Soybeans eased after closing higher on Monday on expectations of a rebound in Chinese demand, while corn was little changed, holding on to last session's 1.6 percent climb amid tight supplies.

The US Agriculture Department said its rating of the winter wheat crop fell to 34 percent good-to-excellent, below analysts' expectations, due to persistent dry conditions in the US Plains.

The ratings were a record low for November and raised questions about how healthy the crop will be when it emerges from dormancy in the spring.

"There is positive tone in the wheat market (on prices) as US crop ratings have dropped to a record low and we have lower production in Australia," said Lynette Tan, an analyst at Phillip Futures in Singapore.

"Agricultural markets were supported by optimism in the financial markets yesterday but a firm dollar is weighing on commodities."

The dollar index, which measures the strength of the greenback against a basket of currencies rose 0.1 percent on Tuesday, adding to pressure on commodity markets.

The wheat harvest in Australia, the world's second largest exporter, is in full swing with framers reporting lower protein scales and poor yields.

The harvest in New South Wales and Queensland, the states that produce top quality hard wheat, contains less protein than usual, traders and farmers said, compounding expectations for lower national output.

The market expects to see an improvement in demand for US wheat as supplies tighten in Australia and Ukraine.

Chicago Board of Trade's December wheat had added 0.3 percent to $8.44-1/2 a bushel by 0225 GMT. January soybeans fell 0.1 percent to $13.93 a bushel, while December corn gained a quarter of a cent to $7.39 a bushel.