The two leading candidates for governor fulfilled a long tradition of politicking at the Minnesota State Fair, showing up on opening day to ask for votes and take a few swipes at one another.

DFL Gov. Mark Dayton called the Fair "a great Minnesota tradition" -- and an ideal spot for candidates. "You stand in one place and the rest of the state comes passing by," Dayton said.

The governor shook hands, posed for pictures and chatted with supporters for about 45 minutes at the DFL booth. Later in the day he was scheduled to be doused with a bucket of ice water while live on the radio, after accepting the "ice bucket challenge" - a fundraiser for ALS that has been popular and high-profile nationwide in recent days.

Meanwhile, Johnson kicked off the first of what he said would be at least 10 State Fair appearances with a press conference at his campaign booth. He challenged Dayton to 13 debates between now and Election Day, and suggested that two should be held at the Fair.

The Dayton campaign had previously agreed to six debates, and said it would not go beyond that. Johnson said that's not enough. There has been a tradition of political debates at the Fair, and Johnson called it the perfect setting to talk issues.

"You'll not find a broader cross section of Minnesotans than at the State Fair," Johnson said.

But Dayton pointed out that his predecessor, Gov. Tim Pawlenty, participated in seven debates as a candidate in 2002 and six debates as an incumbent in 2006. He said that would be plenty for voters to draw distinctions between himself and Johnson.

"It's a contrived issue. I think he should focus on things people really care about," Dayton said.

The six debates the Dayton campaign agreed to are: Oct. 1 in Rochester, the week of Oct. 6 in Moorhead, Oct. 14 in Duluth, the week of Oct. 20 in Minneapolis or St. Paul, Oct. 31 in St. Paul and Nov. 2 in St. Paul.

Johnson said if six debates are all that Dayton agrees to, then he'll be there as well.

Johnson said he'd be at the Fair on at least 10 of its 12 days, sometimes for multiple visits. Dayton, too said he'd make multiple visits to the Fair. He has plans to be back Friday for several Fair events.