could it be worthwhile to graft a plant with a good root-stock?
Many of the unique characteristics of each specific tobacco variety (of which there are many thousands of named varieties) are determined by the growth and metabolic activities of its root system. What is a "good" root-stock? Unlike fruit trees, from which we harvest the fruit, tobacco is grown solely for its foliage. All of its alkaloids are produced in its roots.
I'm sure it would be an interesting laboratory experiment (demanding a considerable number of plants, control plants, and detailed chemical analysis, in order to make any sense of it), I can't imagine a practical application of grafting for a home tobacco grower. In addition, as
@Knucklehead pointed out, "secondary" growth from a root system or stalk tends to be of lower quality than its primary growth.
Although in the sub-tropics, tobacco is a perennial plant, even sub-tropical tobacco growers start new plants from seed each year, and have done so for at least hundreds of years.
Grafting tomato onto a tobacco root-stock has been demonstrated in research studies. They are closely related. You get (in the words of the cartoon character, Bart Simpson) "tomacco".
Bob
