SINGAPORE/PARIS: Chicago corn and soybean futures rose on Monday as a forecast of lower US production by a widely watched crop tour underpinned prices, while wheat extended last week's 7% jump on further concern about weather threats to crops in Argentina.

"US storm damage and Chinese demand are supporting corn prices," said Phin Ziebell, an agribusiness economist at National Australia Bank in Melbourne. "But we have lower demand for ethanol which will limit the upside potential."

The most-active corn contract on the Chicago Board Of Trade rose 0.6% to $3.42-1/2 a bushel by 0948 GMT.

Soybeans gained 0.4% to $9.08-1/2 a bushel and wheat rose 0.2% to $5.36-1/4 a bushel.

Advisory service Pro Farmer projected US corn and soybean harvests will be below the US Department of Agriculture's (USDA) forecasts, with a corn crop of 14.820 billion bushels based on an average yield of 177.5 bushels per acre and a soybean crop of 4.362 billion bushels based on an average yield of 52.5 bushels per acre.

Tropical storms in the US Gulf offered hope for much-needed rain in parts of the Midwest, a major growing region for corn and soybeans.

"Export activity to China is a clear element of support for corn and soybeans, but the volumes contracted remain well below the mid-January trade agreement," French consultancy Agritel said in a report.

Wheat continued to be supported by reports that harsh frosts in Argentina, a major global export competitor, had combined with severe dryness hurting recently planted crops.