DULUTH, Minn. — House Speaker Margaret Anderson Kelliher outlasted a slew of rivals Saturday to emerge as the Democratic-Farmer-Labor Party’s choice for governor.

Kelliher wrapped up the endorsement after a daylong floor battle that ran to six ballots and did not end until Minneapolis Mayor R.T. Rybak conceded shortly after 11 p.m.

Kelliher becomes the first woman backed by a major-party for the state’s highest elected office. No woman has been governor of Minnesota, and Democrats haven’t held the office since 1990.

“Are you ready to make some history? Are you ready to make history together?” Kelliher asked the convention as she accepted the endorsement.

Kelliher’s path to November is far from clear, with three major Democrats — former U.S. Sen. Mark Dayton, Ramsey County Attorney Susan Gaertner and former state Rep. Matt Entenza — committed to run in the primary.

In his concession, Rybak called for all three to step aside for Kelliher.

“The stakes right now are too great for us to delay and divide any longer,” he said.

About 1,350 DFL activists convened at the Duluth Entertainment and Convention Center to make their endorsement.

Kelliher got nearly 47 percent on the fifth vote by convention delegates, still shy of the 60 percent threshold needed for her party’s backing. The results of the sixth ballot weren’t released before Rybak dropped from the race.

She earned dramatic gains after state Rep. Tom Rukavina, an Iron Range legislator with strong labor backing, dropped out and threw his support to her. Another rival, state Sen. John Marty, the party’s 1994 gubernatorial nominee, also urged his fans to fall behind her.

“There are a lot of people who are interested in making sure the DFL-endorsed candidate wins in August,” Kelliher told reporters after her speech.

She added: “We need to end the 24-year drought of not having the governor’s office.”

State Rep. Paul Thissen of Minneapolis dropped out in third place without backing Kelliher or Rybak.

Democrats have been shut out of the governor’s office since 1990. It’s been four decades since they backed a winner for an open seat.

The governor’s race is open this year because two-term Republican Gov. Tim Pawlenty is moving on. The GOP will pick between Reps. Tom Emmer and Marty Seifert next week in Minneapolis.

Dayton and Gaertner skipped the party endorsement contest. Entenza withdrew after addressing the delegates and saying he will go on. He plans to begin his primary campaign Sunday at the state Capitol in St. Paul and start running television ads next week.

On Saturday evening, Thissen, Rybak and Kelliher each appeared before a group called ReNew Minnesota, whose members went into the convention split among the three candidates. The group tried to consolidate behind one of them, but none of the three got the required three-fifths vote. Rybak came closest.

Kelliher emphasized the importance of putting a Democrat in the governor’s office.

Some of Kelliher’s supporters said it would be groundbreaking for the DFL to back a woman for governor. No woman has ever held Minnesota’s highest elected position, and it was an emotional moment when Kelliher prevailed.

“I’m thrilled,” said Jackie Stevenson, a longtime DFL activist from Minnetonka. “The tears are coming. I’ve waited so long.”

Minnesota Republicans greeted the endorsement with a statement questioning Kelliher’s appeal beyond Minneapolis and St. Paul, predicting she would “fall flat in the suburbs and Greater Minnesota.”

Deputy GOP Chairman Michael Brodkorb said his party has a jump start on Democrats, with no serious GOP primary contest anticipated.

“A hundred days before they have their final candidate we’re going to have a Republican candidate who’s going to have an opportunity to have a one-on-one discussion with Minnesota about their record. I think our chances are great,” he said.