genotype of sports as parents

I had been wondering if there is any merit in using a sport in a cross – when the sport has more admirable qualities than its own “parent” from which it sported – instead of using the sport’s “parent” in the cross. My impression is that while a sport may express a different phenotype, it may not differ in terms of the genes it can pass on as a parent. The frequency of reversions might indicate that in many cases, the difference in genotype between a plant and its sport is essentially non-existant.

Specifically; let’s say for instance I’m wanting fuller flowers in offspring; would there be any benefit in using Awakening as a parent over New Dawn, when generally the more double blooms have less pollen and are more difficult to breed with? Or is there really any difference in what N.D. and its sport, A., can offer to offspring?



Some pass on. Some do not. For example, Cl. Tropicana passes on the climbing trait. In an older ARS book, I remember a large article about Cl. sports and inheritance. The large array they used summed up to about 50% climbing seedlings.

I think it depends on what type of sport it is. For instance many climbing sports are somatic mutations and do not affect genotype.

I read “someplace” (forgot the source) that Climbing Crimson Glory, a sport, passed on its climbing traits.

Rose tissues are formed in three apical layers, L1, L2, and L3. Seeds and pollen are produced only by L2, so a mutation in L2 could be passed to the offspring. A mutation in L1 or L3 could changed the phenotype of the plant, but the mutation would not normally be passed to the offspring.

While googling for a good description of this, I ran across the the paper linked to below. According to it, L1 or L3 tissue can sometimes get into L2 tissue, and that could provide a path for a mutation from L1 or L3 to get into offspring.


As they grow larger and being more away of soil usually are healthier, I have used Cl sports as female parents. Got ample seed production but a lot of unwanted climber seedlings.

Often a 3/4 ratio. A nuisance when you do not hybridize for climbers.

I do not any more.

That’s interesting Pierre. I always assumed climbing sports of hybrid teas (for instance Cl. Peace) would produce seedlings similar in habit to the bush form?

Do the seedling climbers produce stiff canes like the parent?

Robert, you wrote: “I always assumed climbing sports of hybrid teas (for instance Cl. Peace) would produce seedlings similar in habit to the bush form?”

No Cl sport from a dozen HT & Fl I used did it.

But only one that does not climb and is clearly a reversion to bush.

Cl habit is readily transmitted and stiff canes are a rule.

In my experience canes stiffness is strongly influenced by the seed bearing parent.

Thanks Pierre. I’ve never used climbing forms as I have limited space. I’m glad I did not.

Thank you all.

And Jim, I suppose that is why a chimeric trait such as variagated foliage is not typically inherited? As I understand it, the variagation is typically a function of some apical layers not producing chlorophyl.(?)

I believe concerning variagation, the general rule is that the variagated plant has to be the seed parent if you are crossing variagated with non. I think that is what they do with hostas (again distant memories).

There has been so many good points presented. I think it’s really hard to answer your question Philip because so little is known about rose genes and the source of changes in sports can be due to various genes or expression mechanisms that we don’t have the resources or time to study for each sport. The idea of climbing sports of hybrid teas is interesting and that they are transmitted to offspring (consistant with a dominant allele(s) ). I wrote about it in a previous newsletter article that I suspect the mutation is due to a regain of function (or at least partial regain of fuction) of at least one allele of the repeat/non-repeat bloom gene which may be a gibberellic acid gene according to Roberts et al. (1999 I think their paper came out). The climbing version acts partly like a one time bloomer in that it puts more energy into long canes instead of quickly terminating into flower buds as consistently after so many leaves.

Great point about the meristem layers Jim. In my chromosome doubling work I carefully tried to assess ploidy in each layer in order to identify plants doubled in Layer II because, like you said so well, that is the layer giving rise to gametes.

For doubleness of bloom, I think it may be useful to use the more double version. There are minor genes that act additively that contribute to final petal number in the presence of the dominant allele at the major gene that governs if the rose will be single or double (need a dominant allele at this gene for double flowers to be expressed). Perhaps the more double rose may be double due to mutations leadign to additional effectiveness of an allele already there or additional allele copies of those that contribute to greater numbers of stamens being converted to petals (petaloids), or may be due to changes leading to those alleles which contribute to less petals being somewhat or fully silenced. Such changes may be DNA sequence changes and transmitted to offspring and may skew the progeny to more individuals with overall more or less petals.

Just some quick thoughts that come to mind.



Robert, Eden 88, Autumn Sunlight and Royal Gold are all from climbing sports of floribundas. The former two are flexible. Of the 3, Royal Gold is the only with the sport as a female parent. In contrast, it is the only one being crossed to only a HT. Similarly, Orange Velvet follows the identical pattern of Royal Gold.

Personally I do not think there is anything wrong with stiff climbers like Orange Velvet. It is, in fact, one of two (Shadow Dancer being the other)climbers that has stayed with me for more than 8 years. I like it because it maximizes vertical space to it’s best. It blooms a ton despite being tall and rigid.

But if one does not like that I suppose trying a climbing sport as a male parent may be a better angle.

Very interesting question.

I had a colleague working on mechanisms of sporting in potazalea (Rhododendron simsii).

Sporting is still a phenomenon with an unclear background. Mostly it is agreed that a sport is not a genetic mutation as it can not be revealed by DNA sequence changes. For some characteristics it is thought that transposons (jumping genes) are involved (these altered phenotypes can be inhereted) for other characteristics it is thought that DNA methylation is involved (this will influence gene expression).

But what about ploidy mutations?

In the research on potazalea mentioned above, we found tetraploid petal margins (the center of the flower is diploid) as a result of sporting in diploid plants.

We still have no explanation for that phenomenon.

DE SCHEPPER S., LEUS L., MERTENS M., DEBERGH P., VAN BOCKSTAELE E. & DE LOOSE M. 2001. Somatic polyploidy and its consequences for flower coloration and flower morphology in azalea. Plant Cell Reports 20: 583-590.

Leen, here is a question that is probably way out there but is it possible to clone plant material from the tetraploid petal margins?

Rob,I do not believe it is possible to clone material from fruiting organs. Petals, of course, are included.

Yes, it was possible to regenerate plants from the tetraploid petal margins by use of in vitro techniques.

For example when plants were regenerated from a white margin (pink center) then the regenerants were completely tetraploid and had white flowers.


Thank you for the response. I don’t know anything about breeding in Rhododendron simsii (or others) but is a tetraploid clone derived from the white margin desireable for further breeding?