Roses have been grafted for centures, yet there has never been a reported case of chimeras. I've asked about this a while back ago too. Why it doesn't do that? who knows. But this would be very conventional way of making new roses.

in cultre it can be done by having a graft in a V shape then cutting across the stem halfway up the stem and encuorageing it to shoot from the callus on the graft and therefore shooting with both varieties kevin

Nancy Steen reported that one time her 'Tricolore de Flandre' abruptly produced two sports at the same time on the same cane. One precisely matched 'Jenny Duval', the other was 'Belle de Crecy' -- she had both of these in her garden for comparison. This suggests that 'Tricolore de Flandre', of unknown ancestry, is actually a chimera.

A more definite chimera occurred from the graft union of Rosa banksiae and the Tea rose 'Devoniensis'. The plant combined the traits of the two "parents".

Many roses which have originated as sports are also chimeras. Thus, when breeding, it can make a great deal of difference whether the sport is used as seed- or pollen-parent. If the sport tissue is on the surface of the meristem, it is more likely to contribute to pollen than to ova.

Another probable chimera is the striped 'Careless Love', a sport from 'Radiance' or 'Red Radiance' (I forget which). It has stripes of red and pink, and the occasional solid colored flower.

The much-sporting Polyanthas are often chimeras of parent and sport, and so can switch back and forth -- on the same cane, and within a flower.

Flowering plants in general can support chimerism because of their layered meristems. The inner layer remains distinct (mostly) from the outer. When a cell "mutates", its descendants usually remain in the same layer of tissue, and the plant becomes a chimera.

However, root meristems do not maintain the layering. Thus, if we regenerate plants (like roses) from root cuttings, we can expose sports that have been hidden in the inner layer of the meristem, or within the wood-side of the cambium.

Karl King

Here is a link that might be useful: CybeRose

Dear Kevin,

Hi! From your original description it appears that you are describing a sectoral chimera, a section or kind of pie shaped portion of the growing point bearing a mutation (either in all three layers of the meristem or even just one) and you get a section of tissue showing a different color for instance. I notice this rather commonly in blooms where there is a petal section or section of a whole bloom with a distinct color mutation. The challenge in this situation is to propagate a new plant from the mutated part to stably maintain the new mutation as a complete plant. As Karl describes, there's different types of chimeras depending on if the mutation is in a complete layer of the meristem or not. Chimera just means that there are some genetically different cells in the growing point. Depending on how the genetically distinct portions are arranged will depend on how stable the chimera is and how it is expressed in the plant tissue because the different layers give rise to different tissues. For instance most of the petal tissue is derrived from layer II and then just the outer layer of cells typically from layer I. Depending on the layer mutated and which layer is giving rise to various tissues, the ability to observe a chimera will be influenced. For instance, a mutation for flower color in layer III that is maintained as a periclinal chimera will not be expressed as long as the layers of the meristem is intact. If someone roots a stem cutting of this branch (adventitious roots typically come from from Layer III derrived cells) and then someone takes a root cutting and stimulates an adventitious shoot, the mutation from that once chimera can be expressed since all three layers of the new meristem from the root cutting will have come from layer III cells.

Chimeras are interesting and they are common in plants. Identifying stable ones and / or isolating interesting mutations from them to make stable sports is often a challenge.

I had a rose seedling that had streaks of variegation in the foliage this past spring. It appeared to be due to a periclinal chimera where layer II of the meristem was unable to produce chlorophyll. It was somewhat unstable and not that attractive unfortunately.

The sectoral chimeras, like what you seem to have described, are generally pretty unstable. In the growing point there is a battle for one section of the chimera in a layer or layers to battle the other until one finally overtakes the whole layer(s).

As Karl described with striped blooms that's in essence a type of chimera as well because the different colored petal portions have a slightly different genetic makeup. No one has really done the genetics to conclude how gene expression is influenced, but it is generally throught to be due to transposible elements / viruses and not really differing genetics between layers of the meristem. Within layer II of the meristem sections of DNA are periodically jumping out of a color gene, allowing it to express itself. For instance, you can have an anthocyanin gene for red color with a transposible element in it blocking its expression so you see white. In petal tissue this transposible element is often stimulated to transpose (move out of the gene and insert somewhere else) allowing for the anthocyanin gene to express itself in the orginal cell and cells that divide from that cell leading to a widening streak of color.

Sincerely,
David

hi all,
i am interested in chimeras because i have one that is part mr lincon and candy stripe .it is a pity it wasnt half red and half yellow and it is known that candy stripe is some times darker than normal. the initial flower was a red and light pink striped flower. i have one mr lincon that had some candy stripe leaves and less thorns than normal and three candy stripe stems that show mostly candy stripe including the flowers except one flower had two crimson petals with the rest of the flower looking like a darker than normal candy stripe,the crimson petals fade like lincon and another shoot that looks like candy stripe but the leaves are much thicker and much more shiny. possibly the only one that might be stable is the last one but i am trying to stableise the candy stripe with two crimson petals and hopefully more crimson petals by asexual reproducion. also i will try to get a shoot from the candy stripe leaves on the mr lincon shoot. it is very interesting to read what both keking and david have wrote thanks kevin.

David,

Your are probably right about the hereditary striped roses, and possibly right about some of the sports. I have not tried to "purify" 'Careless Love', so I can't say whether the two pure colors could be maintained.

So long as we propagate by stems and buds, we are likely to perpetuate chimerical tissue -- even if "jumping genes" are involved. Root cuttings give us a better shot, but a monoclone (from a single cell) would be the best way to fix the variety.

Unfortunately, some chimeras lose their value when purified. One thornless blackberry turned out to be an ordinary thorny type with a "skin" of thornless dwarf. Neither pure variety aroused much excitement.

Karl

hi all,
sometimes when you have chimeras as with this one you can easily see the different types of wood in the stem when it is dead. as everyone has said i think it will be almost impossible to isolate a good looking different flower. i have had some much darker candy stripes where the red was about the colour of a mr lincon and the white was pink. also i took five buds from the original stem and one has only had mr lincon flowers so far but with a less thorns than usual. i hope it keeps throwing different flowers as it is very interesting.
sincerly kevin

I just posted a pic of a mutation on my Ruby Baby miniature, on the rose gallery & LisaLou directed me to this discussion. Cool, I had never seen one like this. I don't know if it is a one shot deal or if it will repeat.
Laz

Here is a link that might be useful: Ruby Baby Mutation

Below is a picture of a seedling with 2 different flowers on the same plant (no grafting involved).

http://home.neo.rr.com/kuska/aspen1page.htm

Here is a link that might be useful: seedling

Just picked this from my garden. I am confused on how this happens as it was the only 2 coloured rose on the bush ?

I have a seedling which produced pink flowers with button eyes for its first couple of years--then last year I was surprised to see pink blooms with an open center. This year the seedling has produced a dozen perfect little coral pink flowers with button eyes similar to Duchesse de Montebello or Belle Isis and one with proliferation. Yesterday, however, I noticed large red buds ready to open and this morning was astonished to see two red blooms quite similar to Conditorum.

The year this seedling germinated I had seedlings from Conditorum and Rose de Resht. I have always assumed that RdeR was the seed parent and either the Duchesse or Belle Isis the pollen parent, but now it looks as if Conditorum could have been one of the parents. Although both flowers are lovely, the overall effect is rather unpleasant. One of the red buds shows proliferation, too.

Lindsey