(Reuters) - Shrinking arable land, volatile weather and a world population tipped to surpass 9 billion by 2050 are fuelling calls to deploy high-yielding genetically altered crops to ensure food security.
Yet deep-seated fears that genetically modified organisms (GMO) pose risks to public health mean cultivation of these crops remains restricted in several key regions, including major farming power houses China and India.
GMO advocates, however, maintain that health fears are not scientifically proven and that poor farmers are in fact likely to benefit most from these crops.
GMO crops have their DNA modified to make them resistant to pests, diseases and adverse climate conditions, the latter being of immediate relevance given the El Nino weather pattern last year that led to droughts and crop damage.
Annual global corn output has more than doubled to nearly 1 billion tonnes from 425.6 million tonnes in 1980 when the world started embracing GMO products. For soybeans, output has jumped nearly two-and-half times to 319 million tonnes over the period.
Corn yields in Brazil, where GMOs are widely planted, have risen 60 percent in the past decade, versus a growth of only 11 percent and 20 percent in China and India that bar the cultivation of GMO food crops.
The United States is the world leader in GMO research and production, and home to sector major Monsanto Co (MON.N).
Much of corn and soybean production in the United States, Brazil and Argentina, which together account for more than 80 percent of soybean output and nearly half of the corn output, are genetically modified.
Last year, a report by a World Health Organisation group classified the chief ingredient in Monsanto's herbicide Roundup as "probably carcinogenic to humans". Monsanto has denied the claim.
U.S. health regulators have recently approved a type of genetically engineered Atlantic salmon for human consumption - the first such approval for a biotech animal.
China, Japan and South Korea import GMO corn and soybeans for animal feed, while Indonesia is among the few to import GMO soybeans for human consumption.
The Philippines is a big buyer of GMO soymeal and is set to issue new rules on GMO purchases, seeking to avert supply disruptions when a court-ordered stoppage kicks in as import permits for animal feed expire.
In production, lab-grown seeds yield nearly all of the cotton in India, the world's top producer.
Vietnam, one of Asia's fastest growing feed grain markets, last year allowed the cultivation of GMO corn.
However, GMO food crops have not gained any foothold in China and India.
While China has signalled a willingness to embrace GMOs over the longer term following state-owned ChemChina's $43 billion bid for seed and agri-chemical producer Syngenta SYNN.VX, in India popular opinion remains against the cultivation of GMO food crops.
EUROPE ON GMOs
Most European nations do not produce GMOs. France, the bloc's largest grain grower, has banned Monsanto's MON810 maize strain since 2008.
France was among the first countries to use a new European opt-out scheme to ensure a ban on the cultivation of GMO crops, followed by other maize growers Italy, Hungary and Germany.
Many African countries have banned GMO crops, with the exception of South Africa producing GMO maize on a commercial scale.
But a scorching drought that led to widespread crop failure is changing perceptions, with Burkina Faso in West Africa and lately Sudan having started to grow GMO cotton commercially.
Reporting by Naveen Thukral in SINGAPORE; Editing by Himani Sarkar