Corn edged higher, rebounding from a near three-week low, while soybean prices also rose slightly after Tuesday's slide in a broad retreat on international oilseed markets.
Wheat markets have been fired up in the past week by deteriorating conditions for US spring wheat in the parched northern Plains and concerns over the impact of a heatwave in top European Union producer France.
However, the prospect of another large harvest in Russia and Ukraine this year was underlining a backdrop of ample global supplies.
"The reality is we will need to see widespread production losses to change the fundamentally bearish supply picture (for prices)," said Phin Ziebell, agribusiness economist at National Australia Bank.
The most active wheat futures on the Chicago Board of Trade were down 1.3 percent at $4.71 a bushel at the end of the overnight session. On Tuesday prices hit their highest since June 23 last year at $4.75-3/4 a bushel.
Minneapolis Grain Exchange (MGEX) spring futures also eased, with spot prices down 1.3 percent at $6.48 after setting a 2-1/2 year high at $6.60 earlier in the session.
In Europe, December milling wheat on the Paris-based Euronext market slipped by 0.7 percent to 178.75 euros, having closed lower on Tuesday in a pullback from an 11-month high of 183 euros earlier in the day.
Traders were digesting weather projections for some rain in the northern US and in western Europe next week.
Rain and cooler temperatures in northwest Europe next week were expected to help corn but come too late for wheat after yield losses this week, Commodity Weather Group said.
The most active corn futures rose 0.4 percent to $3.71-1/2 a bushel, recovering from the previous session's fall to their lowest since June 1 at $3.69-1/4 a bushel.
The most active soybean futures inched up by 0.1 percent to $9.28-3/4 a bushel.