Will two varieties of tobacco hybridize (rustica and tabacum) ?

Hello permies,

I will be planting three varieties of tobacco this year, and since I'd like at some point to harvest their seeds I'd like to know if I'll have to do anything special to keep the varieties pure..

I have 3 varieties, two of which are nicotiana rustica (Ancient and Punche Mexicano) and one which is nicotiana tabacum (Hyang cho).

Obviously, the two nicotiana rustica will hybdridize between them if allowed to, but can they hybridize with the nicotiana tabacum ?

Thanks.