SAO PAULO: Brazilian cotton producers in the state of Mato Grosso plan to file a lawsuit requesting cancellation of a patent protection related to Bayer AG's Bollgard II RR Flex genetically modified cotton seed, newspaper Valor Econômico reported on Thursday.

The news report said farmers in the Mato Grosso Cotton Producers Association (AMPA) will allege that the genetically modified seed does not constitute a de facto technological innovation. Mato Grosso soybean farmers used a similar argument when they sued in Brazil to cancel patent rights over the widely used Intacta RR2 PRO seed.

Sidney Pereira de Souza Jr., the attorney representing the farmers, could not provide an immediate comment.

In a statement on Thursday, Bayer said it had not been formally notified of any patent dispute related to the Bollgard II RR Flex technology. Bayer noted that this cotton seed technology was quickly adopted by Brazilian cotton growers, and was the most used in Mato Grosso.

Valor quoted AMPA as saying they will request a refund of $150 million worth of royalties they have already paid for use of the technology.

The farmers association did not provide an immediate comment.

Bollgard II RR Flex combines resistance to insects and weed-killers. The technology was developed by US-based Monsanto, a company taken over by Germany's Bayer in a $63 billion transaction.

No binding ruling has been issued in relation to the Intacta patent dispute, a Bayer spokeswoman said by telephone.