Improved Agrobacterium-mediated co-transformation and selectable marker elimination in transgenic rice by using a high copy number pBin19-derived binary vector

► Antibiotic marker elimination in transgenics avoids horizontal transfer to bacteria. ► Agrobacterium co-transformation followed by segregation enabled marker elimination. ► Placing a transgene on a 12-copy binary vector increased co-transformation to 86%. ► Marker was eliminated in four co-transformed rice plants with the osmotin transgene. ► Marker elimination by co-transformation avoids residual recombination sites.