By Virginia Gewin
Corn is one of humankind's earliest innovations. It was domesticated
10,000 years ago when humans learned to cross-pollinate plants and slowly
turned a scraggly nondescript grass called teosinte into plump, productive
modern corn. As needs change, so does plant breeding. Today, while biotech
super-giants manipulate corn genetics to satisfy farmer desires and a global
market, indigenous Mexican farmers do so to fulfill individual needs.
Although the tools differ, the goal remains the same-to cultivate desirable
traits. Over time, selective breeding modifies teosinte's few fruitcases
into modern corn's rows of exposed kernels.
Plant breeding was once restricted to sexually compatible plants, and
generations of offspring were selectively bred to create unique varieties.
In fact, corn, along with rice and wheat-today's global crop staples-would
not exist without such techniques. With the goal of ever-widening the pool
of genetic diversity, conventional plant breeding has gotten more
technologically savvy in recent years. For example, realizing that natural
mutants often introduce valuable traits, scientists turned to chemicals and
irradiation to speed the creation of mutants. From test-tube plants derived
from sexually incompatible crosses to the use of molecular genetic markers
to identify interesting hereditary traits, the divide between engineering
and genetics was narrowing long before kingdom boundaries were crossed.

But when geneticists began to explore microorganisms for traits of
interest-such as Bacillus thuringiensis (Bt) genes that produce a protein
lethal to some crop pests-they triggered an uproar over ethical, scientific,
and environmental concerns that continues today.


Despite such discord, genetically modified (GM) crops have the fastest
adoption rate of any new technology in global agriculture simply because
farmers benefit directly from higher yields and lowered production costs. To
date, the two most prevalent GM crops traits are Btderived insect resistance
and herbicide resistance.

Since 1987, over 9,000 United States Animal and Plant Health
Inspection Service (APHIS) permits have been issued to field-test GM crops.
According to APHIS, corn is the most tested plant. The International Service
for the Acquisition of Agri-Biotech Applications confirms that biotech corn
is the second-most common GM crop (after soybean), with 12.4 million
hectares planted in 2002. GM corn starch and soybean lecithin are just two
of the ingredients already found in 70% of the processed food supply.

With future incarnations on the horizon, GM corn remains a lightening
rod for debate. Embroiled in numerous controversies, corn has become
biotech's boon and bane.

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