(Recasts, updates with closing prices, adds new analyst quote)
CHICAGO, Oct 25 (Reuters) - Chicago Board of Trade wheat futures eased on Wednesday on a round of profit taking after prices firmed to 2-1/2 week highs during the session.
"The wheat market has had trouble with the 50-day moving average since the middle of September, and today was no different," Charlie Sernatinger, global head of grain futures at ED&F Man Capital, said in a note to clients. "We keep trying to break through the 50-day moving average, and we keep failing."
Corn futures also closed lower after staking out fresh highs amid reports of farmers booking sales on the cash market when the market peaked.
Soybeans ended flat after technical selling pulled prices from their session top.
Chicago Board of Trade soybeans for November delivery were unchanged at $9.75-1/2 a bushel.
CBOT December corn was 1-3/4 cents lower at $3.51 a bushel. The contract hit its highest since Oct. 2 earlier in the session.
A huge short position by speculators underpinned corn prices as traders have been stepping in to unwind bearish bets at session lows this week.
CBOT December wheat was 2-1/2 cents lower at $4.35-1/2 a bushel. Wheat prices retreated from 2-1/2-week high.
But some concerns about the Australian crop limited the declines.
"Wheat could be getting some background support from problems with the Australian harvest but the overall plentiful supply picture globally could limit rises," said Matt Ammermann, commodity risk manager at INTL FCStone.
Australia's wheat farmers face a double blow this year as dry weather slashes local production at a time when bloated global inventories are dragging on international prices for the grain. (Additional reporting by Michael Hogan in Hamburg and Naveen Thukral in Singapore; Editing by Meredith Mazzilli and Susan Thomas)