Methods and compositions for sweet corn sugary enhancer (SEI) gene

1. A method of identifying a corn plant or corn germplasm comprising an enhanced sugary gene locus, said method comprising:

a) detecting in an amplification reaction, in said plant or germplasm genomic DNA, a deletion located on maize chromosome 2 comprising SEQ ID NO: 4; and

b) identifying a corn plant or corn germplasm comprising the enhanced sugary gene locus.

2. A method of producing a corn plant that produces kernels with enhanced sugary trait, said method comprising:

a) detecting in an amplification reaction, in corn germplasm genomic DNA that is homozygous for the sugary (su1) mutant allele, the presence of a homozygous deletion located on maize chromosome 2 comprising SEQ ID NO: 4; and

b) producing a plant from said corn germplasm, thereby producing a corn plant with enhanced sugary trait.

3. The method of claim 1 , wherein the deletion comprises nucleotides from about position 10,028 to about position 10,642 of the nucleotide sequence of SEQ ID NO:6.

4. The method of claim 1 , wherein detecting the deletion comprises amplifying a region of the corn genome with a primer pair comprising a first oligonucleotide that hybridizes to the nucleotide sequence of SEQ ID NO:6 at a site 5′ to the location of the deletion at about position 10,028 and a second oligonucleotide that hybridizes to the nucleotide sequence of SEQ ID NO:6 at a site 3′ to the location of the deletion at about position 10,642 to produce an amplification product, wherein an amplification product that differs in base pair size from an amplification product of a control not comprising said deletion.

5. The method of claim 1 , wherein detecting said deletion comprises amplifying a region of the corn genome with a primer pair comprising a first oligonucleotide comprising the nucleotide sequence of SEQ ID NO:1 (forward primer) and a second oligonucleotide comprising the nucleotide sequence of SEQ ID NO:3 (reverse primer) to produce an amplification product, wherein an amplification product of about 170 base pairs detects the deletion.

6. A method of selecting a corn plant or corn germplasm comprising an enhanced sugary gene locus, said method comprising:

a) crossing a first corn plant or corn germplasm with a second corn plant or corn germplasm to produce progeny, wherein the first corn plant or corn germplasm comprises a deletion located on maize chromosome 2 comprising SEQ ID NO: 4,

b) detecting in an amplification reaction, in genomic DNA from one or more of said progeny, the presence of said deletion; and

c) selecting from said progeny of b) a corn plant or corn germplasm that comprises said deletion, thereby selecting a corn plant or corn germplasm comprising the enhanced sugary gene locus.

7. A method of introgressing an enhanced sugary gene locus into a corn plant having a genetic background lacking said gene locus, said method comprising:

a) crossing a donor comprising said gene locus with a recurrent parent that lacks said gene locus to produce progeny; and

b) repeatedly backcrossing progeny comprising said gene locus with the recurrent parent, wherein said progeny are identified by detecting the presence in an amplification reaction, in their genomic DNA, of a deletion comprising SEQ ID NO: 4 located on maize chromosome 2, thereby producing a corn plant comprising an enhanced sugary gene locus, and thereby introgressing said gene locus into a corn plant having a genetic background lacking said gene locus.

8. The method of claim 7 , wherein the genome of the corn plant comprising said enhanced sugary gene locus is at least 95% identical to that of a recurrent parent.

9. The method of claim 1 , wherein the deletion is a 615 base-pair deletion consisting of the nucleotide sequence of SEQ ID NO: 4.

10. The method of claim 1 , wherein the deletion can be identified in an amplification reaction with a primer pair comprising a first oligonucleotide comprising the nucleotide sequence of SEQ ID NO:1 (forward primer) and a second oligonucleotide comprising the nucleotide sequence of SEQ ID NO:3 (reverse primer) to produce an amplification product, wherein an amplification product of about 170 base pairs detects the deletion.

11. The method of claim 1 , wherein said detecting comprises detecting a homozygous deletion located on maize chromosome 2 comprising SEQ ID NO: 4.