Why does the Torah repeat "Ad Boker"?
Rashi #1: "Boker" per se, implies sunrise, so the Torah repeats it to teach us that the meat becomes Nosar already from dawn break.
Rashi #2 and Targum Yonasan: To teach us that what is left over until the morning (of the fifteenth) may only be burned on the morning of the sixteenth. 1
Since one may not burn Kodshim (that may not be eaten) on Yom-Tov (Targum Yonasan). See also Ba'al ha'Turim.
What are the ramifications of the fact that the Torah places the prohibition of leaving over from the Pesach and burning the leftover in the same Pasuk?
Rashi (in Pesachim, 63a): It teaches us that it is only parts of the Pesach that are edible and that one failed to eat that need to be burned. 1
To preclude the bones, horns, hoofs and the like.
Rashi writes that "Boker" implies sunrise. It says in Rus (3:14) "va'Tikach ba'Boker b'Terem Yakir Ish Es Re'ehu." This cannot be after sunrise, for then people recognize one another!
Moshav Zekenim: There, the verse reveals that it is before sunrise, but Stam Boker is after sunrise.