seminar topics
 

Could anyone please tell about the hot topics in linux........

Nope. What sort of hot topics? Topics on programming, drivers, kernels, flame wars, the latest saying of Linux??? What exactly are you after here?

to know about latest developments in anything related to linux...kenel,programming,new software........

Your best bet is to pick the subjects you are most interested in and subscribe to their mailing lists - particularly developer lists. That way you will be abreast of developments as they are happening.

Given that the title of the thread is "seminar topics" it seems to me that you need to start by understanding who the proposed audience for the seminar(s) is. That will help you focus in on what THEY are interested in.