I 'think' (I'm just using that rose bush, from experience), the characteristics and genetics would match the particular branch the sample came from ... in grafting, you're just 'sticking two different plants together' ... they are being nourished by the same source, but,you're not altering their genetic code, (at least, that's my way of thinking) ... ...
I can't think of a reason to graft cannabis plants together ... I really can't :jointsmile: