BRUSSELS, NOV. 16 -- Agriculture Secretary Clayton K. Yeutter warned today that the odds are "less than 50-50" that the United States and Western Europe will be able to break their stalemate over farm subsidies and prevent the collapse of global free-trade negotiations.

Calling himself "an optimist by nature," Yeutter said that several days of talks here with the 12-nation European Community had left him "very pessimistic" about the chances of averting a major trade war because of Europe's reluctance to cut back what the United States regards as unacceptable subsidies to its farmers.

"I would assess the probability of success at much less than 50-50 at the moment," Yeutter said at a news conference following a meeting here between U.S. Cabinet members and senior EC officials.

The other American participants -- Secretary of State James A. Baker, chief trade negotiator Carla A. Hills and Commerce Secretary Robert Mossbacher -- joined the Europeans in taking the more upbeat line that redoubled negotiating efforts still can end the deadlock threatening the latest effort to overhaul the General Agreement on Tariffs and Trade, known as GATT.

While their language was couched differently, it did nothing, however, to contradict Yeutter's blunt judgment that the talks are falling hopelessly short of the goal of agreement by year's end. If that happens, U.S. officials and most economists predict a wave of protectionism that would hurt the world economy, and especially the economies of the less-developed nations.

"We need effective, meaningful, disciplined control of agricultural export subsidies so that farmers who don't get subsidies are able to compete with European products both in European markets and world markets," Yeutter said.

Germany and France, the two most powerful members of the EC, have strongly opposed cutting subsidies because of pressure from the politically powerful farm blocs in each country.

The United States, which started out demanding the end of all subsidies during the coming decade, has scaled back its goal to "substantial elimination" of payment to European farmers.

The current European position calls for a 30 percent cut in internal support payments, but it does not offer reductions in export subsidies or promise an end to the trade barriers around the EC common market.

Despite the growing sense of pessimism here, both the Americans and Jacques Delors, president of the EC Commission, the community's executive body, vowed today to try to meet the December deadline for concluding the talks. Yeutter said, "I don't think we should give up. It's too important not to keep trying."