CHICAGO, May 21 (UPI) -- Grain futures prices were mostly lower at midmorning Friday on the Chicago Board of Trade. Corn was fractionally lower as concerns about more rain in the Midwest helped limit losses. Soybeans and wheat opened lower on slow exports and good growing weather. Losses in soy oil and meal and declining weekly NOPA crush figures added pressure for soybeans. The midmorning prices: Corn: Jul 2.19 off 1/4; Sep 2.24 1/4 off 1/4; Dec 2.33 unch; May 2.41 3/4 off 1/4. Soybeans: Jul 4.65 off 3; Aug 4.68 1/2 off 2 3/4; Sep 4.70 1/4 off 2 3/4; Nov 4.77 3/4 off 3. Wheat: Jul 2.54 3/4 off 1 1/2; Sep 2.65 off 1 1/2; Dec 2.80 off 2 1/4; Mar 2. 90 1/2 off 2 3/4. Oats: Jul 1.20 1/2 off 3/4; Sep 1.18 3/4 off 3/4; Dec 1.21 off 1 1/4; Mar 1.27 unt.  