pax) and Golden Promise as a model cultivar was examined and compared with regeneration ability of immature embryos which have been usually used for genetic transformation of barley. Although the regeneration from mature embryos was very weak, the same cultivars Golden Promise, Pribina and Levan showed the best regeneration ability by using both, immature and mature embryos. On the other hand cultivars Ezer and Pax belonged to the weakest ones in both experiments.