Dent corn tasted good…didn’t it?
There was a time when you could go out into a field
of regular dent (field) corn, right around the time the kernels were
at milk stage, and pick several ears to make, what was thought to be
at the time, a pretty tasty meal. Those were the good old days,
I don’t think so….
Finding a naturally occurring mutation of dent corn
that happened to produce kernels consisting mostly of sugar rather
than starch changed the expectations of all who like to eat corn
with their meal. The plant that resulted from this mutation was
called sweet corn. The problem for growers is that generally
speaking, the higher the eating quality of the corn; the harder it
is to grow in the field.
Alphabet Soup of Sweet Corn
There are 3 basic types of sweet corn that are
classified by the gene that gives the plant its characteristics.
– commonly referred to as Normal types, contain the “sugary” su
gene. The su type contain anywhere from a 9% to 16% sugar
content. These types tend to lose their sweetness rapidly after
maturity, but have a good “corn flavor” and are the easiest to
grow in the field.
referred to as “Sugary Enhanced” contain the se gene. These
types are generally sweeter than the su types with 14% to 35%
sugar content, and are known for a tender kernel, creamy
texture, and good “corn flavor”.
referred to as “SuperSweet” or “Shrunken 2” contains the sh2
gene. These types are the sweetest of the three types mentioned
here with a sugar content of 28% to 44%. The sh2
gene not only gives the corn a higher sugar level, but that
sugar level is maintained longer than either su or se types.
This type is the most difficult to plant and grow, due to the
lighter seed, relatively poor vigor, greater susceptibility to
diseases, and the characteristic shrunken and shriveled seed.
SuperSweet types can also have a slightly tougher kernel, less
of a creamy texture, and less “corn flavor”.
There are also genes called “modifier genes” that can
be added to each sweet corn type to improve eating quality. The
addition of these “modifier genes” and whether one or both of the
parents have the best eating quality traits are two ways to develop
distinct varieties within each sweet corn type.
Solutions for sweet corn growers
Sweet corn breeders
are currently combining the 3 basic types mentioned above in an
attempt to get the best characteristics of each type into one
variety. One of the biggest challenges is to combine high quality
eating characteristics with high vigor seed that is easy to grow in
the field. Breeders are getting closer, but still have some work in
are also working to help solve the plantability and stand
establishment problems of some of the high quality sweet corn
varieties. One thought, is to apply an “artificial seed coat” to
the seed. An “Artificial Seed Coat” could be helpful in 3 ways;
it can add weight to the seed and smooth out the
cracks and crevasses in a shrunken, wrinkled seed improving
the coat can be formulated to optimize the rate
at which moisture is absorbed by the seed, minimizing seed
damage due to cool wet soil conditions, and
the coat can be used as a platform to add larger
quantities of materials that may be helpful in establishing
stands in the field. An example of this would be the addition
of bacteria that produce a “Systemic Acquired Resistance” (SAR)
in the plant. This type of bacteria can initiate a plant immune
response to help defend against diseases that are common
problems when establishing high quality sweet corn varieties in
Below is a cross section of an SH2 sweet
corn seed with an experimental artificial coat. Note the irregular,
almost star shape of the seed and how the coat fills and bridges the
cracks and crevasses.