SHANGHAI, Dec 30 (Reuters) - Chicago corn and soybeans slid from their 6-1/2-year high on Wednesday, as Argentine soy crushers signed a deal with oilseed workers to end a strike that had been pushing up prices in recent days. Corn had been on a winning run for the past 12 days. Wheat prices were also down on Wednesday. * The most-active soybean contract on the Chicago Board of Trade (CBOT) slid 0.6% to $12.88-3/4 a bushel at around 0200 GMT. The market had reached $12.99-1/2 a bushel on Tuesday, its highest since June 2014. * Corn was last down 0.3% at $4.64-3/4 a bushel, also slipping from its multi-year highs gained in its previous session. It rose to $4.67-1/4 a bushel on Tuesday, also its highest since June 2014. * Wheat was down 0.1% at $6.18 a bushel. * Argentina’s CIARA soy crushing chamber said late on Tuesday that it signed a contract with oilseed workers, ending a 20-day wage strike that had paralyzed exports from the world’s top supplier of soymeal livestock feed. * The deal includes a gradual, two-part 25% increase in salaries from January to August, with increases for the rest of the year to be determined by official inflation figures, CIARA said in a statement. * A labour strike by oilseed workers and grain inspectors had earlier idled Argentina’s ports, backing up more than 140 export ships. * European wheat rose on Tuesday, supported by Algeria’s tender believed to be sourced in Europe and a rebound on U.S. markets, traders said. * Commodity funds were net buyers of Chicago Board of Trade corn, wheat, soybean, soymeal and soyoil futures contracts on Tuesday, traders said. * Jordan’s state grain buyer is believed to have made no purchase in an international tender for 120,000 tonnes of animal feed barley which closed on Tuesday, European traders said. A new tender is expected in the coming days to close on Jan. 5, seeking shipment in June and July 2021. * Asian shares retreated on Wednesday as investors cashed in on a recent rally, while the euro flirted with highs not seen in more than 2-1/2 years as hopes of a gradual global economic recovery supported demand for riskier currencies. * The dollar fell to its lowest in more than two years against the euro on Wednesday as currency traders looked past a new delay in U.S. stimulus cheques and maintained bets additional financial aid was still likely. * Oil prices gained more ground on Wednesday as a U.S. coronavirus fiscal aid package and expectations of global economic recovery lifted hopes for higher fuel demand.