Monsanto is to charge farmers up to 42% more for cutting-edge seeds than the first-generation genetic equivalents as it restated it was on course to double operating profits.

The US agribusiness giant said farmers would pay $74 an acre for so-called Roundup Ready 2 Yield soybean seed, which are resistant to the herbicides growers use to take out general weeds, and are expected to be sown on 7-8m acres in the US next year.

The first-generation Roundup Ready seeds, which offer a less advanced range of genetically modified traits, will cost $52 an acre, the company said.

For corn, the seeds and chemicals giant will charge farmer the equivalent of $130 an acre for its so-called called Genuity SmartStax seeds, which include genes protecting plants against herbicides and insect pests, and are expected to be launched in the US next year.

The existing YieldGard VT Triple product will cost $111 an acre.

'Inflationary increase'

A Monsanto spokesperson told Agrimoney.com that the price difference between soybean seed types was only marginally wider than that charged to farmers this year, when conventional Roundup Ready cost $49-52 an acre.

A rise of $2-5 per acre in the cost of Roundup Ready 2 Yield reflected an "inflationary increase".

The new SmartStax corn seeds were not available in the latest planting season.

'Technology explosion'

The prices were revealed as Monsanto heralded a "technology explosion" in its seeds range, backed by the group's "most robust pipeline ever".

Hugh Grant, the Monsanto chief executive, said: "We have committed to using our technology to double yields in our three core crops - corn, soybeans and cotton - by 2030.

"Innovation has us well on our way to achieving this."

The forthcoming product lines, which also include drought-tolerant corn and crops better at using nitrogen, would generate at least $3bn of sales a year between them by 2020.

Mr Grant added that Monsanto was on track to double gross profit between 2007 and 2012, driven by expansion in seeds, with profits from the herbicides division pegged at $1bn.

Monsanto shares stood 2.3% higher at $84.36 in afternoon trade in New York.