Generation of haploid plants

1. A method of targeting a kinetochore protein for degradation, the method comprising:

a. introducing into a gamete cell of a parent plant a polypeptide comprising a peptide sequence linked to a protease cleavage site linked to N-degron linked to a kinetochore protein, wherein the peptide sequence is of sufficient length to block the polypeptide in an N-degron-dependent manner, and wherein the kinetochore protein is CENH3, and;

b. introducing into the gamete cell of a parent plant a protease that targets the protease cleavage site, thereby releasing the peptide sequence such that the N-degron is at the amino terminus of the polypeptide, thereby targeting the polypeptide for degradation.

2. The method of claim 1 , wherein one or two alleles of the endogenous kinetochore protein coding sequence of the plant is inactivated or knocked out.

3. The method of claim 1 , wherein the protease is a tobacco etch virus (TEV) protease.

4. The method of claim 1 , wherein the introducing in step a comprises expressing the polypeptide from an expression cassette comprising a promoter operably linked to a sequence encoding the polypeptide.

5. The method of claim 4 , wherein the promoter is a kinetochore protein gene promoter.

6. The method of claim 1 , wherein the introducing in step b comprises expressing the polypeptide from an expression cassette comprising a heterologous promoter specific for a gamete lineage operably linked to a sequence encoding the protease.

7. The method of claim 6 , wherein the promoter specific for a gamete lineage is specific for a central cell, egg cell, or sperm cell.

8. The method of claim 1 , further comprising generating selfed progeny from the plant and selecting progeny from the plant having half the chromosomes of the plant.

9. The method of claim 8 , wherein the selected progeny are haploid.

10. The method of claim 9 , further comprising generating doubled haploid plants from the haploid progeny.

11. A plant comprising:

a first expression cassette comprising a promoter operably linked to a polynucleotide encoding a polypeptide comprising a peptide sequence linked to a protease cleavage site linked to N-degron linked to a kinetochore protein, wherein the peptide sequence is of sufficient length to block the polypeptide in an N-degron-dependent manner and wherein the kinetochore protein is CENH3, and

a second expression cassette comprising a heterologous promoter linked to a second polynucleotide encoding the protease, wherein the heterologous promoter is specific for a gamete lineage.

12. The plant of claim 11 , wherein the promoter specific for a gamete lineage is specific for a central cell, egg cell, or sperm cell.

13. An expression cassette comprising a promoter operably linked to a polynucleotide encoding a polypeptide comprising a peptide sequence linked to a protease cleavage site linked to N-degron linked to a kinetochore protein, wherein the kinetochore protein is CENH3.