However, worries about disruption to grain exports from Russia and Ukraine were tempered by comments by Ukrainian President Volodymyr Zelenskiy, who said on Monday there will be a "diplomatic track" with Russia regarding Black Sea attacks.
A report that a U.S. military aircraft landed in Moscow on Tuesday added to speculation about possible efforts towards de-escalation in Russia's war with Ukraine.
"Today's focus is whether diplomacy can translate into any real improvement in shipping," CM Navigator analysts said in a note.
"Physical wheat markets still look considerably tighter than futures suggest," they added.
There has been growing talk about importers seeking alternatives to Russian and Ukrainian wheat, pushing up physical premiums in the European Union.
News that India was removing restrictions on wheat exports also helped curb futures, as the move suggested an additional source of supply for importers.
CBOT wheat Wv1 was 1.6% lower at $6.88-1/4 a bushel, having hit $7.15 in the previous session, its highest since May 2024.
CBOT soybeans Sv1 were down 0.5% at $12.18 a bushel.
Oil prices fell for a second day as investors viewed new U.S. sanctions against Iran as posing less risk to supplies than military escalation.O/R
Soybeans like corn are widely processed for biofuel and are sensitive to oil fluctuations.