Methods for enhancing segregation of transgenes in plants and compositions thereof

A method for producing transgenic plant cells and plants comprising the steps of:

• a) introducing a DNA construct into a plant cell, wherein said DNA construct comprises a DNA molecule comprising a first T-DNA, a DNA molecule comprising a second T-DNA, and a plant expression cassette that expresses a conditional lethal gene product is located in a DNA segment between said first T-DNA and said second T-DNA, wherein said DNA segment containing said plant expression cassette has a length from about 1000 nucleotide base pairs to 15 nucleotide kilobase pairs;
• and
• b) treating said plant cell with a protoxin in amounts sufficient to cause the impairment of the cells when said protoxin is converted to a toxic compound by the expression product of the conditional lethal gene;
• and
• c) regenerating unimpaired plant cells into fertile plants.

A method for producing transgenic plant cells and plants comprising the steps of:

• a) introducing a DNA construct into a plant cell, wherein said DNA construct comprises a DNA molecule comprising a first T-DNA, a DNA molecule comprising a second T-DNA, and a plant expression cassette that expresses a conditional lethal gene product is located in a DNA segment between said first T-DNA and said second T-DNA, wherein said DNA segment containing said plant expression cassette has a length from about 1000 nucleotide base pairs to 15 nucleotide kilobase pairs;
• and
• b) growing said plant cell into a fertile plant;
• and
• c) collecting seeds from said fertile plant;
• and
• d) planting the seeds to cause germination of the seeds and growth of the seedlings;
• and
• e) treating the seedlings with a protoxin in amounts sufficient to cause the impairment of cells of the treated seedlings when said protoxin is converted to a toxic compound by the expression product of the conditional lethal gene.