Soybeans gained more ground as the market was supported by expectations of a trade deal between Washington and Beijing.
The Chicago Board of Trade (CBOT) most-active corn contract rose 0.4 percent to $3.63-1/4 a bushel by 0243 GMT, after gaining 1.5 percent on Monday.
Soybeans gained 0.6 percent to $9.00-1/2 a bushel and wheat added 0.3 percent to $4.64-1/4 a bushel.
"Flooding from cyclone and rains across U.S. Midwest are threatening to disrupt corn planting and shift more area to soybeans," said Ole Houe, director of advisory services at brokerage IKON Commodities.
"This could be a real game changer. It could see corn explode to the upside if we lose more than 2 million acres."
There are forecasts for more rain in the U.S. Midwest after recent flooding, which will keep farmers out of the fields in southern areas that start plant corn in early April.
It has resulted in uncertainty over the scale of corn planting as flooding could push farmers to shift some acreage towards later-planted soybeans.
At least 1 million acres (405,000 hectares) of U.S. farmland were flooded after a "bomb cyclone" storm left parts of nine major grain producing states under water, satellite data analysed by Gro Intelligence for Reuters showed.
Soybean futures received support from optimism about a trade deal with China after the U.S. Agriculture Department said private exporters reported the sale of 828,000 tonnes of soybeans to China.
Commodity funds were net buyers of CBOT corn, soybean, wheat, soymeal and soyoil contracts on Monday, traders said.