I think the issue is that hybrids can always be made, but never unmade, so
as it is in the absence of new collections everything will end up as
hybrids. Also, if hybrids are backcrossed, you may end up with hybrids
that get mistakenly passed off as the pure strain and then the pure strain
will become quickly compromised because of the error.
They are the thin end of the wedge.
Doug
Doug Karpa-Wilson
1821 S. Maxwell St.
Bloomington, IN 47401