CHICAGO: Chicago corn and soyabeans futures climbed on Wednesday as news of Chinese purchases offset strong yield prospects after recent rain across the Midwest offered relief to pollinating corn crops.

Both commodities gained even after the United States ordered China to close a consulate in Houston, escalating diplomatic tensions and putting future purchases in doubt.

Wheat also gained for a second consecutive session after technical corrections from a nearly three month high last week.

The Chicago Board of Trade December corn contract rose 3-3/4 cents to $3.34-1/2 a bushel as of 12:00 p.m. (1700 GMT).

Soyabeans added 2-1/4 cents to $8.98-3/4 a bushel after rising to a high of $9.01-1/4 in earlier trade, while wheat gained 7-1/2 cents to $5.35-1/4 a bushel.

"It all comes down to how much China buys from us," said Dan Smith, commodity broker with Top Third Ag Marketing, "and how we finish off the crop year."

Private exporters reported the sale of 453,000 tonnes of soyabeans to China and 211,300 tonnes to unknown destinations, the US Agriculture Department said. Additionally, there were export sales of 262,000 tonnes to China received in the reporting period, USDA said.

Exporters also sold 207,880 metric tonnes of corn to unknown destinations.

"With the new ripple in the relationship with China, we wonder if some of these purchases ultimately might be cancelled," said Ted Seifried, chief ag market strategist at Zaner Group.

Wheat added for a second day, as technical selling pulled the market off of its highest level since April 23.

"We were due for a correction," said Seifried. "We want to go back and test those highs."