US FOB Gulf soyabean basis offers jumped on Monday amid tight supplies and talk of China in the market, while corn was slightly higher and wheat was steady, traders said.
Delays in exporting soyabeans and slow farmer sales in Brazil are allowing US soyabeans to be competitive against South American supplies, traders said.
China, the world's top soya importer, has switched up to six cargoes to the United States from Brazil, traders said.
"China is looking for beans and now that it feels real, nobody wants to show aggressive numbers," said a trader of why soyabean export premiums jumped 4 to 6 cents per bushel.
Corn export premiums at the Gulf climbed 1 to 3 cents per bushel for nearby shipment, reflecting a slowdown in country movement amid a drop in corn futures on Monday.
Corn exports remain routine with traders saying the break in cash prices has not yet sparked fresh export demand.
Taiwan's Members Feed Industry Group will tender on Tuesday for up to 60,000 tonnes of US corn for April/May shipment.
Other importers in South Korea and Taiwan are likely to also seek US corn ahead of China suspending corn exports, said traders in Taipei.
Hard and soft red winter wheat offers were unchanged in a quiet market.
The United States lost to rivals Canada and Australia in Iraq's tender for 1 million tonnes of wheat due to high US prices.
The Iraqi Grain Board announced it bought 500,000 tonnes of Canadian No 2 hard red spring wheat at $188 per tonne FOB and 150,000 tonnes of US hard red winter wheat at $190 per tonne FOB, said US traders.
Traders believe that Louis Dreyfus Corp sold Iraq the 150,000 tonnes of US wheat.
Iraq is also expected to buy 350,000 tonnes of wheat from private Australian firms that will source supplies from monopoly exporter AWB Ltd.
Iraq's trade minister also indicated Baghdad might buy another 500,000 tonnes from Canada and Australia in the near future. Taiwan's Flour Mills Association will tender on Tuesday for about 80,000 tonnes of US wheat, mostly dark northern spring, for April/May shipment.