The delicate screening of individual prospective jurors began today in the political corruption trial of Maryland Gov. Marvin Mandel with four of the five persons interviewed winning preliminary approval as jurors.

After a full night's rest, Mandel arrived looking refreshed for the second day of his retrial, long delayed by an apparent small stroke he suffered in April. Mandel "went home and went straight to bed," Wednesday after a day that saw him fall to the courthouse steps as he entered for the trial, said his wife, Jeanne Mandel.

"He was badly shaken up - and embarrassed - by what happened yesterday," she said.

One of Mandel's five codefendants - Irvin Kovens - went home early today saying he was under doctors' orders to relax. Kovens was excused from the first trial, which ended Dec. 7 in a mistrial, after claiming a heart ailment.

"He went home and went straight to bed," said Mrs. Mandel. "The doctors phoned last night and talked to him. He was badly shaken up - and embarrassed - by what happened yesterday."

U.S. District Judge Robert L. Taylor completed the open-court screening of some 230 prospective jurors this morning before he began the time-consuming interviews of individual jurors. The first person selected was a retired steelworker who won approval of the defense team and federal prosecutors after a 45-minute grilling. Questioning of the other four persons took up the entire afternoon session.

Taylor plans to hold court on Saturday to accelerate the selection o f a pool of 43 potential jurors from which the final 12 jurors and six alternates will be selected.

"It is not unusual for citizens to keep up or express views on matters of public importance," the judge told the prospective jurors before they filed out to wait their turn. "But do not discuss this case with anyone, do not listen to any broadcasts about the case and do not read newspaper stories about the case."

Since the first attempt to try Mandel and his five co-defendants ended in a mistrial because of two outside attempts to influence the verdict, the court has taken special precautions to insure that this will be a clean panel of jurors.

Unlike the last trial when jurors were allowed to go home each evening, this jury will be sequestered in a Baltimore area hotel with privileges to visit family members only and in a supervised situation. Also unlike the last trial, the list of prospective jurors has been sealed until the final selection is made.

In this morning's open court session Taylor, a frail and bald jurist called in from Tennessee to hear the case, asked a shifting series of questions to groups of boarding prospective jurors. Political attitudes, roles in political campaigns, and connections to the horse-racing indutry were among the questions used to sort out qualified.

The state's control over horse racing is one of the key elements in the U.S. governement multi-count charge of a corrupt relationship between Mandel and his five friends and codefendants, Kovens, W. Dale Hess, Harry W. Rodgers and his brother William A. Rodgers, and Ernest N. Cory Jr.

In the last trial, the prosecution presented testimony that Mandel received gifts worth some $200,000 from these men allegedly in exchange for his efforts in favor of legislation to benefit the Marlboro Racetrack, a now defunct half-mile course in Prince George's County.

Since the mistrial, 57-year-old Mandel suffered what his physicians believe was a mild stroke that caused a two-month delay in the trial. Today Mandel appeared alert and in good humor as he sat through the morning selection process.