(Reuters) - U.S. agribusiness Archer Daniels Midland (>> Archer Daniels Midland Company) did not submit a final bid for Canadian grain company Viterra (>> Viterra Inc) after deeming the cost of an acquisition "would not meet our return objectives," ADM CEO Patricia Woertz said on Tuesday.

Commodities trader Glencore (>> Glencore International Plc) agreed to buy Viterra on Tuesday in a cash deal valuing the company at C$6.1 billion ($6.2 billion).

ADM had been widely rumored to be among a short list of buyers interested in Viterra after the Canadian company said two weeks ago that it received expressions of interest from third parties.

An acquisition would have given Decatur, Illinois-based ADM greater access to Canadian crops to meet growing global demand, particularly from Asia, just as the Canadian Wheat Board's 69-year monopoly on Western Canadian wheat and barley was slated to end later this year.

Major grain companies have sought to expand operations in Western Canada since Ottawa voted last year to end the world's last remaining grain monopoly, freeing up business opportunities.

In the 2010/11 marketing year, the Canadian Wheat Board exported 17.41 million tons of wheat, durum, and barley and pulled in a revenue of C$5.8 bln from export and domestic sales. Canada is the world's No. 8 grain producer and a leading exporter of spring wheat, canola, oats and durum.

"We identified substantial synergies of a combined business," Woertz said in a statement.

"However, we determined that at the valuation level we anticipated to be competitive, which has been confirmed by the announced deal, the acquisition would not meet our return objectives. We chose not to submit a final bid."

ADM shares on the New York Stock Exchange were little changed at midday on Tuesday at $31.70 each.

(Reporting by Karl Plume in Chicago; Editing by Philip Barbara)

By Karl Plume