Patent ID: 7432082

Claim:
A method for detecting a mutant allele of a wheat acetohydroxyacid synthase large subunit (AHASL) gene that confers tolerance to imidazolinone herbicides on a wheat plant, said method comprising the steps of: (a) obtaining genomic DNA from a wheat plant; (b) using said DNA as a template for a PCR amplification comprising said DNA, polymerase, deoxyribonucleotide triphosphates, a forward AHASL-gene-specific primer, a reverse AHASL-gene-specific primer, and a mutant-allele-specific primer comprising a nucleotide sequence with a 5′ end and a 3′ end, wherein said nucleotide sequence is capable of annealing to the complement of nucleotides 3 to 23 of SEQ ID NO: 12, and wherein the 3′-end nucleotide of said nucleotide sequence is cytidine and said cytidine hybridizes to the site of the G-to-A point mutation that gives rise to the S653(At)N substitution in an AHASL protein, and wherein said mutant-allele-specific primer comprises the nucleotide sequence set forth in SEQ ID NO: 3; and (c) detecting a product of said PCR amplification, said product corresponding to the region of said AHASL gene bounded by the annealing sites of the mutant-allele-specific primer and the reverse AHASL-gene-specific primer on said AHASL gene, wherein detecting said product indicates the presence of a mutant allele of a wheat AHASL gene; wherein said mutant-allele-specific primer is capable of annealing to a region of an AHASL gene that is nested between the annealing sites of said forward and reverse AHASL-gene-specific primers.