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 skyrocket. Corn seed prices rose 32 percent; soybean seeds were up 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, which 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 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.

On Friday, as the spring planting season approaches, Eric H. Holder Jr., the attorney general, and Tom Vilsack, the agriculture secretary, 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 L. 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 dominance. The company’s genetically engineered traits are in the vast majority of corn and soybeans grown in the United States, Mr. Miller said. “That gives them considerable power, and questions arise about how that power is used,” he said.