Hi Simon,
I love your photo of ‘Euphrates’. When I first started getting into roses, I saw a similar photo of ‘Euphrates’ in a rose book. I thought, “now that’s a rose that I would like to breed with”. I new nothing of the “Hulthemias” or “persicas” at the time. I was later disappointed after more research to find that it was “infertile” (I know now that there is some question about that statement). I guess that I was “hooked” on the Hulthemias before I even knew what they were.
Regarding the dominance question. I agree that it must be dominant, however, when combined in tetraploids with 3 other chromosomes lacking the blotch, the blotch seems to always be smaller, It is only in combining these 1/4 with each other that there are a few seedlings having larger blotches (2/4). It seems like just as mathematically speaking that the Hulthemia diploids vs. tetraploids appear similarly with respect to blotch when 1/2 = 2/4.
I am not sure that simply going to 2/2 or 4/4 will increase the blotch size or intensity. If one compares ‘Euphrates’ blotch size and intensity, I think that you are already at “maximum”. Especially as compared to Hulthemia persica specimens. It seems that the actual species blotch size covers no more than 1/4 to 1/3 of the length of the petal, beginning at the petal apex.
The next step to increasing the blotch size, I think, is reliant on small variations of incremental increase in blotch size seen in a population of seedlings = selective breeding.
Below is a link to a seedling photo posted on my facebook that has a blotch size and intensity comparable to 'Euphrates. I suspect that through selective breeding it will be possible to get larger blotches.
Jim Sproul
Link: www.facebook.com/photo.php?pid=678305&l=a2b0ac958d&id=1154482228
Hi Jim!
Your M40-1 is a very nice plant, it always makes so much fun to view one after another of your plants.
I would say - only according to that foto - this one is one of the best I have seen.
I love strong contrasts. …
Grx!
Arno
PS:
Your Idea, Simon, of breeding with polyanthas / lambertianas etc. is really what I would call a good perspective.
I did lots of such crossings this year, the seeds of polyanthas also germinate easily.
Only hint: the colours might fade more quickly … .
But as a special perspective - one possible line to go - its a good idea for sure I think.
That’s a really beaitiful seedling Jim… it shows what I had ni my mind’s eye when thinking ‘Trier’ x ‘Euphrates’. If I get even half that nice I’ll be stoked!
The only thing, except from equivalence, about the 1/2 and 2/4 blotch, to me, is the polygene factors. It has to come down to selective breeding as you say but even if we had 4/4 blotched (or 2/2 blotched) some are going to be bigger and better than others and my take on this is that whilst the blotch factor itself might be dominant there are many other genes influecing the size and intensity of it that I loosely call modifying genes. So when looking at diploids you have far fewer of these polygenes affecting the blotch than you do with a tet. A lot of polygenes seem to work in a cummulative manner so with twice as many polygenes you have twice as much work to refine it… maybe that’s the wrong way to look at it but I kind of think about polygenes like a + or a - and the more + (or -) the greater will be the effect on the expression and by selective breeding you are ‘collecting’ or ‘discarding’ the polygenes to give the effect you want. I guess this is irrelevant if you want to make the leap into large flowered tetraploids 
Is the hulthemia blotch at all related to the yellow blotch of various sizes that is sometimes present in modern hybrid roses? I have a cross between a magenta Virginiana hybrid & a yellow mini that is red with a distinct yellow blotch. I’m wondering if a similar mechanism is at play.
I dont know but I have noticed that the red blotch tends to be rustic or purplish in tone.
Hi Simon,
I do see what you are saying. I think that both strategies are equally worthwhile, I am just limited by having few options for repeat blooming diploids. Tetraploids abound.
Hi Lydia,
The yellow “eye” in modern roses is a totally different effect and is almost the opposite of the Hulthemia blotch. It seems that roses with yellow or white centers tend to reduce the Hulthemia blotch - almost like “washing” it away. The yellow or white center areas are produced by a lack of the overlying color, with just the base petal color showing through. In contrast, the blotch is produced by an over lying color on top of the base color.
Jim Sproul
I think this question (about patterns on rose petals in general)really needs some careful thought and study. To start with, maybe we all need to look at the layers of cells and find out where the pigment is located. Jim says the blotch is an overlay of color. The yellow base may be suppression of overlying color. Purple may be laying the red blotch over yellow? Crimson roses like Crimson Glory and Mr Lincoln, seem to have yellow at the petal base, (and maybe underlying the whole red part to brighten it?). What about the “hand-painted” series.
And of course there are lots of examples of picotee patterns with just hints of color at the tips of petals. Are those just an extreme case of the central suppression gone crazy? The picotee pattern is common to many flowers, so it has a common origin.
So, for that matter, is the central ring of contrasting color. In daisies and such, yellow is a strong UV absorber that looks brilliant to bees, as someone suggested earlier, a real advantage in deserts where floral resources are scattered. Tulips, from Turkey, also show this a lot.
Can we think of how a petal develops and consider the gene actions needed to turn on and off the pigment production in different parts? Make a list of all the various instances, and how they recombine in hybrid offspring.
For instance I think all bicolors descend from Austrian Copper. Can anyone give a definitive counter-example? Was there a bicolor HP or HT before 1900? (I mean leaf upper and lower surfaces with contrasting color or lack of it).
You could go on thinking patterns for quite a while, but there must be a common set of controls.
Thanks guys. Good to know.
The older crimson HTs are descendants of the pernetianas, hence the yellow area where the petals attach to the hip. Its too bad that there is a gap between the known lineages between them and the pernetianas and hybrid perpetual (and other random red china hybrid descendants). A lot of them were simply unrecorded. Even Crimson Glory is not fully shown, since we have no clue what the lineage of W.E. Chaplin is. Liberty, which a lot of reds descended from, is also only half-known. I am guessing that roses like Independance and Fashion received part of the visually orange-toning not only from the pelargonin of the floribundas they came from but also from the pernetiana influence within Crimson Glory.
Picotee in roses is a little muddled. Some roses have a true picotee and some are just a really vivid point of blending. The difference is usually easy to tell if you look at the reverse of the petals, especially after they hve aged. The true picotee types will have the darker band on the petal reversed etched in still. Examples of this are Playboy, Cherry Meidiland, Betty Boop, among some others. I have noticed that a huge portion of picotee types run in lineages. The Karl Herbt lineage is pretty dense in picotee types. However, other Peace tribes are void of it. I am guessing that it has something to do with the Queen Alexandra Rose, which is one of the first true, completely bicolor HTs. This rose is doubled up in the lineage of Picadilly.
I think picotees and Rosa foetida bicolor/other bicolors have a link but I am unsure as to how it is happening.
I am also unsure how these colors and patterns affect the eye zones, but it is interesting that the red on Rosa foetida bicolor has a similar unuusal, rustic tone as some of the eyes in the hulths. The one thing we do know is that this rustic tone can be replaced with other types of red pigments with further breeding.
Here is an interesting example of a recent rose from Meidiland that is almost 100% bred from multiple hybrids still pretty close to the pernetiana connection. Check out the coloration compared to most modern bicolors and blends:
A hybrid tea with unknwon parentage of similar color is called Bronze Sunset. The rustic coloring isnt evident in the photos, sadly, but I have grown this rose and am full aware of them. I am guessing it is descendant of Arizona, which is pretty much all pernetiana.
Link: www.helpmefind.com/rose/l.php?l=21.146166
Larry wrote:
“I think all bicolors descend from Austrian Copper. Can anyone give a definitive counter-example?”
Sorry
Mutabilis is a bicolor with darker outer side of petals.
The reverse that is lighter outer side can be seen in some rugosa seedlings/vars.
Both bicolor features are easily transmited to progenies.
Thanks, Pierre. I never considered mutabilis in that category though I grew it for a couple decades. I was more busy watching the color change on the front face of petals.
Maybe I should have said, all bicolor HT and floribundas? Would that be accurate?
Any evidence that rugosa genes are behind any tetraploid bicolor?
Maybe bicolor is more common that I reckoned, but only is noticed when there are lots of petals, and some time is spent in the partially opened state.
Really, my point is that we can identify relatively few basic patterns of petal color, and the a whole lot of variants of intensity, or fraction of the petal expressing a pattern.
I’m thinking in terms of how a very few genes determine the order of sepals, petals, stamens, stigmas. And how easy it is to switch a stamen to a petaloid or true petal. Similarly color patterns ought to be controlled by a few major genes.
The bicolor is one that goes underground easily and pops out later unexpectedly. For instance a couple of von Abrams’s roses were bicolors, out of pedigrees where the trait was hidden for some generations. But you can see where it came from. And Paul Barden’s Incantation is very like Austrian Copper or Condesa de Sastago, in some ways regarding patterning.
Anyway, it might be useful to try to catalog the major classes of variation and see if we can make sense of the heritability. No one but a breeder looking at lots of offspring is likely to be able to figure this out.
Larry it would certainly help some times if we had some chart with percentages to look at. I know irises, daylilies, African Violets and others they have figured out these things. The major problem I see with this is most plants that have such charts are either inbreed or do not suffer as much to inbreeding depression. I think you would have to inbreed a lot of roses to get such a chart. After that is done it would be hard to relate to hybrids that are out there because of the background of most are diverse at least when it comes to color. Perhaps if we got a group of people together that was willing to devote some of their work to making control crosses; many of these selfs; and then we pooled all our results together we can begin to make sense of this. We would have to grow a lot of poor seedlings and let them at least make it probably to the second bloom. Also it would be a lot easier to work with diploid rather than tetraploids. But at the same time genes can change the way they are expressed when you go up in ploidy.
I do think some of the genetics are known. But I do not know them myself. My main philosophy has been try not to use to many pink roses, try to cross different colors together without worrying what color they are mainly basing plant selection on other qualities (then usually changing at least one parent so they are not both pink!!!) , and hope for the best.
Anyone else got any thoughts? Very interesting subject by the way!!
A darker reverse would be a reverse bicolor rather than a true reverse. Theyre different and seem to express differently when crossed with self-colors. Duet, Belle Epoque, Remember Me, About Face, Blueberry Hill, Pretty Lady. I cant tell from photos, but species like rosa moyesii might be reverse bicolor. This petal pattern seems to descend heavily from roses that are orange-red self-colors or red self-colors high in peonin (as opposed to cyanin).
Hi!
I added the fotos of the petal site of the blotch and the reverse for Persian Mystery.
Grx!
Arno
Link: www.helpmefind.com/rose/l.php?l=2.61025.0&tab=36
I forgot to add that crossing a reverse bicolor with a reverse seems to usually end up in blends. On another note, crossing Solitaire, which is not quite a true picotee, with non-yellow selfs and blends usually ends up in true bicolors. Most roses seem to have dominant color pattern traits but some seem to surpsie you. Moon within Tidal Waves has been breeding every color and pattern common out there except the ones I want =/ I even got bright coral pink from it. Oi vey 
I did that and also got blends.