Cultivation

Originally a tropical plant, maize (corn; zea mays) is grown today worldwide even in regions with a moderate climate (in 2007, maize occupied 157 million hectares). The USA provides about 40% of the world production. Other important producing countries are China, Brazil, Mexico, India, Nigeria, Indonesia, and Argentinia. According to the colour of the kernels, two types of maize are distinguished: yellow maize and white maize.

Utilisation

Maize, together with wheat and rice, is one of the world's most important food plants. In many southern countries, especially in central and southern America and Africa, maize plays a major role in nutrition. These countries have a wide variety of tradition maize products (e.g. tortillas, tacos).

Foodstuffs and ingredients:

• corn oil, corn flour used for baking and in snacks (tacos, corn puffs)
• cornflakes and other cereals
• alcoholic drink, such as beer

• starch and modified starch, including numerous products with sugar produced from starch

Animal feed:

• more than two thirds of the world's maize crop is used as animal feed (corn gluten, silage). In Germany in particular, maize is usually fed as silage. Here, the whole maize plant is chopped and fermented.

Energy crops, renewable primary products:

• maize as a source of energy: used in biogas facilities to produce heat and electricity, also used to produce biofuels (bioethanol)
  There are new breeds of maize that have been optimised to yield a high biomass. Such plants are noticeably larger, but up to now these ''energy'' maize plants have not been genetically modified.
• maize starch: used to produce "edible crockery"
• de-kerneled cob granules: oil-binding granules, litter for small animals
• maize plants: compostable packing material

Gene technology: aims of research and development

Agronomic traits

Weed control

• Herbicide tolerance, increasingly in combination with insect resistance

Resistance to pests

• Insect resistance: in particular through transfer of the gene for different Bt toxins. The maize plants gain resistance to pests such as the corn borer or maize root borer.

Adaptation to climate and location factors

• Drought resistance
  Approval for cultivation of drought tolerant maize is at present being processed in the USA.

• Tolerance to high salt and heavy metal levels in the soil

Plant development

• male sterility to help in the breeding of high-yield varieties (hybrids); usually together with tolerance to herbicides

• altered flowing time

Quality traits

Modified composition of components, use of maize as forage

• increased oil content and thus increased energy yields

• Enhanced proportion of the amino acids lysine and tryptophan as well as a reduction in the levels of the bitter-tasting sinapinic acid. An application for import and use as food and feed in the EU for a "high-lysine" maize (LY038-Maize) has been withdrawn.

• Production of the enzyme phytase in maize corns
  Aim: To improve the utilisation by swine and poultry of phosphate in the fodder, reduction in the phosphate burden in liquid manure and dung

• Raising the content of vitamin E

• Spanish scientists developed a genetically modified maize with increased content of carotenoids, vitamin C and folic acid.

Renewable primary products, energy crops

Production of energy

• Aim: better decomposition of maize starch and thus more efficiency in the production of bioethanol, making the current supplementation with a heat-stable alpha-amylase redundant. Approval for GM maize (3272-Maize) that can produce a heat-tolerant amylase is being processed in the EU.

Source of raw materials for industrial products

• Formation of certain starches and increased starch content, to produce new types of plastics from maize.

Production of pharmaceutically active substances

• Molecular pharming: utilisation of gene-modified maize as a system for producing technically and pharmaceutically useful enzymes

Field trials with GM maize

Utilisation of GM maize

* Among the approvals are five for new types of maize plants, bred by other procedures. These maize varieties are resistant to herbicides.
Such new types of plants require approval in Canada. In contrast, in the EU and the USA only genetically modified plants have to undergo the approval procedure, and not new breeds of plants produced, for example, by mutagenesis.