The Democratic National Committee adopted its 1988 presidential nomination rules in a harmonious session here yesterday, though not without a brief skirmish over minority rights and a reminder of how tenuous is its control over the pace of presidential politics.

The one floor fight -- a far cry from the angry rhetoric and occasional walkouts of past rules-making sessions -- arose over an amendment by former Atlanta mayor Maynard Jackson to eliminate the threshold of primary or caucus votes a candidate must reach in order to be awarded delegates.

Jackson called the 15 percent threshold (lowered from 1984's 20 percent) "unnecessary and unfair," and said it worked a particular hardship on black candidates because they do not have as big a "marketplace" of voters to draw from.

Susan Estrich of Massachusetts, co-chairing the party's Fairness Commission that drafted the rules, said the threshold was essential to the process of nomination by consensus.

Jackson's amendment to do away with the threshold was beaten on a voice vote and his subsequent amendment to reduce it to 10 percent was defeated, 178 to 92.

Afterward, he said "this will not divide us," and announced his support of the full Fairness Commission report, which passed by voice vote. The new rules make only minor changes from those used in 1984.

The relative absence of rancor over the threshold may stem from the fact that the Rev. Jesse L. Jackson, whom Maynard Jackson supported in 1984 and who has complained about thresholds, might benefit from the 15 percent threshold if he runs again in 1988.

Jackson won roughly 19 percent of the votes nationwide in the 1984 primaries and caucuses. If he retains this base in 1988, he will top the threshold in many states while others in a multicandidate race will not. The second- or third-place finisher may "inherit" their delegates.

In addition to adopting its rules, the DNC passed a resolution asking state parties not to "sponsor, condone, support or lend credence" to presidential straw polls of the kind that proliferated in 1983.

But even as DNC Chairman Paul G. Kirk Jr. urged passage, he noted with chagrin that a straw poll for 1988 was under way in the back of the room, where ballots were being distributed by a CBS-TV crew. He advised the DNC's 378 members -- who all will be unpledged delegates to the 1988 convention -- not to fill them out.

The straw poll resolution is a response to concern that the movement to hold southern states' primaries or caucuses at the beginning of the 1988 nomination season will advance the unofficial winnowing process into 1987.

"The danger is that it will all be over in a 'poof' in March," said Iowa state chairman Arthur Davis. "And I'm sure, in response, all the players involved in the process, including the press, will figure out a way to have it begin earlier and earlier."

But not yesterday. After collecting about 100 ballots, the CBS crew, expressing concern that it did not have enough ballots and that more than one appeared to be filled out in the same hand, decided not to broadcast the result.