While we're waiting for John Bryan's response on this, I'll add this. What John Bryan called clonal breakdown might be what I think of as clonal drift. Clonally propagated material varies over time, and the amount of variation is probably proportional to the number of replications involved. To keep a clonally propagated product within the expectations of consumers, it's necessary periodically to reselect typical material on which to base future cloning. This clonal drift is not necessarily a disadvantage. Many of the tulips of the double early division are said to be somatic mutations of the tulip Murillo, which itself is a somatic mutation of a single early tulip. So where there was originally one product, there are now many, all pieces of one original seedling. Jim McKenney jimmckenney@jimmckenney.com Montgomery County, Maryland, USA, USDA zone 7 My Virtual Maryland Garden http://www.jimmckenney.com/ Webmaster Potomac Valley Chapter, NARGS Editor PVC Bulletin http://www.pvcnargs.org/ Webmaster Potomac Lily Society http://www.potomaclilysociety.org/