Chicago Board of Trade corn futures eased due to lower than expected weekly export sales reported by the U.S. government during the CME Group's newly expanded 21 hour trading cycle launched on Monday.

"Corn was weaker, everyone was a little disappointed in the export sales. Corn broke a little but everything else was about unchanged," a CBOT floor trade source said.

CBOT corn for July delivery was up 2-1/2 cents per bushel before the report was released at 7:30 a.m. CDT (1230 GMT) and turned down to nearly unchanged following the release of the report. USDA reported U.S. corn export sales last week at 482,100 tonnes versus trader estimates for 1,000,000 to 1,300,000 tonnes

Exchange operator CME Group plans to apply for federal approval on Thursday to extend its open-outcry grain trading session, ensuring its raucous Chicago pits will be in full swing before the next major U.S. agricultural report in June, grain traders said after a private meeting with CME officials.

Executive Chairman Terrence Duffy said at a media conference after its annual shareholder meeting on Wednesday that CME had no objections to extending pit grain trading if floor traders supported the move.