EC86-112 Origins, Adaptation, and Types of Corn W

University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Historical Materials from University of Nebraska- Extension Lincoln Extension 1986 EC86-112 Origins, Adaptation, and Types of Corn W. L. Brown M. S. Zuber L. L. Darrah Follow this and additional works at: http://digitalcommons.unl.edu/extensionhist Brown, W. L.; Zuber, M. S.; and Darrah, L. L., "EC86-112 Origins, Adaptation, and Types of Corn" (1986). Historical Materials from University of Nebraska-Lincoln Extension. 4596. http://digitalcommons.unl.edu/extensionhist/4596 This Article is brought to you for free and open access by the Extension at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Historical Materials from University of Nebraska-Lincoln Extension by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Nebraska Cooperative Extension Service EC86-11 2 Origins, Adaptations, and Types of Corn I , '... .._.. '""'' io f"rth"'"" of Coop""'" E><•ooioo wmk, Ao" of M•v 8 >Od J""' 30, 191 4 , '" ""'""''" whh<h• ;~··, ....... U.S. Department of Agriculture. Leo E. Lucas, Director of Cooperativ e Extension Service, University of Nebraska, ; . · ~ Institute of Agriculture and Natural Resources. •• ••~ •.o " The Cooperativ e Ex tension Service provi.des inf ormation and educational programs to all people w ithout regard to race, color, national ortg1n . sex or h andic ap. Origins, Adaptation, and Types of Corn* W .L. Brown, Pioneer Hi-Bred International, Inc., lA; M .S. Zuber, University of Missouri; L.L. Darrah, USDA-ARS, University of Missouri; and D.V. Glover, Purdue University ORIGIN OF CORN if less attention were given to determining corn's ori Corn (Zea mays L. ) is the only important cereal gin and more to understanding the remarkable varia indigenous to the Western Hemisphere. Apparently bility found within the species. originating in Mexico, it spread northward to Canada and southward to Argentina . Wh ile the possibility of Variability and Races secondary centers of orig in in South America cannot Re gardless of origin, corn has proven to be one be completely ru led out, the oldest (7 000 years) ar of the most adaptable and variable members of the chaeological corn was found in Mexico's Va ll ey of grass family. Its evolution, a large part of which ap Tehuacan . parently occurred under domestication, has resu lted The earliest "corn" of wh ich there is record is un in biotypes with adaptation ranging from the tropics mistakably corn. The female inflorescence of th is to the north temperate zone, from sea level to 12,000 5000 B.C. corn had reached a degree of specializa feet altitude and growing periods (planting to maturi tion that precluded the possibil ity of natural seed dis ty ) extending from 6 weeks to 13 months . semination. Thus, the oldest corn of record was Almost 300 races of corn have been described dependent upon man for its survival . from Mexico, Central and South America, and the Numerous theories of origin have been offered Caribbean. Although many appear synonymous, at over the years, on ly two of which receive serious least 150 di st inct entities have been collected in consideration today. One is that teosin te (Zea mexi these areas . It was from certain of these races that cana ) is the wild progenitor of corn; the other is that most of the corns of North America were ultimately a wild pod corn, now extinct, was the ancestor of derived . domesticated corn While perhaps more students of corn seem to accept the first theory, others are Spread from Center of Origin equally convinced of the second . Following discovery, corn moved qu ickly to Eu Aside from its possible role in the origin of corn, rope, Africa and Asia . From Spain, it spread north eosinte has had major impact on its evolution. In ward to the short -growing -season areas of France. Mexico particularly, introgression between corn and Germany, Austria and eastern Europe, where selec teosinte has likely occurred for centuries and contin lion for early maturity has produced some of the ear ues to thi s day. The effects are apparent in the mor liest commercial vari eties of corn now avail able . In phology and cytology of both species. There is also Italy and Spain, early counterparts of man y South rea son to bel ieve that genes for re sistance to certain American races are evident even today . vi ruses have re ached corn through its introgression Although introduced into Africa soon after wi th teosinte . discovery, much of the corn now found in that con The origin of corn may never be known with cer tinent is derived from later introductions from the ta inty. One reason is that the hypotheses purporting southern U.S., Mexico and parts of eastern South to explain origin cannot be tested experimentally. America. Most of southern Africa's corn traces back Therefore, science would perhaps be better served to variet ies grown in the southern U S. in colonial *Contents reprinted f rom Nat ional Corn Handbook publication NCH-1 0. Contact Charles A . Francis, Extension Crops Specia list, for more information . 3 and post -colonial times. Corn of tropical middle The major environmental factors are: (1) daily (lowland) Africa is similar to the lowland and tropical maximum and minimum temperatures, (2) soil atmo corns of Central and South America . Africa has al sphere and moisture levels, (3) humidity of the atmo ways preferred white corns; and until recently, the sphere immediately surrounding the plant, (4) wind The most widely used and productive corns of movement, (5) day length, (6) light intensity, (7) air Asia are derived from Caribbean -type flints intro pollution, (8) soil type, (9) soil fertility, (1 0) number of duced in relatively recent times . However, older and days exceeding 50°F, (11) competition from other quite distinct types of corn can also be found, for ex plants including its intended neighbors as well as ample, among the hill people of Mindanao in south weeds, and (12) the disease-insect complex . ern Philippines . Included are some small-eared, Many of these factors interact in a complex early -maturing flints or pops that either have the manner to produce stress on the plant. The plant's capacity to grow and mature quickly before being reaction to stress is under genetic control, and devastated by downy mildew or carry some genetic differences among hybrids exist. Corn breeders are resistance to downy mildew. continuously developing and testing new genetic In the eastern Himalayas (Sikkim and Bhutan). a combinations in differing environments to find types distinctive type of popcorn is found whose Western that give the best agronomic performance over a Hemisphere progenitors seem to have disappeared . range of geographical locations and years. When and how the ancestor of th is corn reached Corn is grown from sea -level to altitudes of more Asia is not known . However, since it is not present than 12,000 feet and from the equator to about 50° on the Indian subcontinent to the south, it may have north and south latitudes. Compared to environ men reached the Himalayas by way of China and Tibet. tal conditions of the U.S. Corn Belt. many producing In any event, a search for similar corns in south Chi areas would be considered very much substandard . na and Tibet would seem justified. In harsh -environment areas. the varieties grown would be considered adapted because they Corn of the U.S. Corn Belt responded the best under the unfavorable growing Whereas most of the modern races of corn are conditions. The original open -pollinated varieties derived from prototypes developed by early native have become adapted through selection over time agriculturists of Mexico. Central and South America. by both man and the environment. one outstanding exception is solely the product of post -colonial North America-the yellow dent corns that dominate the U.S. Corn Belt, Canada and much Adaptation Within the Corn Belt of Europe today . The origin and evolution of this re World production of corn in the early 1980's ap markable race of corn have been clearly document proached 450 million metric tons annually, with the ed and confirmed . U.S. contributing over 48 percent of the total. Of U.S. In the early 1800's, two predominant races of annual production, the 13 Corn Belt states account corn of North America's eastern seaboard-the for about 82 percent . late -maturing Virginia Gourd seed and the early No area of the world equals the Corn Belt for high maturing Northeastern Flints-were first crossed, and yields . This is due to a combination of ideal soils and the superiority of the hybrid recognized and climate, advanced farmer know-how, and the suc described. The cross was repeated many times dur cess of corn breeders in developing hybrids with ing the western migration of settlers; and out of these high genetic potential. mixtures eventually emerged the Corn Belt dents, the Climate. Corn is considered a warm -weather most productive race of corn found anywhere in the crop. In the Corn Belt. average summer tempera world . tures range from 70° to 80° F daytime and exceed It was the highly selected varieties of Corn Belt 58° F at night. The average frost -free growing period dents that formed the basis of hybrid corn and the is over 140 days. Greatest yields are obtained where source of the first inbred lines used to produce hy 30 or more inches of rain occur during the growing brids . Germplasm from some of these varieties (Reid, season. In areas where rainfall is less than 20 Lancaster, Krug, etc.) still figure prominently in the inches, yields are much reduced unless irrigation is ancestry of hybrids used in the Corn Belt even to used.

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