CBOT July soft red winter wheat was last down 22-1/4 cents at $6.58-1/2 per bushel; K.C. July hard red winter wheat was last off 23-1/2 cents at $6.14-1/2 per bushel, and MGEX July spring wheat lost 34 cents to $7.30-3/4 per bushel.
Russian agriculture consultancy Sovecon said on Friday that it had raised its forecast for Russia's 2021 wheat crop by 1.5 million tonnes to 82.4 million tonnes.
CBOT July corn was last down 8-1/4 cents to $6.90-3/4 per bushel, while new-crop December corn eased 12-1/4 cents to $6.04-1/4.
Commercial participants lowered their net short position to 110,351 contracts from 116,691 a week earlier.
In Euronext's rapeseed futures and options, non-commercial market participants increased their net short position to 12,119 contracts from 10,594 a week earlier.
MGEX spring wheat leading CBOT soft red winter wheat and K.C. hard red winter wheat contracts higher, with dry conditions in northern US Plains fueling the gains.
Russia competes with the European Union (EU) for the rank of the world's largest wheat exporter. Egypt, Turkey and Bangladesh are the largest buyers of its wheat.
Russian exports will decline because of a smaller wheat crop, which Sovecon expects to reach 80.9 million tonnes, down from 85.9 million tonnes in 2020, it said in a note.
That was down from 31.27 million tonnes cleared by the same week last season, the data showed.
Since Jan. 1, the European Commission's data has covered the EU's 27 countries only, whereas previous figures up to Dec. 31 covered both the EU-27 and Britain.
Wheat futures rising on bargain buying after most-active contract fell 2.3% on Monday, its biggest daily percentage drop since March 30. Strength in corn market underpins wheat.
The US Agriculture Department said that the US winter wheat crop was rated 48% good to excellent as of May 2, down 1 percentage point from a week ago.