Corn rallied on speculation a slump to the lowest level in 34 months may spur demand before the U.S. Department of Agriculture updates its production estimates.

Corn for December delivery climbed as much as 0.7 percent to $4.6225 a bushel on the Chicago Board of Trade and was at $4.6025 by 1:41 p.m. in Singapore. Prices dropped to $4.55 yesterday, the lowest since since Oct. 4, 2010.

The grain tumbled 34 percent this year, the second-worst performer on the Standard & Poor’s GSCI Spot Index of 24 commodities, as the USDA predicts domestic output will rebound to a record. The government is set to release net export sales data tomorrow and update its output forecasts, based on farmer and field surveys, on Aug. 12.

“The low of $4.55 should act as a support level,” said Faiyaz Hudani, an analyst at Kotak Commodity Services Ltd. “A relief rally for a week or so may be witnessed, it depends on how the USDA data comes on Monday. If the data is a little bit supportive, we’re looking at a bounce back.”