Chicago corn futures rose for a second session on Thursday, recovering from one-week lows on expectations of further reductions in estimates for U.S. corn yields.
Wheat edged higher after gaining about half a percent in the previous session, supported by prospects of strong demand for U.S. shipments and lower supplies in Europe.
Chicago Board of Trade's most active soft red winter wheat futures rose 0.25 percent to $4.04 a bushel while corn was up 0.2 percent at $3.32-1/2 a bushel.
Soybeans also rose 0.2 percent to $9.44-3/4 a bushel.
"We see scope for a further downgrade in the USDA's corn yield estimates and continued strength in U.S. corn exports amid a severe shortage of corn outside the United States," said Rajesh Singla, head of agriculture research at Societe Generale.
The U.S. Department of Agriculture trimmed its corn harvest outlook slightly from the previous month, but the crop is still expected to be the largest on record.
The agency on Monday reduced its U.S. corn production forecast to 383.4 million tonnes from the 384.9 million tonnes estimated in August.
Lower wheat output in Europe is preventing further declines in wheat prices. Consultancy Strategie Grains on Thursday cut its estimate of this year's soft wheat production in the European Union, with a sharp reduction in the expected share of milling-quality wheat because of weather damage.
Strategie Grains put EU soft wheat production at 136.5 million tonnes, down 1.4 million tonnes from its previous monthly estimate and now 10 percent below a record 2015 crop.
Europe's largest grain producer France had its the lowest soft wheat harvest in 23 years at 28.5 million tonnes, with crops showing poor quality, farm office FranceAgriMer said on Wednesday, forecasting that exports outside the EU would be only a third of last season's level.
Soybeans remained supported by uncertainty about Argentina's export plans. Argentina's government is considering postponing next year's proposed tax cut on soy exports as Latin America's third-largest economy contends with a revenue-sapping recession.
U.S soybean processors are likely to have slowed crushing during August because of seasonal maintenance to ensure they would be ready to handle the influx of beans from the forthcoming harvest, analysts said.
The National Oilseed Processors Association (NOPA), the largest U.S. trade group for the industry, is expected to report that its members crushed 136.233 million bushels of soybeans in August, based on the average of estimates by six analysts.
(Editing by Joseph Radford and David Goodman)