Musa aurantiaca G.Mann ex Baker, Ann. Bot. (Oxford) 7: 222 1893.; 
Assam; East Himalaya; Myanmar; Tibet as per Catalogue of Life;

Loc.: Upper Siang distt., Arunachal Pradesh
Date: Oct., 2005

… , nice shot. But regarding species ID, I think it is Musa aurantiaca Baker, M. sikkimensis is entirely different one.

Thanks for your comments! I may be wrong but my plant also not completely matching with the description of M. aurantiaca. There are differences in habit, leaf characters, petiole size, inflorescence characters and bracts. Attaching a PDF and some more pictures for your kind perusal. Hope we can find its correct identity.

Attachments (1)- Musa.pdf

It is Musa aurantica for sure.
I got the confirmation from Prof. M. Sabu (Presently revising the family Musaceae in India)

It is M. aurantiaca