Front-month Chicago Board of Trade corn for September delivery climbed 16.75 cents, or 3.9%, to $4.4975 per bushel, while the December contract, the most active, climbed 17 cents to $4.645.

Friday's catalyst was a mid-morning report from Informa Economics, a Memphis agricultural consultant and research firm, that projected a final 2010 U.S. corn yield of 158.5 bushels per acre, traders said. That would be down from the U.S. Department of Agriculture's most recent estimate of 165 bushels per acre.

The forecast reaffirmed an emerging view in the industry that the crop will be weaker than first expected. Farmers and analysts say the crop is highly variable after a soggy summer that flooded out low-lying areas of many fields and washed away nitrogen, a crucial nutrient for corn. Hot night-time temperatures have also deprived the crop a chance to "rest" analysts say.

A yield around 160 bushels per acre would lead to uncomfortably tight supplies for the U.S. market, which has been presumed to be a growing exporter because of drought-ravaged Russian crops. The drought in Russia and crop troubles in other parts of the world have sent grains and oilseeds sharply higher the past two months.

"The U.S. was supposed to be this 'island of supply,'" said Dan Basse, president of AgResource Co., an agricultural research firm. "We're now starting to question that."

Informa's projections are watched closely because they represent "probably the most heavily funded private crop survey," Basse said. Some analysts say that Informa has a reputation for issuing bearish crop projections, which made Friday's estimate all the more surprising.

The market's rally to its highest price since October 2008 triggered some pre-established buy orders, and attracted a wave of speculative fund money, traders added. Funds bought an estimated 25,000 contracts, a sign of significant outside money flow, traders said.

With the market's continued surge, livestock producers, who need corn for feed, are starting to question whether they need to buy more corn before prices rally even higher, said Jason Britt, president of Central State Commodities, a Kansas City brokerage. He said that "some nervousness has crept in."

Wheat and soybeans also continue to surge. Chicago Board of Trade wheat for December delivery gained 27.5 cents, or 3.9%, to $7.4125 per bushel and November soybeans gained 26 cents, or 2.6%, to $10.35.

The USDA will release updated production figures on Sept. 10. Traders said the agency is often conservative in changing its crop projections, and Informa, despite its own bullish outlook, only expects the USDA to lower its corn yield estimate to 164.8 bushels per acre next week.