The blog articles (parts I and II) are a fun read, and I recommend them as a casual, layman's survey.
The author leans heavily on the popular book by Sherman from 1970, a book loaded with inaccuracies and outright misconceptions. I doubt that Sherman ever saw a tobacco plant actually growing. He blithely states that (fill in the blank) variety of tobacco can be grown nowhere else in the world. [Members of this forum know better.] There is also the old saw that the same varietal seed produces different varieties of tobacco, based on the soil and weather condition of where it is grown.
[Milton M. Sherman:
All About Tobacco, Sherman National Corp, New York (1970).
http://tobaccodocuments.org/nysa_ti_s1/TI56720085.html#images
is the primary source of this myth.]
As to origins of Oriental tobaccos, I would guess that a small number of genetic varieties of seed (likely less than a half-dozen varieties) were originally carried to the Ottoman Empire 500 years ago, and that the wide differentiation we now see resulted from grower selections and accidental crossing. Instanbulin's various threads on Oriental tobacco varieties, while less prosaic, are the real deal.
The blog articles' comment on the economics of small-batch varietals highlights the advantage each of us has as home growers, in our being able to test and select specific varietals for their preferred nuances. We are lucky folks.
Bob