CME Group, owner of the Chicago Board of Trade (CBOT), will launch its long-planned European Union wheat futures in September as it challenges Euronext in the world's biggest wheat production zone.

CME has been working on an EU wheat contract for several years to add to its U.S. futures, which are a global benchmark. But it has faced hurdles in getting French grain silo operators to agree to act as delivery points.

The U.S. exchange will kick off trading in EU wheat futures and options on Sept. 12, with the new products to be listed on the CBOT, it said in a statement on Monday.

The EU contract will be denominated in euros, physically deliverable in France and priced in relation to Rouen, the northern French port that is the EU's biggest grain terminal, in line with draft versions previously reported by market sources.

"We're committed to making this work," Jeffry Kuijpers, CME's executive director, agricultural commodities, said on a call with reporters. "It took us a while to do the due diligence. We wanted to get it right, not fast."

CME currently has so far secured five partners with 12 silos and is in talks with another three firms to add a further five stores, which would bring its delivery capacity to around 500,000 tonnes, he said.

The silos will be at inland locations across northern France, in contrast to Euronext's port-based system, and users will have the choice of taking direct delivery of grain or holding on to certificates for deferred delivery.

The delivery model is at the heart of CME's pitch to European traders, who have been critical of Euronext's reliance on a small number of port silos for delivery against its milling wheat futures, the current price benchmark in Europe.

A rain-hit French harvest two years ago fuelled interest in CME's rival project as Euronext's port silos imposed extra quality requirements, causing confusion in the market.

Euronext said on Friday that its delivery silos would keep these extra requirements next season, with heavy rain again threatening grain quality in this year's harvest.

CME will offer December 2016 as the first delivery position available for trading.

Quality specifications will include minimum levels of 10.5 percent for protein and 170 for Hagberg falling numbers, both measures of the flour-making quality of wheat.

Euronext's contract does not currently have such specifications but will add from next year a minimum protein content of 11 percent and 220 seconds for Hagberg numbers.

CME said the listing of its EU wheat derivatives on the CBOT will allow investors who already trade U.S. grain futures to offset margin requirements. It will also offer a six-month fee holiday to try and generate liquidity.

Reporting by Gus Trompiz, Sybille de La Hamaide and Valerie Parent; Editing by Mark Heinrich.