Somebody as versed in the English Language should have no problems with using a dictionary. However, in case you don't have this ability, the following link should help:

http://www.dictionary.com/cgi-bin/dict.pl?term=marketing

With respect to in v. on, both are prepositions. I have always taken in to mean as far as this conext is concerned, "within the bounds or limits of something". On shows location. Of course, in can show location as well. In this case, my major was in the bounds and limits of MIS. Or more briefly, my major was in MIS. On however, can be about a specific concern. The dictionary illustrates this with the example of a "book on astronomy." I suppose you could say a major is concerned with something, thus majoring on something. It does not sound right to me. The same flow is not present.

As far as in being reflective of bad grammer here as opposed to on, I cannot buy into that assertion. At least, I find no absolute rule here. I could also argue that if something does become the accepted norm, that is the correct way. For example, a law on the books that is not followed is by definition, not a law. A law or rule is only valid to the extent it is both documented and enforced.