If you want to specialize in vernacular architecture after 
graduation there are a few places where you can do a 
masters course with the vernacular element as part of the 
course, and Oxford Brookes University in England is one 
school of architecture where you can do this. In fact its 
the best for this course. I am afraid I dont know in which 
universities in India you can do a masters with this 
element as a formal part of the course, but generally most 
schools of architecture ar equite flexible and allow you to 
specialise in whatever aspect of architecture you want to 
specialise in. If this is not the case in India, you will 
need to research as to which school gives you the freedom 
to do this. The other route is to do the studies in a 
conventional way and then specialise afterwards.