Five years after antibusing violence made Boston a national symbol of racial strife, the city's school system is far smaller and blacker. Less than half as many white children were enrolled when classes resumed yesterday than before busing began in the fall of 1974.

In Dayton, Ohio, as school opened yesterday, court-ordered busing proceeded without incident -- the fourth year of busing in the 34,000-school system.

"Everything is running pretty smoothly," said Nancy Thickel, public information officer for the Dayton Schools. "There is no fighting in the schools, no bus accidents, no reports of any incidents. Overall we're off to another smooth start."

In Columbus, where 37,000 of the 79,000 students are to begin busing today, about 600 people attended an antibusing rally Tuesday night while a dozen Columbus churches held inter-faith services to pray for "social justice, peace and guidance" in the desegregation of the city's 140 schools.

In other districts the first day of school was delayed as hundreds more frustrated teachers joined 28,000 colleagues already on strike. Classes have been disrupted for more than 600,000 pupils.

Angry teachers walked picket lines in 15 states as the strikes spread from district to district.

"More teachers this year are angry about more than lousy salaries," said Susan Lowell of the 1.8 million-member National Education Association based in Washington. "They're angry about violence and they're angry at the public."

Nonetheless, demands for higher pay marked most of the disputes as teachers in Paterson, N.J.; Eugene, Ore.; Spokane, Wash.; Springfield, Ill.; Indianapolis; Portsmouth, R.I.; and parts of Pennsylvania picked up picket signs.

In Oklahoma, the state Supreme Court upheld a district court ruling barring the Oklahoma City School Board from negotiating with a teachers' union whose members are not working. But the high court ordered the district court to expedite a hearing in the dispute.

Meanwhile, school officials said 28 more teachers returned to classes, bringing the total of regular teachers on hand to 1,484. Since there are about 2,300 teachers in the district, the school board figures indicated more than 800 are still off the job.

In Pennsylvania, the strike delayed or disrupted classes for more than 47,000 students in 13 school districts. About 200 teachers struck the Pottsville School District, spreading the school closures to eastern Pennsylvania for the first time.

In Michigan, strikes spread to 37 districts with more than 10,000 teachers and 221,000 students affected. In five Illinois districts, including the 15,700-pupil Springfield system, 900 teachers honored picket lines.

Elsewhere, about 430 teachers in Southington, Conn., stayed away from first day of classes for about 8,000 students, and walkouts continued in Ohio and Vermont.