The Virginia House of Delegates yesterday gave preliminary approval to a bill that would require that the party identification of all candidates be listed on election ballots.

The measure has been introduced three times in the last three years, but it is the first time it has advanced this far.The bill was introduced by Del. Richard R.G. Hobson (D-Alexandria), who said that all but Virginia and Nebraska require that candidates be listed by party.

Under the bill, candidates running for the same office would be grouped under a party identification label on the ballot. The order in which the parties appear on the ballot would be determined by lot.

The measure must now win final approval in the House and then be approved by the Senate.

Party designation on ballots has been defeated in the General Assembly before, largely on the strength of votes by conservative Democratic members.Many of these legislators in recent years have been wary of association with national Democratic tickets. The national ticket has carried Virginia only once since 1948. The party affiliations of candidates running for president and vice president already are listed on Virginia ballots.

Opponents of party designation usually argue in Assembly debates that it is no more appropriate to print party labels on ballots than it would be to print a summary of a candidate's political philosophy.

Virginia also does not provide for voter registration by political party.

In other action, the House gave preliminary approval to a controversial bill to allow teachers to appeal a dismissal before an independent fact-finding panel. Under the new provision, the teacher would be allowed to be heard before the fact-finding panel, or the school board as is now the case, but not before both.

The fact-finding panel would be composed of three members, one chosen by the teacher, one by the school superintendent and the third mutually agreed upon by the teacher and the superintendent. The proposal is controversial because it slightly expands the grievance procedure for teachers. To many House members this smacks of collective bargaining, which has been outlawed in Virginia by the state Supreme Court.

A Senate subcommittee studying proposed changes in the state's sexual assault laws yesterday heard Fairfax Commonwealth's Attorney Robert F. Horan Jr. attack the proposals as being unnecessary.

While supporting provisions that would require testimony about a victim's sex life to be held in a closed hearing so that a judge could decide if the testimony was relevant, Horan objected to other parts of the measure.

Horan, representing the Virginia Association of Commonwealth's Attorneys, criticized the proposed elimination of aprovision that prohibits sponsors from accusing each other of felony sex offenses.

"We foresee a potential area of abuse by wives getting a divorce and then accusing their former husbands of sexual assault," Horan said. "There is a great deal of difference between a woman who has been married to a man for several years being forced to perform sexual intercourse. The degradation is not the same as with some stranger."

Horan said that in his years as a prosecutor he has not encountered a rape case that was "lost because of the existing law. Cases are lost on the facts."

Horan also said the revisions, which would constitute a major overhaul of the state's sexual assault laws, would be "a bonanza for defense attorneys" because "it would be a brand new body of law to be determined on a case by case basis."

In another development, the Senate Agriculture, Conservation and Natural Resources Committee, killed two bills on 8-to-6 votes that would have required deposits on beer and soft drink bottles throughout the state.

The committee voted to reconsider the bills next year.

One of the senators who voted against the bills, Frederick C. Boucher (D-Abingdon), said he would not consider supporting a statewide container law until 1980 - after a state survey of the effectiveness of the state's Litter Control Commission, which only recently began an antilitter educational program.

Yesterday's committee action was the second major defeat for deposit advocates in this session. Last week the House passed and sent to the Senate a bill that would abolish Fairfax and Loudoun counties' ordinances requiring deposits on soft drink bottles and prohibit other localities from enacting such legislation.

In still another matter, Gov. John N. Dalton told House and Senate members that based on more optimistic economic forecasts, the state expects to receive another $34.1 million in tax revenues in the second year of the proposed 1978-1980 budget.

Tax Commissioner William H. Forst said the increase was "not a major amount." About $27 million of the $34.1 million would come from individual and corporate income tax revenues. Even so, the increase in those revenues would amount to less than 3 percent above the previously projected total for the second year of the budget.

Dalton recommended to the legislators that $25.8 million of the $34.1 million be used to move up the proposed 4.8 percent cost-of-living increase for state employes from Jan. 1, 1980, to July 1, 1979.