Fertile transgenic barley of different cultivars obtained by adjustment of bombardment conditions to tissue response

Fertile transgenic barley (Hordeum vulgare L.) plants of five cultivars were obtained by an improved transformation protocol using different particle delivery devices. Varieties of barley which are hardly amenable for genetic transformation due to low tissue culture response were stably transformed by optimizing transformation parameters for each genotype separately according to their tissue culture response. Scutella of immature-zygotic embryos were transformed with the plasmid pAHC25 carrying the selectable marker gene bar and the reporter gene uidA. Gene delivery was optimized using the uidA-expression as transient marker for the transformation efficiency and taking into account the maintenance of the regeneration capacity after the bombardment. After selection on media with bialaphos as selective agent, 40 independently transformed plants were regenerated and analyzed for functional expression of the bar and uidA gene. Molecular analysis by Southern hybridization confirmed the integration of both genes into the nuclear genome of the plants. Thirty-five T-0-plants of five barley cultivars reached maturity so far. Analysis of the progeny confirmed the inheritance of the marker genes.