Progeny Analysis of Glyphosate Selected Transgenic Soybeans Derived from <i>Agrobacterium</i>‐Mediated Transformation

Abstract

Glyphosate selection has been implemented into an Agrobacterium ‐mediated transformation system for soybean [ Glycine max (L.) Merr.]. Cotyledonary explants were excised from 5‐d‐old seedlings and inoculated with an Agrobacterium strain carrying the CP4 gene, which confers tolerance to the herbicide Roundup, and the β‐glucuronidase (GUS) gene. Explants were selected on sublethal levels of glyphosate during shoot initiation and elongation. Glyphosate tolerant shoots were identifiable after 8 to 12 wk of selection. Coexpression of GUS occurred in approximately 80% of the primary transformants (R 0 ). The R 0 plants were fully fertile, with no apparent phenotypic abnormalities. Progeny analysis from 81 independent transgenic soybean events derived from glyphosate selection demonstrated that the majority of the transformants transmitted the transgenes as a single functional locus.