The biology of Zea mays L. (Corn/Maize).

  • Canada. Interdepartmental Executive Committee on Pest Management.
Date:
1994
Catalogue details

Licence: In copyright

Credit: The biology of Zea mays L. (Corn/Maize). Source: Wellcome Collection.

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    plants of this species with no novel traits. Novel traits of concern might confer new characteristics to the plant, that could impact on the environment pursuant to their unconfined release. Part B - The Biology of Zea mays B1.0 General Description, Cultivation, Use as a Crop Plant and Hybrid Production Zea is a genus of the family Graminae (Poaceae), commonly known as the grass family. Maize (Zea mays L.) is a tall, monecious annual grass with overlapping sheaths and broad conspicuously distichous blades. Plants have staminate spikelets in long spike-like racemes that form large spreading terminal panicles (tassels) and pistillate inflorescences in the leaf axils, in which the spikelets occur in 8 to 16 rows, approximately 30 long, on a thickened, almost woody axis (cob). The whole structure (ear) is enclosed in numerous large foliaceous bracts and a mass of long styles (silks) protrude from the tip as a mass of silky threads (Hitchcock and Chase, 1971). Pollen is produced entirely in the staminate inflorescence and eggs, entirely in the pistillate inflorescence. Maize is wind pollinated and both self and cross pollination are usually possible. Shed pollen usually remains viable for 10 to 30 minutes, but can remain viable for longer durations under favorable conditions (Coe et al., 1988). Cultivated maize is presumed to have been derived from teosinte (Z. mexicana) and is thought to have been introduced into the old world in the sixteenth century. Maize is cultivated worldwide and represents a staple food for a significant proportion of the world’s population. No significant native toxins are reported to be associated with the genus Zea (International Food Biotechnology Council, 1990). Cultivation and Use. Maize has been cultivated by the indigenous peoples of North America, including Canada, for thousands of years. The modem era of maize hybrid production in Canada began in the U.S. where research conducted in the early part of this century proved that hybrid maize could produce a yield superior to open- pollinated varieties (Sprague and Eberhart, 1977). Gradually, hybrid-derived varieties replaced the open-pollinated types in Canada in the 1930’s and 1940’s. In Canada, maize is grown primarily in Ontario and Quebec. Farmers must purchase new supplies of hybrid seed each season. Maize is planted when soil temperatures are warm (2 10°C) usually early to mid-May in southern Ontario (OMAF, 1994) and Quebec (MAPAQ, 1984). Optimum yields occur when the appropriate hybrid maturity and population density are chosen. In addition, exogenous sources of nitrogen fertilizer are generally applied and weed and insect control measures are generally recommended. Choice of the appropriate hybrid for the intended growing area helps to ensure that the crop will mature before frost halts the growth of the plant at the end of the season; hybrids are categorized 2 Regulatory Directive - Dir94-11 |
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