Maryland Gov. Marvin Mandel, proclaiming that "I love this state too much" to have broken the public trust, vigorously denied allegations of corruption today in his first day under cross-examination.

The governor surprised chief prosecutor Barnet D. Skolnik by dramatically producing a photocopy of an agreement he said he penned over dinner at Duke Zeibert's Restaurant in 1973 in which he promised to repay $155,000 to codefendant Irvin Kovens by the year 1990. The agreement was meant to show that the money from Kovens - in the form of municipal bonds to help Mandel with his divorce settlement - was a loan, not a gift, as the prosecutors have alleged.

The $155,000 amounts to nearly half of the gifts and favors that prosecutors allege Mandel received for using his office to help their from five codefendants in exchange business interests.

Arnol M. Weiner, attorney for Mandel, wound up his questions to the governor by asking if Mandel had devised a scheme to defraud the citizens of Maryland.

"No sir!" Mandel boomed out, "I have been in public office since 1952, Mr. Weiner . . . If I have ever done anything, it is for the benefit of the state and the benefit of the people. I love this state too much to have ever done anything like that."

Cross-examination then began.

Unlike his performance on Friday, when Mandel had to ask for a brief recess because of his recent illness, the governor today showed a spark and vigor that was lacking throughout the trial. He answered questions with confidence and spunk, exhibiting that colored his previous testimony.

Only once, after Skolnik had placed a transcript on his tap, did Mandel make apparent reference to his illness. He asked Skolnik to take the transcript off his lap because "it's hard for me to hold it."

After reading the Duke Zeibert's memo, which was not witnessed or typed and had been withheld during Mandel's defense, an incredulous Skolnik asked the lawyer-governor "This is your legal obligation to pay Mr. Kovens . . . and it was handwritten at Duke Zeibert's?"

"That's correct, sir," Mandel answered.

"We were sitting, just Mr. Kovens and I. havening dinner at Duke's Mandel said. "It had been a highly emotional day . . . full of strain and stress. I wrote that . . . I didn't carry a typewriter with me, sir, I carried a pen and I used a pen."

The original of the agreement was not produced today, although Skolnik sought access to it in an exchange typical of the day.

Skolnik - Could you please - I don't mean right this miute, but after court, if you could, sir. I'd appreciate it if you could obtain the original of that document for us. Could you do that for us?

Mandel - Would I obtain it for you?

Skolnik - Yes, sir.

Mandel - You will have to talk to Mr. Kovens' attorney. I'm not his attorney, sir.

Skolnik - Well, for legal reasons, sir, I am simply requesting you do that . . . You don't have the legal problems I do in doing that."

Mandel - Well. I don't have any problems talking to Mr. Kovens, but I have no legal obligations to produce Mr. Kovens' records.

Together, these bonds for Mandel's divorce account for almost half of the $350,000 worth of gifts that the prosecution alleges Mandel received from his codefendants as part of a scheme to defraud the citizens of Maryland.

The first of at least two days of Mandel's cross-examination produced few other new claims, only a deeper shading of Mandel's denials of major prosecution charges and new questions about Mandel's finances.

Skolnik opened his examination with a detailed inquiry into just how (Mandel's earlier words) governor actually earns). Mandel admitted he does not pay rent, transportation cost, few food or drink costs, or even yachting expenses out of his $25,000 salary, which he implied on Friday forced him to accept gifts and loans.

He also contradicted testimony from State Sen. President Steny H. Hoyer (D-Prince George's) who had said in the mistrial last December that he had alerted the governor to rumors that his codefendants." W. Dale Hess and Harry W. Rodgers III had an ownership interest in the Marlboro Race Track in 1972.

The track, the centerpiece of the prosecution's case, won handsome profits from legislative action that year, actions the governor denied he took a role in for his friends and codefendants who then secretly owned the half-mile course in Prince George's County.

Besides repeating denials that he knew of the secret track ownership of codefendants Hess, Rodgers, his brother William A. Rodgers, Ernest N. Cory and allegedly Kovens, Mandel made his strongest denial yet about $54,000 worth of loans from the Pallottine Fathers Catholic order.

Prosecution witnesses told the jury that the Catholic fathers laundered the loans through at least three different parties and the mission head was present when Mandel picked up his first $42,000 check at a small crab feast.

"My understanding was that at that time they (the Pallottines) were not in a position to make a loan . . . they were not going to be involved."

Mandel's repeated use of the phrase "not involved" and his knack for answering questions with an indirect response was reminiscent of his press conference read during the prosecution's phase of the case.

After reciting Mandel's free use of the "Maryland Lady", the luxurious state yacht, his free governor's mansion, with its servants, his state helicopters, food and drink, Skolnik said: "In fact, you don't pay for any of that, do you, sir?"

"Only when I pay my taxes, Mr. Skolnik, Mandel replied. In fact, Mandel volunteered, others use his yacht like oil executives.

When Skolnik pointed out that millionaire Kovens gave Mandel the bonds as well as underwrote his divorce, he asked Mandel what constituted the "exchange of gifts" the governor claimed he made.

"The greatest gift Irvin Kovens gave me was his friendship," Mandel answered.

After Mandel surprised Skolnik by revealing his written agreement with Kovens, the prosecutor focused on another charge essential to the case - that codefendant W. Dale Hess gave Mandel a 4 per cent interest in the Security Investment Co., a real estate venture with a huge potential for profit.

An agreement drawn Dec. 1, 1971, assigned four-ninths of Hess' 9 per cent ownership interet (or 4 per cent) to Mandel, a transaction that the governor testified was Hess' way of paying off long-standing leal debts accumulated from Mandel the lawyer before he became governor.

The governor would not concede that the agreement gave him an equity interest in the corporation, which owns a major building at the sprawlin Social Security Administration headquarters in Woodlawn for which the U.S. government paid an annual rent to $3 million.

"No sir," Mandel said, it merely gave him four-ninths of the profit.