UBS has called time on the bear market in grains, singling out corn as a crop whose "hidden surprises" left it open to a strong rebound in prices.

The investment bank said that it looked "increasingly likely" that crop prices had bottomed out, given their resilience in the face of a spate of bearish data.

"Corn, wheat and soy prices have retreated substantially, but have recently stopped falling," analyst Dr Thomas Gilbert said.

"This although the US Department of Agriculture continues to report record harvest yields... and as emerging markets showed meat consumption below the level of 2006-08.

"We see this as a sign that the bearish sentiment on soft commodities is getting tired."

'Ignite' prices 

Corn in particular looked open to a rally, given frost threats, growing ethanol use and drought damage which looked set to cut the harvest in China, the world's second biggest producer, by about 10% from last year's 166m tonnes.

Corn prices in the south of China had already jumped $30 a tonne above American prices, Dr Gilbert said, quoting data from FeedInfo.

"With stockpiles thousands of miles from the market, the risk for a need to import corn from the US has significantly increased," said.

Any foreign purchases by China, which was until 2003 Asia's biggest importer of the grain, could "ignite" Chicago prices.

"China's almost set-in-stone self-sufficiency in corn is suddenly under scrutiny," he added.