CHICAGO (AP) _ Grain futures were higher in early trading Tuesday on the Chicago Board of Trade. Sept. corn rose by 0.75 cent at $5.13 a bushel. Sept. wheat gained 11.5 cents at $7.28 a bushel. Sept. oats gained 12.5 cents at $3.56 a bushel. Sept. soybeans was up 4.25 cents at $12.98 a bushel....