Progeny analysis of glyphosate selected transgenic soybeans derived from Agrobacterium-mediated transformation

Glyphosate selection has been implemented into an Agrobacterium-mediated tr ansformation system for soybean [Glycine max (Lh) Merr.]. Cotyledonary expl ants were excised from 5-d-old seedlings and inoculated with an Agrobacteri um strain carrying the CP4 gene, which confers tolerance to the herbicide R oundup, and the beta-glucuronidase (GUS) gene;Explants were selected on sub lethal levels of glyphosate during shoot initiation and elongation. Glyphos ate tolerant shoots were identifiable after 8 to 12 wk of selection. Coexpr ession of GUS occurred in approximately 80% of the primary transformants (R -0). The R-0 plants were fully fertile, with no apparent phenotypic abnorma lities. Progeny analysis from 81 independent transgenic soybean events deri ved from glyphosate selection demonstrated that the majority of the transfo rmants transmitted the transgenes as a single functional locus.