Subtle Sports & fragrant Old Blush

I have often thought about what actually is happening when sports occur in our roses. I am in no way a genetics expert, but it seems to me that there are very subtle mutations, subtle mutations, and then not so subtle mutations.

For instance, I am now the proud owner of a very fragrant specimen of Old Blush. That’s right - very fragrant (at least for a short while just as the bloom opens up). I stumbled across it while perusing the spring offerings at Teas Nursery in Houston. There were a dozen or so, sitting in the antique section, blooming away, and the fragrance instantly drew me to them. I sniffed the rose, and commented to my wife that “I might need one of these, I just wish I new what it was”, to which she smugly replied “its Old Blush baby, it says so right here on the sign”, I was floored.

I’ve got Old Blush, and have seen many specimens of it throughout my life, and have NEVER detected more than a very slight fragrance. Yet, this rose is almost without a doubt Old Blush. It is right next to my original, and looks, grows, and behaves just like the original, with the exception of the fragrance.

So what do I have? I suppose it could be an almost identical “selfed” of the original, or more likely, one of the two is a sport. I think I am witnessing a gene (or set of genes) that have been turned on or off due to a minor mutation.

Similarly, I’ve had specimens of the same plant from different nurseries that exhibited slightly different characteristics. Could these too be the result of minor mutations of what I would call secondary and tertiary genes - genes that modify the expression of other genes, or genes that modify the expression of genes that modify the expression…

For example, take Carefree Beauty and Katy Road Pink. Living in Katy, I at one time grew both to see if they were the same (KRP is considered to be a “found” rose by some). In my humble opinion, Carefree Beauty is slightly superior in overall health, habit, and bloom. I now believe that Katy Road Pink is a slightly inferior mutation of the original (although I suppose you can never rule out the possibility that it is a slightly inferior selfed of the original).

I ramble too much. My points are:

When can we expect sports to transmit their variance to offspring?

Will the very subtle sports transmit their benefits?

Do ya’ll have other instances of what could be minor mutations (and more importantly, improvements) that you are aware of?

Baxter

Others on this forum should be able to answer this question better than I, but I’ll put a stab at it. Plants such as roses, have their cells in I believe 3 layers (usually labeled as L1, L2, and L3), I cannot remember specifically where the sex organs are located but I’m pretty sure they are generated out of L1 or L2. If the sport occurs from a different layer (i.e. L3 (or outermost) layer, the sport may be stable but not pass its characteristics onto its progency. So it doesn’t matter if the sport is dramatic or subtle, but where its located. Also some sports are ‘chimeric’ where they occur through each layer, but not necessarily throught the whole cross section of plant (imagine a wedge of genetic variation on a cross section of plant stem).

I think I remember that some sports can be made to cross all layers by forcing a plant to generate tertiary buds (a case where all active axil buds are gone and the plant must create new buds from the side of the stem). In this case I think the Layers are all regenerated from only the outermost layer and thus the mutation is captured for genetic material.

I’ll try to check my references on this. Does anybody have any thoughts on this?

Chris Mauchline