Indiana soybean farmer Vernon Hugh Bowman, center, and his lawyer Mark P. Walters, left, speak to the media outside the Supreme Court on Feb. 19 following arguments in the case against global seed giant, Monsanto. (Jason Reed/Reuters)

The Supreme Court on Tuesday seemed ready to protect Monsanto’s patent rights in a dispute with an Indiana farmer over his planting of the company’s genetically modified soybeans.

The case involves the restrictions that Monsanto places on farmers’ use of a soybean it developed that is resistent to the herbicide Roundup. But the broader issue of patent protection is also important to the makers of vaccines, software and other products.

Questions from the justices during oral arguments indicated that they agreed with the contention of Monsanto and other companies that research and development would dry up if the companies’ patents were easily circumvented.

“Why in the world would anybody 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?” Chief Justice John G. Roberts Jr. asked.

The rest of the argument wasn’t much easier for Mark P. Walters, the attorney representing farmer Vernon Hugh Bowman.

Bowman’s case raises questions about whether the right to patent living things extends to their progeny. And it points out both the utility and ubiquity of Monsanto’s product, which its attorney, Seth Waxman, called “probably the most rapidly adopted technological advance in history.”

The farmer purchased Roundup Ready soybeans for his first planting of the year on the 300 acres he farms in southern Indiana. At the time of the purchase, he agreed he would not save seeds from the crop for future planting.

But he did buy commodity soybeans, which are usually used for feed, from the local grain elevator for a second planting. As he hoped, those beans were mostly Roundup Ready, because that’s what most of his neighbors grow. Monsanto said Bowman’s planting violated the company’s patent, and the U.S. Court of Appeals for the Federal Circuit agreed.

Walters said Monsanto’s right to control Bowman’s use of the seed ended when Bowman bought it, a legal concept called patent exhaustion.

“It is available to be used by the purchaser to practice the invention,” Walters said. “Now, the only way to practice that invention is to plant the seed and to grow more seeds.”

But several justices said that Bowman wasn’t just growing crops, he was manufacturing replicas of Monsanto’s patented seed.

“The exhaustion doctrine permits you to use the good that you buy,” Justice Sonia Sotomayor told Walters. “It never permits you to make another item from that item you bought. . . . You can use the seed, you can plant it, but what you can’t do is use its progeny unless you are licensed to, because its progeny is a new item.”

Walters replied that this was a new topic for the court — it has never considered applying the exhaustion doctrine to ­self-replicating technologies — and the court should not take it upon itself to create an exception. “You’re modifying this court’s case law substantially, and that’s something that ought to be done in Congress,” he said.

The Obama administration sided with Monsanto in the case and said Bowman’s position would “eviscerate” research.

“In order to encourage investment, the Patent Act provides 20 years of exclusivity,” said Assistant Solicitor General Melissa Arbus Sherry. “This would be reducing the 20-year term to essentially one and only sale. It would be near impossible to recoup your investments with that first sale and so the more likely consequence is that research dollars would be put elsewhere.”

The case is Bowman v. Monsanto .