".......Varieties of fruiting cherries are grafted, meaning that they are
not/cannot be reproduced by seed. ........."

The reason that they are grafted is because this way you can guarantee that
every plant is true to type and is ready to crop much quicker, also by
selecting the rootstock you can decide on the height and vigour of the
trees, where as if you grow from seed then you have no control, the plants
can be like either of the parent or grand parent trees or a combination of
these.
This is the way to get new varieties, but the vast majority wont be anything
special.

--
David Hill
Abacus nurseries
www.abacus-nurseries.co.uk