Optimisation of transient transformation of a South African spring wheat cultivar with particle bombardment

Transient transformation was optimised for bread wheat, Triticum aestivum L. cv Kariega, using a particle inflow gun constructed at ARC-Roodeplaat. Excised immature embryos, cultured in vitro for 5 to 7 days, were bombarded with pAHC25 and analysed for the presence of the β-glucuronidase reporter gene. Three bombardment variables were optimised and most blue spots were obtained with a helium pressure of 600 kPa, 20 mm particle flight distance and 0.4 Mosmoticum in the bombardment medium. Furthermore, the maize ubiquitin promoter was shown to be functional in Kariega.