Methods and Vectors for Producing Transgenic Plants

A recombinant nucleic acid molecule comprising:

• a first DNA segment comprising a first transcription unit flanked on both sides and adjacent to a first and a second shorter transcribable nucleic acid sequence in opposite orientation to each other and located between a first left T-DNA border region and a first right T-DNA border region;
• a second DNA segment comprising a second transcription unit flanked on both sides and adjacent to a third and a fourth shorter transcribable nucleic acid sequence in opposite orientation to each other and located between a second left T-DNA border region and a second right T-DNA border region, wherein said third shorter transcribable nucleic acid sequence is operably linked to a plant-expressible promoter, wherein a fifth shorter transcribable nucleic acid sequence is located on the opposite side of, and adjacent to, said second right T-DNA border region and in opposite orientation to said fourth shorter transcribable nucleic acid sequence;
• and
• wherein said first, second, third, fourth, and fifth shorter transcribable nucleic acid sequences are homologous to a portion of said second transcription unit;
• and
• a third transcription unit comprising a non-lethal negative selectable marker gene located between said first DNA segment and said second DNA segment;
• wherein said T-DNA border regions are capable of enabling the transfer of said segments into a plant genome.