Grains caught between lower dollar and flush supplies in South America CHICAGO, March 22 (UPI) -- Grain futures prices were mixed on the Chicago Board of Trade Thursday dollar index off 0.59 percent to 82.38 on the International Exchange. Corn was off 1 1/2 to off 8 3/4; soybeans were off 7 1/2 to off 11 1/4; wheat was up 1 to up 2 1/4 and oats were up 1 1/4 to up 5. Corn trading was choppy, with futures closing modestly lower. Wheat futures rose with help from a lower dollar. Soybean prices dropped with pressure from flush supplies in South America. Corn: May 7.26 1/4 off 6 3/4, Jly 7.08 1/2 off 8 3/4, Sep 5.96 3/4 off 1 1/2, Dec 5.65 1/4 off 3 1/4. Soybeans: May 14.40 1/2 off 8 1/2, Jly 14.18 off 7 1/2, Aug 13.73 off 8 1/4, Sep 13.01 1/4 off 11 1/4. Wheat: May 7.29 3/4 up 1, Jly 7.29 1/4 up 1 3/4, Sep 7.34 3/4 up 2 1/4, Dec. 7.46 1/4 up 2. Oats: May 3.96 1/4 up 1 1/4, Jly 3.90 1/2 up 2 3/4, Sep 3.67 1/4 up 2 3/4, Dec 3.62 1/2 up 5.