Propagation and Mutations

Have you ever wondered why The Knock Out® Rose in your yard is perfectly identical to your neighbors? Or why the ones you see in stores all look the same?

The answer is that they are all clones.  They are exact replicates of each other which originated from a single plant like the original Knock Out® Rose – which I talked about in a previous blog, and which is still living at the house of its creator, Will Radler, more than 20 years after it was born.

In horticulture, we refer to making clones as asexual propagation, which means that we create a new plant from an existing one without the birds and the bees interfering with the process. It is in fact, quite harmless and should not bring to mind pictures of bad science fiction movies where thousands of similar looking ugly creatures with bad intentions want to conquer the world.

There are several methods of propagation, but the one most commonly used in roses today is propagation by cuttings whereby we take a piece of stem and root it in a very highly controlled environment. There are quite a few roses that are cloned the more traditional way via grafting or budding on a specific rootstock (itself a clone by the way). Tissue culture is rarely used in roses, as it is more costly and usually reserved for species that are only difficult to propagate from cuttings, or to maintain clean stock. Root cuttings are used to clone trees, but I can’t remember a single case when someone propagated roses that way commercially.

Whatever the method used, the result is a new plant that is 100% genetically similar to the one from which it came. However, once in a while during the process, a gene may get switched on or off, resulting in a mutation. Mutations are fairly common when you propagate plants on a large scale, and some very popular plants like The Pink Knock Out® Rose and The Blushing Knock Out® Rose are mutations of the original Knock Out® Rose variety, ‘Radrazz’, while The Pink Double Knock Out® Rose, ‘Radtkopink’ itself is a mutation of The Double Knock Out® Rose, ‘Radtko.’

However even if mutations turn out to be a good thing, as illustrated above, sadly most of them result in weaker plants that are not up to par with the original and thus get discarded in the selection process. In fact, in my own experience dealing with mutations, and if my memory serves me well, we have introduced probably less than 2% of all the mutations we have found or were given to us for trial.

However you should always keep your eyes open because you never know, one day while admiring the plants in your garden, you may find a rose with a branch whose flowers are a different color than the rest of the plant, and that would be the perfect example of what I just described.

VP of License and New Business Development at Star® Roses and Plants

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