Winners of key races in Tuesday's primary elections will face not only candidates from the opposing party in November election, but formidable independent opponents as well.

Attorney General Joseph E. Brennan won the Democratic nomination for governor, and will face Linwood E. Palmer Jr., the Republican winner.

But also on the ballot will be the Rev. Herman C. (Buddy) Frankland, an ultraconservative Baptist minister from Bangor who said he will follow in the "ideological footsteps of Gov. James B. Longley."

Longley, the nation's only independent governor, is keeping a campaign promise not to seek a second four-year term.

Frankland filed petitions with more than 2,000 signatures Tuesday to get into the gubernatorial race.

Many political professionals here claim that he has an outside chance of repeating Longley's upset victory. Frankland's entry also could siphon votes from Palmer the GOP candidate, because of his appeal to conservatives who otherwise would vote Republican.

For the past 11 years, Frankland has been a minister of a church in Bangor that is described as the largest Baptist congregation north of Boston. The church operates two dozen 66-passenger buses to transport people to Sunday services.

Frankland said he will start raising a $250,000 campaign warchest and will spend 18 hours a day campaigning. He said he will emphasize two promises: Texas will not ge raised and government will be returned to local control.

In the hotly contested Senate race between incumbent William D. Hathaway (D) and Rep. William S. Cohen (R), three independents have filed petitions to get their names on the November ballot, but only one is thought to be a vote-getter.

He is Hayes E. Gahagan, 30, a former state representative and senator from Caribou who renounced his GOP enrollment, saying: "The Republican Party left me, I didn't leave them."

Gahagan took a two-poge $2,300 advertisement in last week's Maine Sunday Telegram, the only statewide Sunday newspaper, to announce his candidacy and outline his political philosophy.

A founder of the Constitutional Political Alliance, a lobby group whose purpose is to "infuse into political arena Christian principles, ideas and ideals," Gahagan has started soliciting funds and aides say he has "a pretty good kitty" to get the campaign under way.

His candidacy is expected to cut into the Cohen's vote.