U.S. grains tumbled on Tuesday, with wheat falling about 2 percent, under pressure from a stronger dollar and a broad-based fall in commodity markets linked to renewed economic concerns. 
Corn and soybean prices also fell although tight suppliesand concerns about drought-damaged South American crops helped to limit losses. 
Grains are "taking it on the chin today", said Shawn McCambridge, analyst at Jefferies Bache in Chicago. "When you have the outside markets as weak as they are, that contributes to the long-term uncertainty in this market." 
Equities tumbled on worries that Greece will be unable to complete a major debt restructuring deal and on growing concern that global economic growth is weakening, and investors' fears
spilled over to commodities.  
The dollar shot up 0.6 percent, making goods priced in the U.S. currency less competitive in world trade, while crude oil lost more than 1 percent. 
Grains came into Tuesday's session overbought, McCambridge said, after last week's big gains. 
CBOT May corn dipped 7 cents or 1.1 percent at $6.53-3/4 a bushel, pressured by outside markets and profit-taking after the rise on Monday to a four-month high. 
Traders were digesting word from China that it will not need to import large amounts of corn this year as it has enough reserves, but traders said the world's second-largest consumer  
was likely talking down prices ahead of a shopping spree.

Source: Reuters