Taciturn sheep farmer Thorbjorn Falldin, leader of the anti-nuclear Center Party, became prime minister of Sweden last week by virtue of his ruling coalition's single-seat majority in parliament

He promised then that he and his three-party government, in which the Liberals and Conservatives share power, will abide by the decision of swedish voters in a March referendum on the future of nuclear power.

"We are agreed that the referendum shall provide the verdict on this question," Falldin told parliament in a preview of his government's policies. The referendum is expected to offer voters the choice of keeping Sweden's six operating nuclear reactors in service until 1990 or doubling the program with six more reactors, four of which already have been built.

Despite his party's strong opposition to nuclear power, Falldin said he would continue as prime minister is the Swedes voted to put the additional reactors into operation. He resigned as prime minister of an earlier coalition government a year ago after a disagreement with his Cabinet partners about nuclear energy.

Falldin also told parliament that he would propose ways to cut the amount of income tax the Swedes pay. But he said he would seek increases in oil, gasoline and electricity taxes, both to make up the lost revenues and to promote energy savings. Sharp increases in oil prices have hurt the Swedish economy and supply shortfalls have threatened a shortage in home heating oil this winter.

The Cabinet contains eight Conservatives, headed by Conservative leader Gosta Bohman, who became economics minister. The Conservatives made the biggest gains in last month's national election in Sweden on the strength of Bohman's energetic campaign for tax cuts.

Seven Cabinet posts went to Falldin's Center Party and five to the Liberal Party. The Liberals' leader, former prime minister Ola Ulsten, became foreign minister. The Cabinet contains five women, the most of any government in Europe.

As expected, Olof Palme's opposition Social Democrats, who ruled Sweden for 44 years before being ousted in the election of 1976, failed by one vote in parliament from blocking formation of Falldin's government. The Social Democrats plan to harness the fragile and sometimes quarrelsome coalition in an effort to force new elections after the March nuclear referendum.