Chicago corn futures rose for a seventh consecutive session on Tuesday, with the market touching a nearly eight-year high as adverse weather in Brazil and the United States raised concerns over global supplies.
Wheat climbed to its highest since February 2013, while soybeans hit a near eight-year peak.
"The market remains worried about Brazil's second corn crop being irredeemably out of synch with seasons," said Tobin Gorey, director of agricultural strategy at Commonwealth Bank of Australia. "And cool weather in the U.S. is making people think, if not quite worry, about planting delays."
The most-active corn contract on the Chicago Board of Trade (CBOT) added 0.1% at $6.58-1/4 a bushel by 0159 GMT, near the session's peak of $6.66 a bushel, its highest since June 2013.
Soybeans fell 0.4% to $15.35 a bushel, after hitting a June 2013 high earlier in the session at $15.45 a bushel. Wheat rose 0.3% to $7.42-1/2 a bushel, not far from its highest since February 2013 at $7.47 a bushel hit earlier in the day.
The U.S. Department of Agriculture (USDA) said the country's farmers were able to plant 17% of their intended corn acres as of Sunday, in line with the average estimate in a Reuters poll of analysts. ]
But corn planting is still lagging behind the five-year average pace of 20%.
Soybean planting was 8% complete by Sunday, the USDA said, matching the average analyst estimate and ahead of the five-year average of 5%.
Potential yields of this year's winter grain crops in the European Union have declined slightly since March as cold and dry weather hampered development and also delayed sowing of spring varieties, the EU's crop monitoring service said.
Russian wheat export prices rose for a third week in a row last week, buoyed by higher prices in Chicago and Paris on supply concerns, analysts said on Monday.
Commodity funds were net buyers of CBOT corn, wheat, soybean, soyoil and soymeal futures contracts on Monday, traders said.