Charles Theokas has resigned as commissioner of the Atlantic 10 to become director of athletics at Temple University, a member of that conference.

Theokas, 47, succeeds Gavin White Jr., who resigned to return to teaching at Temple. Theokas was an executive of the NBA's New Jersey Nets and USFL's New Jersey Generals before being appointed Atlantic 10 commissioner in 1984 . . .

Bob Boyd will resign as basketball coach at Mississippi State and make his decision official just before tonight's Southeastern Conference opener with Alabama, sources said. A 7 p.m. news conference has been set.

University President Donald Zacharias said the resignation was "not anything unexpected. . . . He has been planning to make a career decision for some time."

Zacharias said he understood that Boyd, coach since 1981, and Charlie Carr, the new athletic director, had talked in New Orleans. Mississippi State is off to a 3-6 start this season . . .

An advisory group at Dartmouth has affirmed the Nov. 29 firing of Joe Yukica as football coach, but not necessarily right now.

Dartmouth announced its athletic council voted 9-1 in closed session to approve the dismissal. But apparently in response to Yukica's court-upheld claim that his contract requires a year's notice for termination, the council said its fallback position is that Yukica "be relieved . . . not later than Dec. 31, 1986."