MARKET DISCOUNTS HIGHER SOVIET GRAIN IMPORTS Grain analysts said the increase of three mln tonnes in 1986/87 Soviet grain imports is unlikely to affect the market Tuesday. They said the market already has discounted higher Soviet imports, partly on news last month that the Soviet Union bought one mln tonnes of U.S. corn, and on rumors that the Reagan administration is pushing for authority to sell the Soviets U.S. wheat under the Export Enhancement Program. In its supply-demand report, the USDA raised its estimate for 1986/87 Soviet grain imports to 26 mln tonnes from 23 mln. "That was business already done, for all practical purposes," said Drexel Burnham analyst Dale Gustafson, reflecting similar statements made by other analysts.