I believe that the yellowing of the foliage is related to the damage to the trunk. The trunk of your peach tree has pretty extensive injury. I see what looks like a decay fungus growing adjacent to the wound and bark that may have borer holes in it. Some of the bark below the open wound appears to not be solidly attached, so the wound may be even large than what is immediately apparent. The injury is reducing the normal flow of water and nutrients within the tree. As I mentioned, there might also be borers present. All of there could be contributing to the chlorotic appearance of the leaves.