Virginia state Del. Owen B. Pickett, the obscure state legislator who had been anointed by Gov. Charles S. Robb and other top Democrats to be the party's U.S. Senate candidate this year, today bowed out of the race after concluding he couldn't win the election.

The abrupt withdrawal was immediately viewed as a triumph for Sen. L. Douglas Wilder, the black Democratic state senator from Richmond who had been threatening an independent campaign for the seat of retiring Sen. Harry F. Byrd Jr., in part because of his dissatisfaction with Pickett's commitment to black issues.

As a result of Pickett's withdrawal, Wilder is expected to announce tomorrow that he will abandon plans to run as an independent, Democratic Party sources said.

At a grim 40-minute meeting in the Governor's Mansion Monday afternoon, Robb informed Pickett that if he didn't get out immediately, Wilder would almost certainly announce his candidacy, causing a Democratic blood bath that would sink the party's chances this fall against Rep. Paul S. Trible of Newport News, the expected Republican nominee, according to several individuals at the meeting. Pickett, who has been reassessing his faltering candidacy for days, reluctantly agreed.

"Owen came to the conclusion that he would not be able to win in a three-party race," said Tim Ridley, Pickett's campaign manager. "He didn't want his campaign to be the occasion to tear the Democratic Party apart."

Ridley and Robb staffers insisted today that the governor did not force Pickett out and even offered to stick by him if he continued in the race. But, party leaders privately described the withdrawal as the first step in a Robb-orchestrated "package deal" that will unfold with the expected announcement by Wilder that he will not run. Wilder could not be reached for comment today.

According to Sydney Kellam of Virginia Beach, a one-time power in the Byrd organization and longtime confidant of Pickett's who attended the Monday meeting, Robb strongly hinted that Pickett's withdrawal was Wilder's price for dropping his threatened independent candidacy. "If you get out, I don't believe that he Wilder will run as an independent," Robb told Pickett, according to Kellam.

A secretary at Wilder's law office said the senator will have no comments until his press conference at 8:30 a.m. Wednesday morning. Robb issued a brief statement praising Pickett for "an unparallelled act of political courage."

"It is with a profound sense of personal sadness that I concur in his judgment that this action is necessary to bring our party and our commonwealth back together," said the governor.

Despite the effusive praise, the withdrawal of Pickett was viewed as a setback to Robb, who had selected the bland Virginia Beach state legislator after a series of closed-door meetings this winter that critics likened to machine politics.

It also leaves the Democrats with no announced candidates for the Senate with only one month to go before the party nominating convention in Roanoke. Some Democrats noted today that whoever ends up the nominee may face a severe handicap in terms of fund-raising and name-recognition, especially given Trible's now huge head start.

At least four names were being touted today as probable contenders--Lt. Governor Richard J. Davis of Portsmouth, Senate Majority Leader Hunter B. Andrews of Hampton, Commonwealth's Attorney Robert F. Horan of Fairfax County, and former state attorney general Andrew P. Miller of Alexandria. But all seemed contingent on Wilder staying out of the race.

"If Sen. Wilder indicates that he's not going to run as an independent, I would probably be interested," said Horan. "If he indicates he is, I don't think the Democratic nomination is worth three and one-half cents . . . That would assure my sitting on the sidelines."

Davis, who has previously stated he would not want the nomination if Wilder runs, was in Chicago and will have nothing to say until he returns this weekend, according to an aide. Andrews and Miller both refused to comment on their plans today, although Miller said if Wilder withdraws, "It clearly would be a whole new ball game."

The ball game was supposed to have ended in February when Robb and other party leaders selected Pickett as the potential candidate who would give the Democrats their best shot at a Senate seat since 1970 when Byrd switched from a Democrat to an independent. All the potential Democratic candidates had agreed beforehand that the party should avoid a divisive nominating fight.

And on paper, Pickett seemed to fit the bill--a 51-year-old Virginia Beach lawyer and certified public accountant, he had compiled a moderately conservative record in the House of Delegates that had not offended any element in the party. More importantly, perhaps, Pickett had been the party chairman during Robb's smashing victory against Republican J. Marshall Coleman last year and was credited with recasting the party in a more conservative mold.

Although virtually unknown statewide and plagued by a colorless personality, he was, as one party leader had put it, the candidate with "the least negatives."

His campaign got off on the wrong foot when he formally announced in March and invoked Byrd's name, thereby offending Wilder and other blacks who see Byrd as a symbol of the state's segregationist past. Since then, as the Wilder threat has grown, Pickett's campaign stumbled from one crisis to another.

Because he was the only candidate, Pickett managed to capture 1,914 of the delegates to the Roanoke convention--or 164 more than needed for the nomination--during a series of sparsely attended mass meetings throughout the state earlier this month. But fund-raising was agonizingly slow--he had raised only $40,000 on his first campaign finance report last month--and rank-and-file party members grumbled privately about his lackluster performance on the stump last week. One Fairfax Democrat who attended a Pickett speech likened the experience to "watching the grass grow."

Last week, in a last-ditch effort to coax Wilder back into the party fold and silence criticism that he was hand-picked by party bosses, Pickett released the delegates, saying they were free to vote for whomever they pleased. But Wilder refused to drop his threat, calling Pickett's action a "total empty gesture." At a press conference the next day Robb appeared to hedge his support for Pickett, insisting that his commitments were unchanged, but turning aside questions about whether he would switch his support later on.

Today, Pickett put out a formal 2 1/2 page statement, but was unavailable for any questioning by reporters.

"I began my campaign . . . in the belief that, this year, the opportunity to elect a Virginia Democrat to the United States Senate has never been greater," he said. "Nevertheless, the events and developments of recent weeks have convinced me that there may be others more able to unify the Democratic party and reassemble the coalition that contributed so mightily to last year's success."

Ridley said that, after approving the statement, Pickett had decided to spend the day sailing on the Chesapeake. "To say he's disappointed--I don't think that word does justice to it," he said.