Sweet corn

L. Curtis Hannah hannah at GNV.IFAS.UFL.EDU
Sun Nov 21 13:45:15 EST 1999


Dear Mr Commens,

    In response to your questions:


The terms se, sh2 and su (for sugary enhancer, shrunken2 and sugary) refer
to genes in the maize genome.  Maize genes are usually named for the
phenotype conditioned by recessive alleles.  The shrunken2 and sugary genes
are classics in the maize literture and were described very early, I
believe in the 40's or 50's.  In these cases, the loss of the wildtype or
functional allele gave rise to a kernel that was viewed as shrunken (some
of the early workers referred to exactly the same phenotype as brittle) or
sugary, in the case of the Sugary1 gene.

    The sugary-enhancer gene was named by Dr. R. A. Brink much later, I
believe in the 70s or 80s.  The name refers to the increased sugar content
conditioned by this gene in lines homozygous for the recessive su1 gene.

	Finally, plant breeding cannot achieve these classes although for these
genes to be used commercially, there has been a lot of intensive plant
breeding done.

	I should probably also mention that these mutant genes were found in
Nature and are not the products of genetic engineering.  However, better
versions of these mutant genes are being synthesized via genetic
engineering and will be, in my view,  just as safe for sweet corn as the
classic mutants.


At 07:32 PM 11/21/1999 +1000, David A Commens wrote:
>Could you please tell me exactly what the various terms se, sh2 and su mean
>and how they came about? I know that they stand for sugary enhancer,
>shrunken 2 and sugary, but I would like to know what makes them fit into
>their catagories. Also what plant breeding is performed to achieve such
>classes.
>
>Kind Regards,
>David Commens.
>dcommens at icr.com.au
>
L. Curtis Hannah

   Professor and Director, Graduate Program in Plant Molecular and Cellular
   Biology
   Horticultural Sciences
   http://www.hos.ufl.edu/lchweb/
   352-392-4726, PMCB Office
   352-392-1928 ext 315, office
   352-392-1928 ext 314, Hannah lab
   352-392-1928 ext 202, secretary
   352-392-5653, fax




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