Edward E. Lane, the Democratic candidate for attorney general of Virginia, today ignored a call by the only black member of the state Senate for Lane to recant his support of school segregation 20 years ago.

The episode at a Capitol Square political rally threatens to weaken the coalition of liberals and conservatives that Democrats are putting together to support their state for statewide office.

Lane has said repeatedly that he now agrees with court determinations that school segregation was legally wrong, but says he will never admit that Virginia's massive resistance to desegregation, which he supported as a legislator, was morally wrong. Sen. L. Douglas Wilder (D-Richmond), an influential member of Virginia's small corps of black public officials, asked him to do just that but got no response when Lane spoke at the rally minutes later.

Henry E. Howell, the Democratic nominee for governor and the most prominent Democratic advocate of black rights during Virginias protracted civil rights struggles, also ignored Wilder's remarks and pleaded for Lane's election.

"It would be a terrible thing," he said, "to elect me as a Democratic governor and then establish a Republican army in the attorney general's office 400 yards from my office.

"It would be like grafting a cancer onto the seven-year itch."

Today's events in the midst of a statewide tour by the Democratic ticket dramatized the fears of Democratic supporters that a controversy over Lane's segregationist background could lead not only to his defeat but to that of Howell.

The Virginia Crusade of Voters, one of the principal black political organizations of proven influence with black voters, will meet in Richmond Saturday to consider endorsement of statewide candidates.

Democratic fear that failure of the Crusade to endorse Lane or its decision to support his Republican opponent, Sen. J. Marshall Coleman of Staunton, could trigger a refusal by Lane's conservative supporters to work for Howell is considered a liberal in Virginia politics.

Lane and Howell are longtime foes within the Democratic Party but now are working vigorously to deliver their diverse factions to each other to insure the election of both. The ideological diversity of the Democratic state has led Howell to call it the "Rainbow Ticket," a name that has become the central camapign theme representing party unity. The ticket's third member is McLean lawyer Charles S. Robb, the candidate for lieutenant governor, who is the son-in-law of the late President Lyndon B. Johnson, and a moderate who appears to be less affected than Howell and Lane by old desegregation controversies.

There is an obvious irony in the potential of Lane's segregationist record to frustrate civil rights to advocate Howell in his third quest for the governorship. "Henry said the other morning that he could not sleep the night before for worrying about Lane," one Democratic campaigner said today. "He is more worried about Ed right now than he is about his own race."

Howell's opponent is Republican Lt. Gov. John N. Dalton.

There appears to be little chance that the gap will be closed soon between what Wilder and other blacks want Lane to say about his segregationist past and what Lane is willing to say.

Wilder subdued today's festive rally at the Capitol by saying in deliberate tones as Lane sat nearby, "We expect those candidates who have erred in the past to admit their errors publicly. We want them to say what is right and support what is right and we want them to say what is wrong and to tell us they are against those things.

Wilder said in an interview after the rally that Lane must go beyong a mere statement that he agrees with court decisions outlawing racial segregation and must admit that his support of segregation was morally wrong.

In an interview during a campaign flight today, Lane said he would never make such a statement. "I will not get down on my knees and ask forgiveness," he said. "To do so would be to put on me and all my friends in the Virginia General Assembly the judgment that we acted morally wrong or in bad faith. We did not and I won't say we did."

Lane has repeatedly called segregation "a closed chapter" in Virginia history and has criticized Coleman "for reopening old wounds." He said he and his political allies "did what they thought was best in a time that cannot be compared with the changed circumstances of today."

Lane's attitude clearly represents the feeling of other former supporters of segregation who are influential Democratic officeholders today.

Del. James M. Thomson (D-Alexandria), the House of Delegates majority leader who is slated to replace Lane as chairman of the House Appropriations Committee, defended his support of segregation in the 1650s in an interview today in almost the same words used by Lane.

"We did the best we knew and we shouldn't stand up now and say that we acted wrongly," he said. As recently as 1971, Thomson said he still believed school desegregation was a mistake and that events in public education had proved him right. He said today, however, that he no longer takes that position. "I have made no such statements for the last six years and that has been no accident."