Extra branches

I would not bother growing a mutated seedling like this, life is too short to grow mutated seedlings! Seedlings that start off like this, usually have weird mutated buds too and end up being a waste of time in my experience. Unfortunately, not all seedlings are meant to survive. If you have heaps of room and enough "back-up" plants, you could grow it as an experiment, but if it is going to be part of your main crop and you have limited space, I would strongly suggest you forget about it and start a new seedling or two. It is always prudent to plant more seeds than what you think you will need, just in case of duds or other weird outcomes or failures to germinate. This way you can choose only the best and healthiest seedlings to invest your time and effort into. Other people may say "give it a go and see what happens" but they are not the ones risking 3-4 months of growing and then possibly ending up with crap buds, then advising you to "chalking it up to experience"! As I said earlier, in my (40-ish years of) experience, seedlings that start off weird, usually end up finishing weird too and are generally a waste of time. Hope this helps, Organoman.