During the depths of the economic crisis last year, the prices for many goods held steady or even dropped. But on American farms, the picture was far different, as farmers watched the price they paid for seeds jump. Corn seed prices rose 32 percent, soybean seeds 24 percent.

Such price increases for seeds — the most important purchase a farmer makes each year — are part of an unprecedented climb that began more than a decade ago, stemming from the advent of genetically engineered crops and the rapid concentration in the seed industry that accompanied it.

The price increases have not only irritated many farmers, they have caught the attention of the Obama administration. The Justice Department began an antitrust investigation of the seed industry last year, with an apparent focus on Monsanto, the company that controls much of the market for the expensive bioengineered traits that make crops resistant to insect pests and herbicides.

The investigation is just one facet of a broader push by the Obama administration to take a closer look at competition — or the lack thereof — in agriculture, from the dairy industry to livestock to commodity crops, like corn and soybeans.

Today, as the spring planting season approaches, Attorney General Eric Holder and Agriculture Secretary Tom Vilsack will speak at the first of a series of public meetings aimed at letting farmers and industry executives voice their ideas. The meeting, in Ankeny, Iowa, will include a session on the seed industry.

“I think most farmers would look to have more competition in the industry,” said Laura Foell, who raises corn and soybeans on 900 acres in Schaller, Iowa.

The Iowa attorney general, Tom Miller, has also been scrutinizing Monsanto’s market dom- inance. The company’s genetically engineered traits are in the vast majority of corn and soybeans grown in the United States, Miller said. “That gives them considerable power, and questions arise about how that power is used,” he said.

Critics charge that Monsanto has used license agreements with smaller seed companies to gain an unfair advantage over competitors and to block cheaper generic versions of its seeds from eventually entering the market. DuPont, a rival company, also claims Monsanto has unfairly barred it from combining biotech traits in a way that would benefit farmers.

Monsanto’s response

In a recent interview at Monsanto’s headquarters in St. Louis, its chief executive, Hugh Grant, said that while his company might be the market leader, competition was increasing as the era of biotech crops matured.

“We were the first out of the blocks, and I think what you see now is a bunch of people catching up and aggressively competing, and I’m fighting with them,” Grant said. He said farmers chose the company’s products because they liked the results in the field, not because of any untoward conduct on Monsanto’s part.

Yet, in a seed market that Monsanto dominates, the jump in prices has been nothing short of stunning.

Including the sharp increases last year, Agriculture Department figures show that corn seed prices have risen 135 percent since 2001. Soybean prices went up 108 percent over that period. By contrast, the Consumer Price Index rose only 20 percent in that period.

A Monsanto spokesman, Lee Quarles, said the price increases were justified because the quality of the seeds had been going up, and new biotech traits kept being added. For example, he said, many corn varieties now include multiple genes to battle insect pests, raising their value.

Quarles said higher prices were justified because the traits saved farmers money and made their operations more efficient.

Monsanto began investing heavily in biotechnology in the 1980s — ahead of most other agricultural companies. In the mid-1990s, it became the first to widely market genetically engineered seeds for row crops, introducing soybeans containing the so-called Roundup Ready gene, which allowed plants to tolerate spraying of its popular Roundup weed killer. Soon after, it began selling corn seed engineered with a gene to resist insect pests.