From Wikipedia. I don't see any information about human induced mutagen to cause mutation resulting in sweet corn.
While Wikipedia not always 100% correct, I find that they are fairly reliable.
History
Sweet corn occurs as a spontaneous mutation in
field corn and was grown by several
Native American tribes. The
Iroquois gave the first recorded sweet corn (called 'Papoon') to European settlers in 1779.<sup id="cite_ref-RJSch_2-0" class="reference">
[2]</sup> It soon became a popular food in southern and central regions of the United States.
Young sweet corn
Open pollinated cultivars of white sweet corn started to become widely available in the United States in the 19th century. Two of the most enduring cultivars, still available today, are 'Country Gentleman' (a
Shoepeg corn with small kernels in irregular rows) and 'Stowell's Evergreen'.
Sweet corn production in the 20th century was influenced by the following key developments:
- hybridization allowed for more uniform maturity, improved quality and disease resistance
- In 1933 'Golden Cross Bantam' was released. It is significant for being the first successful single-cross hybrid and the first specifically developed for disease resistance (Stewart's wilt in this case).<sup id="cite_ref-3" class="reference">[3]</sup>
- identification of the separate gene mutations responsible for sweetness in corn and the ability to breed cultivars based on these characteristics:
- su (normal sugary)
- se (sugary enhanced, originally called Everlasting Heritage)
- sh2 (shrunken-2)<sup id="cite_ref-DLLarson_4-0" class="reference">[4]</sup>
There are currently hundreds of cultivars, with more constantly being developed.
Anatomy
The same rows of corn 41 days later at maturity.
The
fruit of the sweet corn plant is the corn
kernel, a type of fruit called a
caryopsis. The
ear is a collection of kernels on the
cob. Because corn is a
monocot, there is always an even number of rows of kernels.<sup class="noprint Inline-Template" style="white-space:nowrap;">[
further explanation needed]</sup> The ear is covered by tightly wrapped leaves called the
husk.
Silk is the name for the
pistillate flowers, which emerge from the husk. The husk and silk are removed by hand, before boiling but not necessarily before roasting, in a process called
husking or
shucking.
Consumption
In most of
Latin America, sweet corn is traditionally eaten with beans; each plant is deficient in an
essential amino acid that happens to be abundant in the other, so together sweet corn and beans form a protein-complete meal.<sup id="cite_ref-5" class="reference">
[5]</sup> In
Brazil, sweet corn cut off from the cobs is generally eaten with
peas (where this combination, given the practicality of steamed canned grains in an urban diet, is a frequent addition to diverse meals such as salads, stews, seasoned white rice, risottos, soups, pasta, and, most famously, whole sausage hot dogs).
Similarly, sweet corn in
Indonesia is traditionally ground or soaked with
milk, which makes available the
B vitamin niacin in the corn, the absence of which would otherwise lead to
pellagra; in Brazil, a combination of ground sweet corn and milk is also the basis of various well-known dishes, such as
pamonha and the pudding-like dessert
curau, while sweet corn eaten directly off the cobs tends to be served with butter.
The kernels are boiled or steamed. In Europe, China, Korea, Japan and India, they are often used as a
pizza topping, or in
salads.
Corn on the cob is a sweet corn cob that has been boiled, steamed, or grilled whole; the kernels are then eaten directly off the cob or cut off.
Creamed corn is sweet corn served in a milk or cream sauce. Sweet corn can also be eaten as
baby corn.
In the United States, sweet corn is eaten as a steamed vegetable, or on the cob, usually served with butter and salt. It can be found in Tex-Mex cooking in chili, tacos, and salads. When corn is mixed with
Lima beans it is called
Succotash.
If left to dry on the plant, kernels may be taken off the cob and cooked in oil where, unlike
popcorn, they expand to about double the original kernel size and are often called
corn nuts. A soup may also be made from the plant, called sweet corn soup.
Health benefits
Overripe sweet corn
Cooked sweet corn increases levels of
ferulic acid, which has anti-
cancer properties. <sup id="cite_ref-6" class="reference">
[6]</sup>
Cultivars
Main article:
List of sweetcorn varieties
Open pollinated (non-
hybrid) corn has largely been replaced in the commercial market by sweeter, earlier hybrids, which also have the advantage of maintaining their sweet flavor longer.
Su cultivars are best when cooked within 30 minutes of harvest. Despite their short storage life, many open pollinated cultivars such as 'Golden Bantam' remain popular for home gardeners and specialty markets, or are marketed as
heirloom seeds. Although less sweet, they are often described as more tender and flavorful than hybrids.
Genetics
Early cultivars, including those used by Native Americans, were the result of the mutant
su ("sugary")
allele.<sup id="cite_ref-RJSch_2-1" class="reference">
[2]</sup> They contain about 5–10% sugar by weight.
Supersweet corn are cultivars of sweet corn which produce higher than normal levels of sugar developed by
University of Illinois at Urbana–Champaign professor John Laughnan.<sup id="cite_ref-DLLarson_4-1" class="reference">
[4]</sup> He was investigating two specific
genes in sweet corn, one of which, the
sh2 gene, caused the corn to shrivel when dry. After further investigation Laughnan discovered that the endosperm of
sh2 sweet corn kernels store less starch and from 4 to 10 times more sugar than normal
su sweet corn. He published his findings in 1953, disclosing the advantages of growing supersweet sweet corn, but many corn breeders lacked enthusiasm for the new supersweet corn. Illinois Foundation Seeds Inc. was the first seed company to release a supersweet corn and it was called 'Illini Xtra Sweet', but widespread use of supersweet hybrids did not occur until the early 1980s. The popularity of supersweet corn rose due to its long shelf life and large sugar content when compared to conventional sweet corn. This has allowed the long-distance shipping of sweet corn and has enabled manufacturers to can sweet corn without adding extra sugar or salt.
Cut White Sweet Corn
The third gene mutation to be discovered is the
se or "sugary enhanced" allele, responsible for so-called "Everlasting Heritage" cultivars, such as 'Kandy Korn'. Cultivars with the
se alleles have a longer storage life and contain 12–20% sugar compared to
su cultivars.
All of the alleles responsible for sweet corn are
recessive, so it must be isolated from other corn, such as field corn and
popcorn, that release pollen at the same time; the
endosperm develops from genes from both parents, and
heterozygous kernels will be tough and starchy. The
se and
su alleles do not need to be isolated from each other. However supersweet cultivars containing the
sh2 allele must be grown in isolation from other cultivars to avoid cross-
pollination and resulting starchiness, either in space (various sources quote minimum quarantine distances from 100 to 400 feet or 30 to 120 m) or in time (i.e., the supersweet corn does not pollinate at the same time as other corn in nearby fields).
Modern breeding methods have also introduced cultivars incorporating multiple gene types:
- sy (for synergistic) adds the sh2 gene to some kernels (usually 25%) on the same cob as a se base (either homozygous or heterozygous)
- augmented sh2 adds the se and su gene to a sh2 parent
Often seed producers of the
sy and
augmented sh2 types will use brand names or trademarks to distinguish these cultivars instead of mentioning the genetics behind them. Generally these brands or trademarks will offer a choice of white, bi-color and yellow cultivars which otherwise have very similar characteristics.
unctuationKerning/> <w:ValidateAgainstSchemas/> <w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid> <w:IgnoreMixedContent>false</w:IgnoreMixedContent> <w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText> <w
oNotPromoteQF/> <w:LidThemeOther>EN-US</w:LidThemeOther> <w:LidThemeAsian>X-NONE</w:LidThemeAsian> <w:LidThemeComplexScript>X-NONE</w:LidThemeComplexScript> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> <w
