Canadian Foreign Minister Joe Clark said today he discussed the possibility of Canada's participation in President Reagan's "Star Wars" program during his meeting this week with Soviet Foreign Minister Andrei Gromyko.

Clark, the first Canadian foreign minister to pay an official visit to the Soviet Union in more than a decade, said Canada is considering a U.S. invitation to join in a NATO technological partnership for research in the Strategic Defense Initiative program.

He said at a press conference that in his meetings with Gromyko and other Soviet officials he had stressed areas of potential cooperation between the two countries. But he said that he also "strongly affirmed" Canada's support of U.S. positions at the arms negotiations in Geneva, in particular for continuing research in space-based defense.

Clark said Canada had not reached a decision on the invitation, offered to NATO allies last week by U.S. Defense Secretary Caspar W. Weinberger, to join in a technological exchange on space-based defense.

In an article today, the Communist Party daily Pravda warned West Germany against participating in the program. Stopping the program has become the Soviets' top priority at the Geneva negotiations. Noting Bonn's expressed desire to strengthen its ties with Eastern Europe, Pravda said those ties "will be largely determined by West German policy on matters concerning [the Soviet Bloc's] security interests."

Clark said that in his conversation here he made a point of underlining the "serious disagreements" between Canada and the Soviet Union.

"But," he said, "I did not dwell unduly upon them but tried to turn more active attention to areas" where cooperation is possible.

Although Clark's visit here was primarily political, he said economic ties were discussed. Negotiations to renew Canada's grain agreement with the Soviet Union, which expires in 1986, will begin later this year, a Canadian spokesman said.