Development of a shoot regeneration protocol for genetic transformation in Pelargonium zonale and Pelargonium peltatum hybrids

The attempts of this investigation were to develop a system for plant regeneration from explants of adult plants and its use for genetic transformation of important commercial Pelargonium zonale hybrid and P. peltatum hybrid cultivars. To this aim, leaf blade and petiole explants of eight cultivars were cultured on modified MS (Murashige and Skoog, 1962) medium with two concentrations of TDZ, BA, and zeatin (5 and 20 micromolar). Petiole explants showed a higher regeneration response than leaf blade explants and TDZ was the most effective cytokinin. Petioles of 16 cultivars were incubated on medium containing 5, 10, 15, and 20 micromolar TDZ, respectively, in order to identify the most effective TDZ concentration. For the majority of genotypes 10 micromolar TDZ resulted in the best regeneration response. Cefotaxim at 500 mg l(-1) had no effect on shoot regeneration and did not show interaction with glufosinate. For selection of transgenic cells, a concentration of 2.5 micromolar glufosinate was shown to be appropriate. LBA4404 and EHA101 Agrobacterium strains carrying pIBGUS vector with pat gene as selectable marker gene and GUS gene as reporter gene were compared in transformation studies. With regard to GUS expression in petiole explants 16 days after coculture, better results were obtained with EHA 101 than with LBA 4404.