4/14/2021 SINGAPORE, April 15 (Reuters) - Chicago corn futures gained more ground on Thursday to trade near the previous session's eight-year top, as concerns over cold weather damage to the crop across the U.S. grain belt underpinned prices. Wheat edged lower after Wednesday's rally which lifted the market to its highest in more than a month, while soybeans extended gains. FUNDAMENTALS * The most-active corn contract on the Chicago Board of Trade (CBOT) rose 0.4% to $5.96-1/4 a bushel, as of 0026 GMT, not far from the previous session's highest since June 2013 at $5.98 a bushel. * Soybeans added 0.3% to $14.14-1/4 a bushel, while wheat lost 0.1% to $6.47-1/4 a bushel, after climbing to