1) Is it the rootstock or the scion that determines whether the tree is a dwarf? Since I'll be growing these inside, I want them to produce fruit at A)It's the scion not the root stock

2) If it is the rootstock that determines whether or not the tree is a dwarf, which rootstocks do you recommend? I've read that Turpentine is often used, but I don't know if it will result in a dwarf tree if I graft a scion onto it.

A)Any root stock is fine to graft your Carrie scion onto.(but then again I could be wrong about this,maybe some one will correct me) Turpentine is mostly use in Florida nursery because it grows wild there and is more accustom to their soil. California uses manila(poly) root stock instead.

3) It sounds like polyembryonic varieties are true to seed, whereas monoembryonic ones are not. Therefore, if I want to purchase seeds to grow a tree to use as a rootstock, I'll need to purchase seeds from a polyembryonic variety, right?

A)Polyembryonic mango grows true to the parent fruit it came from not the scion type you plan to graft onto. But if you still insist on growing a poly seed the easiest ones to find are the ataulfo mangoes. They are the small yellow kidney shape ones, which are usually found at the ethnic or specialty store. They can be called several names based on which company is marketing them ie: honey, manila, or champagne. The real manila mangoes are not the same as ataulfo.

4) I think I'd like to try using Carrie for the scion. Does this change which rootstock I should choose for grafting to result in a dwarf tree?

A)I don't think root stock matters, it's the scion that will determine what kind of mango tree you will get. The're are many more condo/dwarf type to choose from not just Carrie(ie: cogshall, ice cream, pickering,) just to name a few. Make sure you do some research about which kind you would like flavor wise since the're are so many. Pine island nursery have a good variety viewer that gives a good description of the different variety of mangoes including the dwarf, check out their site.

5) If I grow a Carrie and want to propagate it, can I plant a seed from the Carrie to get a rootstock to start with, and then graft a scion from the mature Carrie onto the rootstock to result in a dwarf Carrie?

A)Yes, you sure can graft a scion from your mature Carrie onto your Carrie grown seedling and still get a dwarf future plant because you are creating another Carrie and not a seedling plant. But if you grow out that Carrie seed to full mature tree it will no longer be a Carrie, but a Carrie seedling even if it's also a dwarf.

check out the link, it might help you more and hopefully some more season fruit nut will come by to give their advise also.

Here is a link that might be useful: pine island nursery

Thanks for the quick reply, soaht! Glad to get some clarity on this. Also enjoyed looking through some other varieties at the link you provided. Pickering might be my new top choice, or I might try both it and Carrie.

Ya try both if you have room for two. But the Carrie has an herbal off taste( according to others that have tasted it, if not picked at the right time and is more like a simi dwarf instead). Now pickering on the other hand is a true dwarf based on the pictures I've seen on this site by other people. Has excellent flavor and is very productive, so I've heard. Do a little search for dwarf mango in the search bar and many thread about dwarf mango will pop out. But in reality, almost any mango plant can be prune down to a manageable size to keep it indoors. Good luck on what ever you choose!