Maryland's Republican gubernatorial candidate, Robert A. Pascal, told a convention of educators yesterday that he favors tuition tax credits, and Democratic Gov. Harry Hughes, who drew louder applause, said he opposes the plan.

The rival gubernatorial candidates clashed on that issue and other education-related topics at a convention of local board of education members in Ocean City.

Pascal, the Anne Arundel county executive, said the tax credits should be limited to low- and middle-income parents and provided primarily for those who send their children to religious elementary and secondary schools.

"Once we get the public schools up to speed there won't be any problem," said Pascal, whose children attended Anne Arundel County public schools. "But I think poor people and middle-class people should have the same opportunity" to avail themselves of private schools as those with high incomes. Pascal did not give an income figure to determine who would be eligible for tax credits.

Hughes, whose children attended preparatory schools after the elementary years, said allowing the tax credits would raise concerns about the separation of church and state, especially if used for those attending religious schools.

The credits would be given on property tax, a main source of funding local public schools. The idea has been pushed by private schools and others as a way to compensate parents of children in private schools for taxes they pay for a public school system they don't use. Public school advocates have long felt that such credits would undermine the nation's free educational system by encouraging an exodus to private educational institutions.

On most other issues discussed before the school board members, many of whom were appointed by Hughes, the two candidates demonstrated similar positions: Both agreed that the state must pick up the cost of special education programs cut by the federal government; both said they had no quarrel with allowing voluntary prayer in public schools, and, after the forum, they agreed that busing for school desegregation has not worked. However, while Pascal said he was opposed to busing, Hughes said he would take a case-by-case approach on the busing issue.

The two men also differed on whether to allow teachers' unions -- or by extension, any state employes union -- to have an agency shop. Under such arrangements, a union may charge dues of all employes in its bargaining jurisdiction, not just union members.

Hughes, who won the endorsement of several teachers' organizations, said he does not support agency shop provisions. Pascal, who has been frustrated in trying to persuade labor to back a Republican in this race, said he endorses agency shop clauses.

"If a union represents people at the bargaining table they should decide who pays dues and how much," the GOP candidate said.

Despite Pascal's support of that union cause, he suffered a disappointment earlier in the day when the executive board of the AFL-CIO, the state's largest and most influential labor group, endorsed Hughes.

Early in the campaign, Pascal held out hope that he might be able to persuade the AFL-CIO to withhold an endorsement in the gubernatorial race, and he spent much of the summer wooing labor leaders in the city. But by yesterday morning, when both candidates presented their views to the union at a meeting in Baltimore, the Pascal people had all but given up hope and were "leaking" word that delegates to last night's meeting had not been properly certified.

That charge was denied by AFL-CIO leaders, and later in the day another Pascal supporter admitted that there was no reason for the union leadership to try to stack the vote. "They've got the votes for Hughes, it would be foolish for them to do anything illegal," the source said. "But Pascal does have some support in that union. It is not unanimous."

Pascal's chance for endorsement by the AFL-CIO apparently was hurt with the selection of Newton I. Steers as his running mate. "Pascal had a chance with a lot of groups in the union until people started talking about the No. 2 guys," said one source. The union helped defeat Steers two years ago in his bid for reelection to Congress from Montgomery County.

After Hughes and Pascal spoke, the 35-member executive board met and, according to sources, voted by acclamation to endorse Hughes.

The two candidates appeared together again last night at a B'nai B'rith function in Chevy Chase. Pascal's wife Nancy wore a Star of David around her neck for the occasion.

This time the subject matter was more general and the candidates engaged in some fairly sharp exchanges on the subjects of prison, a cabinet-level officer for the aged and economic development.

Hughes, who had been briefed by his staff over a prime rib dinner after an earlier appearance at a fund-raising event for Montgomery County Executive Charles W. Gilchrist, called Pascal's proposal for a cabinet-level position to represent the elderly "cosmetic." He also defended his administration's prison policies after Pascal criticized him again for moving too slowly to build new prisons.

Both men appeared relaxed and satisfied at the end of the long day, each feeling he had scored some points but knowing they would have several more opportunities to air their differences again before Nov. 2.