<>>> some varieties don't need 'a' or 'b' ever.

me too, fascinating stuff, I've taken my info from a book for Melbourne
conditions & it makes no mention of a or b varieties at all, stating that in
the Melbourne climate different varieties for x-pollination are not
necessary, mine is about 3 years old and had its first 'baby' this season,
it got to be about the size of a walnut & fell off, I was in mourning for
the day :(