Envoy at 15:32, 13 September 2007

2007-09-13T15:32:58Z

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[[Image:vegCorn.jpg|thumb|Husked sweetcorn]]
'''Sweet corn''' (''Zea mays'' var. ''rugosa''<ref>{{cite web | title = Sweet Corn | publisher = [[Oregon State University]] | work = Horticulture 233 webpage | url = http://oregonstate.edu/dept/hort/233/sweetcorn.htm }}</ref>), also called '''sweetcorn''', '''sugar corn''', or simply '''corn''', is a variety of [[corn]] with a high [[sugar]] content. Sweet corn is the result of a naturally-occurring [[recessive]] [[mutation]] in the genes which control conversion of sugar to starch inside the [[endosperm]] of the corn kernel. Unlike [[field corn]] varieties, which are harvested when the kernels are dry and fully mature, sweet corn is picked when immature and eaten as a [[vegetable]], rather than a [[cereal|grain]]. Since the process of maturation involves converting sugar into [[starch]], sweet corn stores poorly and must be eaten, [[Canning|canned]], or frozen before the kernels become tough and starchy.

==History==
[[Image:YoungSweetCorn.jpg|thumb|Young sweetcorn]]
Sweet corn occurs as a spontaneous mutation in field corn and was grown by several [[Indigenous peoples of the Americas|Native American]] tribes. The [[Iroquois]] gave the first recorded sweet corn (called "Papoon") to European settlers in 1779.<ref>"Sweet Corn Production." Jonathan R. Schultheis, North Carolina Cooperative Extension Service,
[[North Carolina State University]]. Revised 12/94. [http://www.ces.ncsu.edu/depts/hort/hil/hil-13.html]</ref> It soon became a popular vegetable in southern and central states.

Commercial production in the 20th century saw the rise of the ''se'' (''sugary enhanced'') mutants, which are more suitable for local fresh sales, and in the 1950s the ''sh2'' (''shrunken-2'') gene was isolated that minimized production of the enzyme that converts sugar to starch.<ref>[http://www.news.uiuc.edu/II/03/0807/sweetcorn.html]"Supersweet sweet corn: 50 years in the making." Debra Levey Larson. ''Inside Illinois'' Vol. 23, No. 3, Aug. 7, 2003. University of Illinois at Urbana-Champaign news bureau.</ref> There are currently hundreds of varieties, with more constantly being developed.

==Anatomy==
[[Image:MatureSweetCorn.jpg|thumb|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''. The ear is covered by tightly wrapped leaves called the ''husk''. ''Silk'' is the name for the styles of the [[pistil]]late flowers, which emerge from the husk. The husk and silk are removed by hand, before boiling but not before roasting, in a process called ''husking'' or ''shucking''.

==Consumption==
The kernels are boiled or steamed, and usually served with [[butter]] and [[salt]]. In the UK, China, and Japan, they are sometimes used as a [[pizza]] topping. ''Corn on the cob'' is sweet corn cob that has been boiled, steamed, or grilled whole; the kernels are then bitten off the cob with the teeth or cut off the cob. ''Creamed corn'' is sweet corn served in a milk or cream sauce. Sweet corn can also be eaten as [[baby corn]].

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. See [[Corn nuts]]. A soup may also be made from the plant, called sweet corn soup. Reble, Reble, Reble.........

==Varieties==
{{Mergefrom|Super sweet corn|date=August 2007}}
[[Image:Truckbed of Corn.jpg|thumb|Sweetcorn that has not been husked yet, headed to Market.]]
''[[Shoepeg corn]]'' is a particularly small, white variety of sweet corn. Kernels that are allowed to mature to hard grains are used as seed corn or ground into corn flour.

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. Some older varieties are best when cooked within 30 minutes of harvest [http://www.burpee.com/jump.jsp?itemID=559&itemType=CONTENT_ARTICLE]. Despite their short storage life, many open pollinated varieties such as [http://www.burpee.com/shopping/product/detailmain.jsp?itemID=899&itemType=PRODUCT&RS=1&keyword=50864A Golden Bantam] remain popular for home gardeners and specialty markets, or are marketed as [[heirloom seed]]s. Although less sweet, they are often described as more tender and flavorful than hybrid varieties.

===Genetics===
There are several different genetic mutations responsible for various types of sweet corn. Early varieties, such as those used by American Indians, were the result of the mutant ''su'' ("sugary") [[allele]].<ref>"Sweet Corn Production." Jonathan R. Schultheis, North Carolina Cooperative Extension Service,
[[North Carolina State University]]. Revised 12/94. [http://www.ces.ncsu.edu/depts/hort/hil/hil-13.html]</ref> They contain about 5-10% sugar by weight. Another form of the same [[gene]], the ''se'' or "sugary enhanced" allele, was responsible for so-called "Everlasting Heritage" varieties, such as 'Silver Queen'. Varieties with the ''se'' alleles have a much longer storage life and contain 12-20% sugar.<ref>"Sweet Corn." [[Oregon State University]] Horticulture 233 webpage. [http://oregonstate.edu/dept/hort/233/sweetcorn.htm]</ref> Beginning in the 1950s, plant breeders at the [[University of Illinois at Urbana-Champaign]] began developing 'supersweet' varieties, which occur due to a mutation at another gene (the ''sh'' or "shrunken" gene).<ref>[http://www.news.uiuc.edu/II/03/0807/sweetcorn.html]"Supersweet sweet corn: 50 years in the making." Debra Levey Larson. ''Inside Illinois'' Vol. 23, No. 3, Aug. 7, 2003. University of Illinois at Urbana-Champaign news bureau.</ref>

All of the alleles responsible for sweet corn are [[recessive]], so it must be isolated from any field corn varieties 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 are on the same gene and do not need to isolated from each other. However, since ''sh2'' is a recessive allele on a different gene, supersweet varieties must be grown in isolation from other varieties to avoid cross-[[pollination]] and resulting starchiness, either in space (various sources quote minimum quarantine distances from 100 to 400 feet / 30.5 to 122 m) or in time (i.e. the supersweet corn does not pollinate at the same time as other corn in nearby fields).

In colder areas, a fourth type of sweet corn, known as ''sy'' (for ''synergistic''), is often grown. This variety of corn mixes ''se'' and ''sh2'' kernels on the same cob and does not require isolation.

==References==
{{Reflist}}

[[Category:Staple foods]]
[[Category:Cereals]]
[[Category:Grasses]]
[[Category:Tropical agriculture]]
[[Category:Native American cuisine]]
[[Category:Vegetables]]
[[Category:Maize]]

Sweetcorn - Revision history

Envoy at 15:32, 13 September 2007