Following are excerpts from President Carter's comments on the B-1 bomber and other issues raised at yesterday's press conference: THE B-1

This has been one of the most difficult decisions that I have made since I have been in office. During the last few months, I have done my best to assess all the factors involving production of the B-1 bomber.My decision is that we should not continue with deployment of the B-1, and I am directing that we discontinue plans for production of this weapons system. The Secretary of Defense agrees that this is a preferable decision, and he will have a news conference tomorrow morning to discuss this issue in whatever detail you consider necessary.

The existing testing and development program now underway on the B-1 should continue to provide us with the needed technical base in the unlikely event that more cost-effective alternative systems should run into difficulty. Continued efforts at the research and development stage will give us better answers about the cost and effectiveness of the bomber and support system, including electronic-countermeasures techniques.

During the coming months, we will also be able to assess the progress toward agreements on strategic arms limitations in order to determine the need for any additional investments in nuclear weapons' delivery systems. In the meantime, we should begin deployment of cruise missiles using air-lauched platforms, such as our B-52s, modernized as necessary. Our triad concept of attaining three basic delivery systems will be continued with submarine-launched ballistic missiles, intercontinental ballistic missiles and a bomber fleet, including cruise missiles as one of its elements. We will continue thereby to have an effective and flexible strategic force whose capability is fully sufficient for our national defense . . . CRUISE MISSILES

There are a number of factors [in the B-1 decision]. One is obviously the recent evolution of the cruise missile as an effective weapon itself. The tests of this system have been very successful so far.

Another one, of course, is the continued ability to use the B-52 bombers, particularly the G's and H's, up well into the 1980s, and the belief on my part that our defense capability, using the submarine-launched missiles and intercontinental ballistic missiles combined with the B-52 cruise missile combination, is adequate.

We will also explore the possibility of cruise missile carriers, perhaps using existing airplanes or others as a stand-off launching base.

But I think in toto the B-51, a very expensive weapons system, basically conceived in the absence of the cruise missile factor, is not necessary . . . CAMPAIGN PROMISES

Well, when I went into office, as I think I said earlier, I tried to take the position of complete open-mindedness, because obviously I have had available to me as President much of the classified analyses and information about weapons systems which I did not have before. And I tried to approach this question with an open mind.

I have spent many hours reading those detailed technical reports, the advice of specialists on both sides, the analysis of ultimate cost of weapons. Although, obviously, opinions are always hard to change, I deliberately tried not to let my campaign statements be the factor in this decision. I have made it, I think, recently with an original, very open mind, after carefully considering all aspects of the question and consulting very closely with the Secretary of Defense.

I might say with the advent of the cruise missile as a possible alternative, that the Secretary of Defense agrees with me that his is a preferrable decision . . .

I will always try to keep an open mind and make a decision on what I think is best for our country. MIDEAST

An overwhelming consideration for us is the preservation of Israel as a free and independent and, hopefully, peaceful nation. That is preeminent. At the same time, I believe it has been good during this year, when I hope we can reach a major step toward a peaceful resolution of the Middle East . . .

"I believe all the issues are fairly clearly defined. It is accurate to say that our own nation has no plan or solution that we intend to impose on anyone. We will act to the degree that the two sides trust us in the role of an intermediary or mediator, and I still have high hopes that this year might lead toward peace.

"But it will never be with any sort of abandonment of our deep and permanent commitment to Israel. And I have made this clear in specific terms to every Arab leader who has been to our country . . ." PANAMA CANAL TALKS

I hope that we will have a successful conclusion of the talks this summer. We have been encouraged so far. The major questions that were identified at the beginning have fairly well been concluded.

One of the disagreements at this point is on the payment of portions of the tolls from the Panama Canal to Panama and the exact financial arrangement.

But I hope still that we have one by summer. CHINA

Our attitude on the Chinese question has been spelled out by my predecessors and confirmed by me as based on the Shanghai Communique, which acknowledges the concept of one China.

We also hope that Taiwan and the mainland can work out the differences between them.

We obviously hope that these differences can be resolved early, or perhaps in the future through peaceful means.

My hope is that we can work out an agreement with the People's Republic of China having full diplomatic relations with them and still make sure that the peaceful lives of the Taiwanese, the Republic of China, is maintained. That is our hope. That is our goal . . . MONOGAMY

My preference is that those who associate with me - in fact, all people - would honor the same standards that I honor. But I have never held it against people who had a different standard from myself. I have done everything I could properly and legitimately to encourage my staff members' families to be stable, and I have also encouraged the same sort of thing in my Cabinet.

If there are some who have slipped from grace, then I can only say that I will do the best I can to forgive them and pray for them . . .