BOSTON - The relatively quiet campaign to fill the late Edward M. Kennedy's Senate seat was matched by equally light turnout yesterday as voters picked two state politicians to face off in next month's general election.

Attorney General Martha Coakley, 56, won a four-way race for the Democratic nomination, while State Sen. Scott Brown, 50, bested a perennial candidate to win the Republican nomination.

Coakley's win was her first step toward becoming the first female senator from Massachusetts, a state otherwise known for its liberal political tradition.

Brown, who has carved out a decidedly conservative record, faces an uphill challenge in a state where the majority of voters are independents but frequently vote Democratic.

Election officials said turnout in Boston - a city bearing the Kennedy family image and name throughout - was a meager 10 percent, with similar turnout in most other cities.

Brown is a veteran legislator and lieutenant colonel in the Army National Guard who has also gained local notoriety as a former Cosmopolitan centerfold model and the father of an American Idol contestant. He earned 78 percent of the vote, with 1,543 of 2,168 precincts reporting.

Coakley earned 47 percent of the vote, ahead of U.S. Rep. Michael Capuano with 28 percent; Alan Khazei, cofounder of the City Year service organization with 13 percent; and Boston Celtics co-owner Stephen Pagliuca with 12 percent.

Kennedy's widow, Vicki, called each of the Democrats early yesterday to wish them well, an aide said. His family had been careful not to endorse any one candidate.

Kennedy, who died Aug. 25 of brain cancer, held his seat for nearly 47 years.

His seat has been held on an interim basis by Paul G. Kirk Jr., a former Democratic National Committee chairman, until it is filled permanently Jan. 19.