So I was reading in FMA recently and noticed that the Führer President King Bradley brings a melon with him when he comes and sees Edward in the hospital. I have noticed this in several other animes and mangas and was wondering what the origin of the trope is.
The origin of this is actually in real life.
In Japan, melons are considered to be a rather expensive fruit, and after often given as gifts, specifically when visiting someone in a hospital. I'm not really sure how this particular notion was started, just that it is a common thing nowadays.
In fact, here is a 21,000-yen (~$210) melon:
It would seem that the anime and manga that feature this idea are simply drawing from this part of Japanese culture.