Monsanto, which debuted Roundup Ready in 1996 and now supplies 90 per cent of the United States' 275,000 soybean farms, disagrees. In 2007 the company accused Bowman of violating its patent, and filed a lawsuit.
Last week, Bowman v Monsanto Co arrived in the US Supreme Court, a test case for GM seeds and intellectual property (IP) law.
Bowman is not the only US farmer to cross swords with Monsanto. A Centre for Food Safety (CFS) report, Seed Giants vs US Farmers, says the world's largest seed company had filed 144 seed patent infringement lawsuits against farmers up to January this year. In what are often David versus Goliath IP struggles, thousands of disputes were settled out of court.
Bowman's is the first to reach the US' highest court. The case has provoked huge interest among food-safety lobbies, IP advocates and anti-trust groups, and is expected to have wide-reaching implications for agriculture, computer software, medical research and any other sectors determined to exert patent rights over self-replicating technologies.
The Obama Administration backs Monsanto's case; hardly surprising as IP dominates the US economy. A US Commerce Department report last year, Intellectual Property and the US Economy, found IP represented 34.8 per cent of gross domestic product, generating more than $6 trillion and 40 million jobs.
Monsanto's lawyer, Seth Waxman, told the Supreme Court his client's GM product was "probably the most rapidly adopted technological advance in history". The pro-Monsanto camp argues that protecting IP is crucial if innovators are to benefit and fund research.
Chief Justice John Roberts seemed to agree: "Why in the world would anyone spend any money to try to improve the seed if, as soon as they sold the first one, anybody could grow more and have as many of those seeds as they want?"
But the notion that patents, rigorously enforced by the US, are vital to research is not universally accepted.
"Most major new crop varieties developed throughout the 20th century owe their origin to publicly funded agricultural research and breeding," the CFS report notes.
Opponents stress "patent exhaustion", arguing Monsanto's control over its seeds ended with the first sale, a standard condition with patents. The law says buyers cannot copy a patented item. Bowman's lawyers have argued he was using, not copying, Monsanto seeds. But what if the item copies itself? Should patents apply to the progeny of living things?
"If you go down that road it gets ridiculous pretty fast," says Jaydee Hanson, senior policy analyst with the CFS, which has filed documents in support of Bowman. "If I keep a yoghurt culture do I owe the company that developed the culture? Under Monsanto's theory I would."
The Supreme Court case, and a dispute about patenting human genes set for April, also highlights conflict between IP and antitrust advocates.
Whereas IP laws grant exclusive property rights, antitrust laws favour competition. Bert Foer, president of the American Antitrust Institute, believes the US leans towards IP monopolies that favour patentees over consumers.
"We're moving towards a situation where staple foods are going to be subject to a patent-based chokehold throughout the world for both consumers and farmers." Deals such as the Trans-Pacific Partnership Agreement, which promote patents and economic "efficiencies", erode competition, he warns, raising the risk of catastrophic market failures.
For decades GM companies have insisted they will increase crop yields and feed the world's growing population. So far there is scant evidence GM foods, the latest being golden rice, are any more productive than conventional crops. Boosters also insist GM crops will be more drought tolerant and reduce carbon emissions.
But concerns about GM food safety and environmental threats persist even as GM companies rake in huge profits.
Traditionally, farmers could save seeds to replant. This is illegal with patented seeds. At the same time conventional seeds are vanishing from the market as GM companies patent global supplies once in public hands.
As 86 per cent of corn, 88 per cent of cotton and 93 per cent of soybean seeds used in US agriculture are genetically modified, the cascade of effects - for corporate profits and farming costs - is substantial.
Critics argue GM companies want to monopolise seeds so they can boost herbicide and pesticide profits. A Washington State University study last year found farmers growing GM corn, cotton and soybeans used about 25 per cent more glyphosate-based herbicides such as Monsanto's Roundup.
At the same time many weeds have become resistant to glyphosate. A Environmental Science Europe paper last year estimates "super weeds" infest between 20 and 25 million ha of American farmland.
Biotech companies are developing more potent herbicides. "They're moving to dicamba, which is more powerful, and one of two herbicides used in Agent Orange [the defoliant used in the Vietnam War, resulting in dire health issues for many combatants and civilians]," says Hanson.
Industrial agriculture's reliance on petrochemicals also locks farmers into dependence on fossil fuels, worsening climate change, say critics. Nonetheless, signs indicate Monsanto will prevail against Bowman.
Meanwhile, GM opponents are fighting genes with genes, using DNA sequencing to test food products. Research in New York last December by conservation group Oceana found seafood was widely mislabelled - 94 per cent of fish sold as tuna was not tuna - a potential fraud that evokes Europe's horse meat scandal.
