Transgenic friable, embryogenic oat callus cultures were selected for phosphinothricin (PPT) resistance following microprojectile bombardment with a plasmid encoding the Streptomyces hygroscopicus bar gene and the E. coli uidA gene.  From three microprojectile bombardment experiments, 111 PPT-resistant tissue cultures were shown to be transgenic based on Southern blot analysis.  From one to more than 20 copies of the transgenes were integrated in the genome of the PPT-resistant tissue cultures.  Coexpression of b-glucuronidase (GUS) activity due to expression of uidA was detected in 75% of the transgenic tissue cultures.  Plants were regenerated from 38 of the 111 transgenic tissue cultures.  Regenerated plants generally exhibited male sterility; however, more than 30 plants regenerated from one transgenic tissue culture were fully fertile.  GUS activity in the seed of fertile regenerated plants and PPT resistance in progeny of these plants cosegregated with bar and uidA sequences demonstrating stable inheritance of the transgenes.