I thought that this was brought up before. Maybe it was at TOP.
Not and expert, but from my Cypriot experience. There was only one citrus tree that would grow from a root. I cannot remember which one it was.
All other varieties were grafted onto this one type of root stock.
Another but! Sometimes these grafts produced hybrids, such as sweet lemon/oranges, which maybe what the ExA's have in Bots.
A neighbour of mine has a sweet lemon tree, the fruit were gorgeous. But useless for brandy sours.
Just my two pennyworth.