Maize, or corn, is a cereal grain, the kernel of which is largely
refined into products used in a wide range of food, medical, and
Maize is a member of the Maydeae tribe of the grass family,
Poaceae. It is a robust monoecious annual plant, which requires the
help of man to disperse its seeds for propagation and survival.
Corn is the most efficient plant for capturing the energy of the
sun and converting it into food, it has a great plasticity adapting
to extreme and different conditions of humidity, sunlight,
altitude, and temperature. It can only be crossed experimentally
with the genus Tripsacum, however member species of its own genus
(teosinte) easily hybridise with it under natural conditions.
Zea mays is an allogamous plant that propagates through seed
produced predominantly by cross-pollination and depends mainly on
wind borne cross-fertilisation. The interaction between
domesticated plants and their wild relatives can lead to
hybridisation and in many cases to gene flow of new alleles from a
novel crop into the wild population. Some teosinte species can
produce fertile hybrids with maizeand it has been documented that
maize and teosinte often interact, particularly with Zea mays ssp.
mexicana. Also, the known distribution of teosintes, together with
high likelihood of the presence of land races in the maize
production areas of Mexico indicates that there exist high
probabilities of genetic exchange between conventional maize, land
races and teosinte. Out-crossing of maize with Tripsacum species is
not known to occur in the wild.
Another factor to take into account regarding gene flow is the
exchange of seed and traditional maize improvement practised by
peasant communities and small farmers. Rural communities are open
systems where "...there is a constant flow of genetic material
among communities over large areas." therefore, as in the case of
Mexico, "...a land race variety, an improved variety, or a
transgenic variety of maize, can reach any zone of the country,
even the most isolated ones, such as those where teosinte grows."
The human factor together with the changes in policy and strategies
in maize production may increase several fold the chance of gene
flow between improved maize, teosinte and landraces.
Human consumption of corn and cornmeal constitutes a staple food in
many regions of the world. However, only a small amount of
whole maize kernel is consumed by humans. Maize is widely
cultivated throughout the world, and many forms of maize are used
for food, including Flour corn (subsp. mays Amylacea Group),
Popcorn (subsp. mays Everta Group), Dent corn (subsp. mays
Indentata Group), Flint corn (subsp. mays Indurata Group),
Sweetcorn (subsp. mays Saccharata Group), Waxy corn (ceratina
Kuleshov) and Pod corn (var. tunicata Larrañaga ex A. St.
The grain also has many industrial uses, including transformation
into plastics and fabrics. Some is hydrolyzed and enyzmatically
treated to produce sweeteners (such as high fructose corn syrup),
and some is fermented and distilled to produce grain alcohol,
including ethanol. Refined maize products, sweeteners, starch, and
oil are abundant in processed foods such as breakfast cereals,
dairy goods, and chewing gum.