CHICAGO (Dow Jones)--U.S. corn futures are expected to open slightly weaker Friday following overnight losses as concerns about the global economy and demand hang over the market.

Chicago Board of Trade futures are called 1 cent to 2 cents lower. In overnight trade, July corn was down 2 cents to $3.60 per bushel and December corn was down 2 3/4 cents to $3.75 3/4.

Sliding equities and crude oil, along with a stronger dollar, have pressured corn and continued to do so overnight. While the dollar has slid lower Friday morning, the overall macroeconomic picture is bearish, analysts say.

"Overall, the state of the world economy is slowing down, which slows down trade," said Don Roose, president of U.S. Commodities in West Des Moines, Iowa.

In addition to the bearish world economic outlook, Roose added that the possibility of slowed shipments out of the U.S. Gulf due to the massive oil spill there could start to weigh on trade.

But there is a firm bid by end-users under the market, export sales have been solid, and farmers are not selling, Roose added.

The climbing export demand, highlighted by recent buying by China and speculation about more purchases, has been the key supportive feature in the market.

A warming trend expected in the U.S. Corn Belt over the next several days is seen as bearish, as it will accelerate emergence and aid farmers who have yet to plant.

Heading into Friday's trade, July corn is down one cent on the week. Last week's close of $3.63 has been this week's high, but analysts said the market's late surge Friday was a good sign for bulls.

"It would be presumptuous to say that the seasonal low is behind us, but traders took note of the ability of corn prices to hold the line against stiff head winds," Farm Futures senior editor Bryce Knorr said in a commentary.

The next downside price objective for the bears is to push and close prices below solid technical support at the April low of $3.51 1/2, a technical analyst said. Bulls' next upside price objective is to push and close prices above solid technical resistance at $3.70 a bushel.

First resistance for July corn is seen at this week's high of $3.64 1/2 and then at $3.68, the technical analyst said. First support is seen at $3.60 and then at $3.57.

"It feels like we're in a transition period, waiting for a catalyst," Roose said.

-By Ian Berry, Dow Jones Newswires; 312-341-5778;