President Carter and Israeli Prime Minister Menachem Begin last night broke off their Middle East peace discussions in Washington because "there was not much fruit in this round," informed Israeli government sources here said early today.

"This round of talks hasn't achieved much, are going to think for a wile," an Israeli Foreign Ministry source said.

He said the decision was made last night at a private dinner in which Carter and Begin discussed the Middle East stalemate for two hours, after which Begin presented a summary of the differences and suggested that there was no point in continuing the discussions now.

Begin's press secretary, Dan Patir, told a Washington correspondent of Israel Army Radio that the recess was not a breakoff of negotiations but was made to give both leaders time to consult with their advisers. It was apparent, however, that at least this round in the complicated set of talks was a failure.

Israeli sources said Begin will stay in Washington today to consult with congressional leaders. He is expected to go to New York Monday to meet with American Jewish leaders and probably will return to Jerusalem on Wednesday, sources said.

Earlier, staff writer Edward Walsh reported the following in Washington:

Carter for the first time offered Begin a series of American suggestions to break the impasse with Egypt.

Before the critical meeting, American officials, headed by the president and Secretary of State Cyrus R. Vance, spent most of the day developing the ideas that were presented to Begin last night.

But there was no attempt by any of the officials involved to gloss over the impression of deep pessimism that was left after the first two Carter-Begin meetings, during which no progress was made in bridging the remaining differences between Israel and its Arab neighbor, Egypt.

Among the officials Carter conferred with during the day was Defense Secretary Harold Brown, giving rise to speculation that the U.S. suggestions to Begin could include possible additional American measures to guarantee Israel's security.

A U.S. official confirmed that the American delegation was exploring ways it could offer such peace-treaty incentives to both Israel and Egypt.

"In the context of a peace treaty and the stability that would bring to the whole region, there is just a whole range of things we could do for both Israel and Egypt that can't be done without a peace treaty," the official said.

In the past, ther have been suggestions of a mutual defense treaty between Israel and the United States or of establishing an American military base in the region. Sources said military bases were not being discussed, but it could not be learned what other ideas were being considered by the American delegation.

Begin and his wife, Aliza, arrived at the White House north portico at 7 last night and were greeted at the door by the president and his wife, Rosalynn. Smiling and apparently in a good mood, Begin ducked a reporter's question on whether he was prepared to hear some "new ideas" from Carter.

"Well, we have come to have dinner," he said. "It is an invitation for which we are grateful."

"The menu is already fixed," the president said.

U.S. officials yesterday contined to refuse to discuss the substance of the discussions, and the first clear assessment of where they stand is not likely to be made until today, when Begin is scheduled to appear on the television interview program "Issues and Answers" (ABC, WJLA).

The television appearance was Begin's idea and clearly not the preference of American officials, who contend that any hope of breaking the negotiation impasse would be lost if there is a public debate.

Even the few public statements that have been made by Carter and Begin have illustrated the lack of progress, with the president calling the remaining issues "insignificant," an indication of his frustration, and Begin emphasizing their importance to Israel.

U.S. officials yesterday denied a report in an Egyptian magazine that Sadat was planning to travel to Washington Tuesday, Carter, it was said, has not spoken with Sadat since he began the talks with Begin Thursday night.

The pessimism surrounding the talks was based on the clear signs of stalemate after the first 4 1/2 hours of discussions. A meeting Friday that included top advisers from both countries, it was learned yesterday, was devoted largely to a restatement of the Israeli position on the outstanding issues. The American delegation made a few preliminary suggestions for resolving the differences, but the Israelis reportedly showed no interest.

After this initial rejection, the U.S. delegation concentrated yesterday on developing additional ideas officials hoped might attract Israeli interest and provide a basis for continuted negotiations.

It could not be learned last night what the president proposed to Begin, but it was known that the U.S. effort focused on the two most important disagreements over peace treaty language between Israel and Egypt.

One of these disputes involves Egypt's insistence that a peace treaty with Israel encompass a timetable and a target date for completing separate negotiations leading to Palestinian autonomy in the Israeli-occupied territores of the West Bank and the Gaza Strip.

The other dispute ceters on Egypt's objections to a provision in the draft treaty that would give the agreement precedence over other Egyptian accords with Arab nations of the Middle East.

Egypt has adhered to these positions thus far, and the U.S. effort has concentrated on seeking signs of Israeli willingness to seek a compromise. The United States, for example, is understood to have recommended a one-year target date for completing the autonomy talds.

Last night's dinner at the White House was the second in two nights shared by Carter, Begin and their wives. Friday night at Blair House, Begin hosted a traditional Sabbath evening dinner for the president and high-raking U.S. officials.

Wearing a white skull cap, Carter clapped his hands to the beat of Israeli folk songs and bid Begin "Shabbat, shalom (Sabbath, peace)" at the dinner's end.

Following that dinner, Begin met into the night with his advisers and a U.S. official said the American delegation "will certainly make an effort to explore ways, ideas, to bridge the gap."