Corn was mixed as spillover support from higher soybeans and worries over rain-delayed US planting were largely offset by technical selling and profit-taking following seven straight sessions of gains that took prices to one-year highs.
Wheat retreated on technical selling and profit-taking after touching a three-month high on Tuesday.
Bloomberg reported on Tuesday that the White House was considering direct payments of $2 per bushel for soybeans and just 4 cents a bushel for corn to offset farmers' losses caused by the US-China trade war.
The report, which was seen encouraging more soy acres at the expense of corn, knocked soy prices down 1pc before the US Department of Agriculture (USDA) released a statement suggesting it was inaccurate.
"Soybeans are gaining back some of what they gave up yesterday. We bounced off technical support, which was very good," said Karl Setzer, market analyst with Agrivisor.
US soybean export prospects were also seen improving due to rising soybean prices in South America and better soy crush margins in China that indicate soybean demand from the world's top importer could rise, he said.
While China was not expected to buy US soybeans due to steep tariffs, Chinese buying of South American soy could steer other world buyers to the United States.
The USDA on Wednesday confirmed private sales of 131,000 tonnes of US soybeans to undisclosed buyers.
Chicago Board of Trade (CBOT) July soybean futures were 8-1/4 cents higher at $8.30-1/4 per bushel at 12:25 p.m. CDT (1725 GMT) after bouncing off of the prior day's low of $8.19.
July corn was down 1/2 cent at $3.93-3/4 a bushel while CBOT July wheat was down 3-1/2 cents at $4.75-1/4 a bushel.
The prospect of heavy rain expected this week in parts of the Midwest and Plains has rattled grain markets as it could compound corn planting delays after a soggy spring while also threatening to damage winter wheat in the run-up to harvesting.
The US Department of Agriculture said on Monday that a lower-than-expected 49pc of the US corn crop has been planted, the slowest pace on record, based on data going back to 1980.
Soybeans were 19pc planted, also short of market expectations.