Transgenic cereal (tritordeum) plants obtained at high efficiency by microprojectile bombardment of inflorescence...

Transgenic cereal plants expressing the beta-glucuronidase (uidA) and neomycin phosphotransferase (neo) genes were obtained via microprojectile bombardment of immature inflorescence tissue of tritordeum (the fertile Hordeum x Triticum amphiploid, HchHchAABB). A total of 17 independent transgenic plants were recovered from 32 bombardments (on average four inflorescences per shot). Of the bombardment and culture parameters tested, explant preculture had the most influence on stable transformation frequency. The uidA and neo genes were supplied on two separate plasmids (co-transformation) and 88% of the transgenic plants recovered expressed both genes. Southern analysis confirmed the results of histochemical GUS and NPT II assays. Transgenic plants were grown to maturity and flowered and set seed. Pollen from four T0 GUS+ plants analysed showed GUS activity and T1 seedlings derived from one of the transgenic plants showed a segregation of 2.75:1 (GUS+:GUS-) for uidA gene activity.