"Clonal breakdown" is an interesting term, and I do know that continued propagation of many plants can lead to decline in vigor, etc., but what does the term actually refer to? If it is actually a change in the genetics of the plant, then no amount of tissue culturing and "cleaning up" of the clone is going to change the genetics back to the original. Does anyone know what the theory is re what is actually taking place if, in fact, it is not removing virus. For that matter if the virus has been incorporated into the genes (as often happens), then how do they clean that up by tissue culture? Or, are the answers to these questions to technical for this list? Ernie O'Byrne Eugene, Oregon USA > Sender Allowed > > Way back in the 60's, the lily hybrid Enchantment, introduced by Jan de > Graaff's Oregon Bulb Farms, began to loose the size of flowers and the > bud count. <snip> This was > thought to be a clonal breakdown, not an unusual occurrence and I think > this was a correct diagnosis. > <snip> > > This might be of interest, the point being decline of a plant is not > always due to a virus, but continued propagation by vegetative means can > also cause problems. Cheers, John E. Bryan > >