Virginia Gov. John N. Dalton, bowing to intense pressure from conservatives, today vetoed a bill that would have made Virginia the first southern state to honor slain civil rights leader Martin Luther King with a state holiday.

Dalton said in a statement that he vetoed the bill because it would have eliminated Election Day as a state holiday and because he said it would be "more appropriate" to honor native Virginians such as Thomas Jefferson, Patrick Henry or Booker T. Washington.

But black leaders accused the governor of insensitivity to the state's black community and noted that Virginia has a state holiday honoring Confederate generals Robert E. Lee and Stonewall Jackson. They also said Dalton was appeasing conservatives who had contributed large sums to his 1977 campaign.

"he told me 'King has been honored enough,'" said L. Douglas Wilder of Richmond, Virginia's sole black state senator and sponsor of the King holiday measure.

"The governor just knuckled under," said the Rev. Curtis Harris, president of the state unit of the Southern Christian Leadership Conference, the civil rights group King founded. "I think the racist attitude of our state has overwhelmed him."

Dalton today also vetoed two controversial bills that would have allowed state Medicaid funding of abortions in cases of rape, incest or gross fetal abnormality, saying only he did not "approve of using tax dollars through Medicaid for the purpose[s]" of the two bills. Supporters of the measures had held out hope that the governor would at least sign the bill allowing the operations for rape and incest victims.

The governor's vetoes can be overruled by a two-thirds vote by both legislative houses. The 140-member General Assembly is schedule to reconvene next week for the first override session in the state's history, but several lawmakers said today they believed all three bills would likely fall short of the votes needed to override.

The King bill would need 11 more vots in the 100-member House of Delegates and three more in the 40-member Senate than it had in the regular session to gain the necessary two-thirds margin. The rape and incest abortion bill, the Medicaid measure most likely to win an override, was six votes shy of the two-thirds margin in each house when passed earlier this year.

The King and the abortion bills had generated massive letter-writing campaigns that Dalton said produced more letters "than any other issues since I became governor." Press Secretary Charles Davis said the governor received about 7,500 letters, most of them urging him to veto the measures.

Letters on the King bill came from two groups, old-guard conservatives led by former governor Mills E. Godwin, who vetoed a similar measure in 1977, and the remnants of segregationist groups that were the foot soldiers of the state's Massive Resistance movement in the 1950s.

"It wasn't a question of race with me but I just think we don't need any more holidays," said Richmond insurance executive J. Smith Ferebee, an opponent of the bill and a major donor to Dalton's 1977 campaign. "Besides, King wasn't a Virginian. If blacks really wanted to get a holiday for Booker T. Washington they'd get it."

Some opponents attacked King, who preached nonviolent civil disobedience as a weapon against segregation, as a Communist sympathizer and revolutionary. a

"Praise God," said Mary L. Curtis, a Fairfax housewife and mother of four when she heard of Dalton's veto. Curtis lobbied against the bill and helped put together what she called an "ad hoc committee" of about 100 people opposed to the holiday. Curtis distributed to Dalton, state legislators and the press a packet of reprinted magazine articles, editorials and excerpts from FBI files alleging links between King and communism, and accusing King of advocating violent overthrow of the government.

"I oppose it based on his record, not his color . . . he was a tool of the Communists," said Curtis, who said she worked with members of the United Daughters of the Confederacy and the Sons of Confederate Veterans in fighting the holiday. Former members of a now-defunct segregationist group, the Defenders of State Sovereignty, based in Southside Virginia's Prince Edward County, which defied court-ordered school integration by closing its public schools for five years, also were said to participate in the letter-writing effort.

The bill, which Wilder sponsored, passed the Democrat-controlled legislature this year amid speculation that some Democrats had supported it in an effort to embarrass Dalton and state Attorney General J. Marshall Coleman, the GOP's likely gubernatorial nominee. And many predicted today that the bill is likely to become a major campaign issue in the contest between Coleman, Virginia's attorney general, and Democrat Charles S. Robb. Coleman today supported Dalton's veto, saying King's birthday should continue to be coupled with New Year's Day on Jan. 1, as approved by the legislature and approved by Dalton in 1978.

Robb, the state's lieutenant governor who in the past has been reluctant to criticize Dalton publicly on state issues, said he would have signed the bill. "Symbolically it means a great deal to significant number of Virginians and it wouldn't have cost the state any money," Robb said. "I think the governor missed a real opportunity."

Coleman's support for the veto is likely to help Robb consolidate his support among black leaders, many of whom had been reluctant to commit themselves to the Robb campaign because of his conservative views. At the same time, it is likely to cost Coleman many of the black votes he received in 1977, when he got almost a third of black voters in his contest against conservative, former segregationist Edward Lane.

"If Coleman takes that position [supporting the veto], he can write off the black vote," said SCLC's Harris, who publicly supported Coleman in the 1977 contest.

The sponsor of the Medicaid abortion bills, Suffolk Del. Samuel Glasscock, said Dalton told him today he vetoed the measure because he did not want to authorize any new programs for the state's deficit-ridden Medicaid budget and because "a lot of people feel strongly about this."

Glasscock said funding the abortions would have cost less than $20,000 annually and would have been cheaper than paying for deliveries and further medical care. "How the state can stand by and let rape and incest victims suffer is absolutely beyond me," Glasscock said.

Marjorie Higgins, lobbyist for the Virginia Human Life Society, part of a coalition of antiabortion groups opposed to the bills, hailed Dalton's vetoes as demonstrating that "the national mood has changed . . . psychologically and symbolically they're very great victories."