Virginia Gov. Charles S. Robb surrendered today any role in the selection of a Democratic candidate for the U.S. Senate following a bitter party struggle that many Democrats charge was partly his fault.

Robb, who has come under sharp criticism for his role in the closed-door selection of fallen candidate Owen B. Pickett, said he now does not plan "to endorse or actively support" any candidates prior to the party's nominating convention in Roanoke June 4-5.

The governor's abdication leaves the party without clear leadership as it sets about repairing the damage wrought by a series of emotionally charged incidents -- capped by the sudden collapse Tuesday of Pickett's campaign and by the withdrawal the next day of the threat of an independent candidacy by state Sen. L. Douglas Wilder.

The early favorite of most Democratic Party regulars appeared to be Lt. Gov. Richard J. Davis, a white-haired millionaire mortgage banker who was the Democrats' top vote getter in last November's sweep of statewide offices. The chief question at the moment, however, is whether Davis will actively compete in what is expected to be a wide-open contest for a majority of the 3,624 delegates to the Roanoke convention.

"He's available if the party needs him," said Davis staffer Robert Watson. "We will not be going to Roanoke with a trailer and walkie-talkies."

Contacted in Chicago tonight, where he is attending a bankers' convention, Davis said he had not yet been able to assess his political chances. "I need to talk to a lot of people to inquire if I would be the best nominee," said Davis, "and that can't be handled long distance." Davis tonight would not rule out entering a contested race for the nomination.

Skeptics wonder whether Davis can realistically run for the Senate less than seven months after campaigning for the lieutenant governor's job. They also say his liberal image -- epitomized by his tie- breaking vote in the state Senate against credit card membership fees--could hurt him among business groups and conservatives.

The other contenders for the right to oppose Rep. Paul S. Trible, the expected Republican nominee, include:

* Senate Majority Leader Hunter B. Andrews. First elected to the state Senate in 1964, Andrews is known for his brilliant legislative wizardry, his powerful oratory and a caustic, patrician style. Although many colleagues say he is the best qualified in the field, they acknowledge that his sometimes arrogant and abrasive style could be a drawback for a statewide race.

* Fairfax County prosecutor Robert F. Horan. The 49-year-old Horan, known for his strong belief in law-and-order, was first appointed commonwealth's attorney in 1967. Although popular in Northern Virginia, detractors say he is little known in the rest of state and could have difficulty selling some of his conservative positions to liberals and blacks.

* Former state attorney general Andrew P. Miller of Alexandria. Miller, 49, is credited with having turned the attorney general's office -- which he held from 1970 to 1977 -- into a formidable arm of state government. But there appears to be little support for Miller among party leaders, many of whom were bitterly disappointed by his last two unsuccessful statewide races. Furthermore, Wilder, the state's top black elected officeholder, already has pronounced Miller unacceptable.

According to key advisers, Horan and Andrews are expected to announce their candidacies within the next few days. "We're doing what we can to run," said William Wiley, an Andrews strategist. "He's already talking to party leaders and he's getting pretty good feedback."

Robb's earlier participation in the backroom process that gave Pickett the advantage prompted many Democratic leaders today to question the governor's leadership. Robb entered the selection process last winter at the invitation of four top Democratic contenders in hopes of avoiding a costly and divisive battle for the nomination.

To point the way to a concensus, Robb enlisted the aid of his former campaign manager David Doak who concluded after an informal survey that Pickett, then the state party chairman and state legislator from Virginia Beach, was the most acceptable among party leaders and constituent groups.

Now critics charge that the process -- flawed by secrecy, a lack of open debate and the hint of the Byrd organization's 'anointment and appointment' style -- has strained the tenuous coalition of liberals, conservatives, blacks and independents, that put Robb in office.

"In the short term, he's clearly been damaged," said state Sen. Dudley Emick (D-Botentourt.) "Right now, he's got people mad at him from every aspect of the party. The perception of him as somebody who could keep the coalition together and get his way with the party has suffered."

Like many of his colleagues, Emick predicted that the damage will be short-lived and the party will emerge triumphant in an election year that nationally augurs well for Democrats.

In an effort to unify the party, Robb this week pressured Pickett to drop out of the race as the best way to mollify Wilder. The game plan succeeded in getting both men out of the race, but conservatives were outraged that the governor had moved to support the liberal wing of the coalition. W. Roy Smith, a key conservative fund-raiser, this week warned Democrats against caving in to black demands.

"Some people are very unhappy," said Sen. Joseph Gartlan (D-Fairfax), "The question is how many people are going to pick up their marbles and go home."

In his terse four-paragraph statement today, phoned in to his office from the Sleepy Hole Golf Course in Portsmouth where he was spending the afternoon at the United Virginia Bank Golf Classic, Robb forswore any return to the meetings that selected Pickett.

"In light of all that has taken place, I believe the truly open convention is clearly in the best interest of the Democratic Party," he said.

"Not only will it encourage greater and more enthusiastic participation from all elements of our party, it can also help us generate the critical momentum we'll need to have coming out of the convention in order to make up some of the ground lost prior to the nomination."