Michael Dukakis picked fellow governor Bill Clinton of Arkansas Saturday to nominate him for president at the national convention, as speculation over vice presidential candidates continues to be the hottest topic for both parties.

Dukakis and Republican George Bush, their parties' presidential nominations sewn up, aren't tipping their hands over running mates.Dukakis met Saturday with Reps. William Gray III of Pennsylvania and David R. Obey of Wisconsin and prepared to host Jesse Jackson on July 4. Gray is chairman of the House Budget Committee; Obey sits on the House Appropriations Committee and the Joint Committee on Economics.

Bush, meanwhile, was spending a quiet few days at a vacation home in Kennebunkport, Maine, before heading back to the campaign trail for a Fourth of July swing through Michigan, Illinois and Missouri.

What activity there was on the GOP side was provided by Sen. Bob Dole, who fenced with reporters in California over his vice presidential chances.

"I'd be happy to discuss it" with the Bush campaign, Dole said. "If someone makes that call . . . you talk about it very seriously."

The Kansas Republican met with reporters following a private breakfast in Sacramento with Gov. George Deukmejian of California, another possible Bush running mate.

Clinton is the second southerner named to a prominent Democratic convention speaking role. Texas State Treasurer Ann Richards was named last week to deliver the keynote speech opening the convention in Atlanta July 18.

Clinton will address the delegates the next night, formally nominating Dukakis for president. He will deliver a 15-minute speech focusing on Dukakis' record as Massachusetts governor and his leadership abilities, the Dukakis campaign said.

Tradition at recent conventions is for a brief nominating speech followed by one or two seconding speeches. But Dukakis spokesman Mark Gearan said Clinton would deliver the sole nominating address.

Clinton, who has worked at length with Dukakis as part of the National Governors Association, told a news conference in Little Rock that Dukakis is sincere about wanting to spur economic development in the South.

Jackson, who is expected to have his name placed into nomination as well, was to visit Dukakis Monday. Jackson and his wife, Jackie, are to dine with Dukakis and his wife, Kitty, then attend the Boston Pops Independence Day concert on the banks of the Charles River.

Dukakis aides say the meeting is largely social but that they expect the subject of the No. 2 spot on the ticket to come up.

Sens. John Glenn of Ohio and Lloyd Bentsen of Texas are considered the Democrats' leading candidates, followed by Rep. Lee Hamilton of Indiana and Sen. Bob Graham of Florida.

Dukakis, who campaigned in Ohio Friday with Glenn, said he would "make a decision when I'm ready to make a decision."

Glenn received an enthusiastic welcome from a home-state crowd at an Auto Workers union hall in Dayton.

"I've been taking a poll all over America about running mates," said Dukakis. "What do you think about John Glenn?" The crowded cheered and whistled.

"Sounds unanimous to me," said the Massachusetts governor.