That should be Flavanone A to Flavanone B.
Don
You wrote: “Whatever the reason, pairings of other roses with roxburghii seem to give offspring in which the traits of the other rose dominate.”
I am actually planting out a few dozen of this year seedlings:
(diploid sp hybrids) x ((diploid sp hybrids) x rox)
diploid sp hybrids are a selected group three to four crosses derived from rugosa, bracteata, foliolosa and nitida.
Contrary to your opinion globally and unexpected these seedlings are outstanding as being quite unlike mothers and very rox like.
As much as was the (diploid sp hybrids) x rox that were looking like not much modified rox.
Selfing is not a possibility as rox and rox hybrids were pollen parents.
Contrary to your opinion globally and unexpected these seedlings are outstanding as being quite unlike mothers and very rox like. As much as was the (diploid sp hybrids) x rox that were looking like not much modified rox.
Thanks for this, Pierre. So then, diploids with roxburghii show strong roxburghii characteristics. Have you crossed any tetraploid moderns with it?
Some diploids at least show strong roxburghii characteristics…
I have not crossed tetraploid moderns with rox till now.
Thanks for this very interesting and informative post. I do remember reading somewhere in rose literature that Tantau was questioned several times by collegues concerning the parentage of Floradora and Cinnabar and he always stuck to his guns.
Jim
Speaking of ‘Max Graf’ descendants and inheritance of doubleness, you may want to take a look at this:
Link: paulbarden.blogspot.com/2009/08/inheriting-doubleness.html
DNA testing is always able to provide a definitive answer if enough DNA is sequenced. Completely sequencing a plant’s DNA is still prohibitively expensive. It wasn’t even possible when Dr. Byrne tested Basye’s Purple. With the technology that was available at the time, he must have only tested a handful of markers out of the billions of base pairs in the rose genome. Those few markers could easily miss the DNA contribution of a parent.
I certainly respect Tantau and agree that he knew what he was doing, but did he know about the possibility of apomixis in roses? The earliest evidence of apomixis in roses that I know of was published decades after Tantau died.
And there is the issue of Tantau’s seedlings’ ploidy. One would expect that most of the seedlings from the cross Baby Chateau X R. roxburghii would be triploid, while all of Tantau’s seedlings are tetraploid.
Tantau’s roxburghii x Baby Chateau introduced vars if showing little rox were outstanding enough to have at least some new features and ample progeny.
That all of Tantau’s selected seedlings are tetraploid is the key in my opinion.
If they got 3n from Baby Chateau and 1n from roxburghii I do not think apomixy is obviously involved. That modern roses may have some 3n pollen has been found. A 3n modern + 1n species is equivalent to a ready made first backcross to modern. Eventually with full fertility…
I have raised a lot of triploid from species x moderns. They range from modified species to close to modern. No wonder some are hidding most species contribution when backcrossed to moderns.
Why would Tantau’s selected seedlings be more likely to be tetraploid than triploid? Triploids are often superior to tetraploids.
3n ovules are rare in a tetraploid mother. That multiple 3n ovules would be produced and fertilized by roxburghii pollen and produce viable seedlings seems unlikely. That all of Tantau’s selected seedlings would be tetraploid is very unlikely.
Also, when Tantau crossed his ‘roxburghii’ seedlings with each other, the resulting seedlings had no roxburghii characteristics. See for example,
Tantau’s Delight - Cinnabar X Kathe Duvigneau
Cinnabar Improved - (Cinnabar X Kathe Duvigneau) X Cinnabar
If there were hidden roxburghii recessives in the seedlings, one would expect some of them to come out in the F2 hybrids.
None of Tantau’s Baby Chateau X R. roxburghii seedlings have the ploidy that would be most likely from this cross. The seedlings don’t have any roxburghii charactersitics. The F2 hybrids don’t have any roxburghii characteristics. I think that it would be wiser to wait for DNA tests to decide the issue than to assume that the seedlings have roxburghii DNA.
“Triploids are often superior to tetraploids.”
How so? I’ve seen this sentiment implied by various authors, but I’m not sure why, or in what way triploids are superior. Please explain 
Paul
You may remember I like friendly controverse…
“Why would Tantau’s selected seedlings be more likely to be tetraploid than triploid?”
Just as being more marketable. I.e. recurent, not too large and with modern flowers the triploids were not.
Most roxburghii hybrids I raised are quite large growing.
“3n ovules are rare in a tetraploid mother”
I do not know. Particularly about Baby Chateau we are dealing with.
“Also, when Tantau crossed his ‘roxburghii’ seedlings with each other, the resulting seedlings had no roxburghii characteristics.”
Why should Tantau have to select these seedlings differently?
And which rox characteristic do you think he should have selected for when he had a new cleaner scarlet orange color that then was so much looked after.
Were it easy to find marketable tetraploid recessives.
I think that it would be wiser to wait for DNA tests to decide the issue than to presume that the seedlings are from apomixy.
Particularly as Baby Chateau then was crossed by all roses breeders as it was known for giving new (pelargonidin) colors.
Why would only one breeder get Baby chateau apomixied seedlings from it if roxburghii did not interfere?
Notable is that these Tantau’s vars were recognised as outstanding.
Why should Tantau have to select these seedlings
differently? And which rox characteristic do you
think he should have selected for when he had a new
cleaner scarlet orange color that then was so much
looked after.
Why would the color be incompatible with roxburghii characteristics like plant architecture, hip shape, leaf form, prickle shape and placement, etc.? The fact that Tantau selected for a particular color shouldn’t preclude other roxburghii characteristics from appearing in the F2 hybrids.
And why aren’t there any roxburghii characteristics in the first generation seedlings? Surely roxburghii’s genes aren’t all recessive. There are first generation roxburghii hybrids like Coryana and Micrugosa that have strong roxburghii characteristics, so clearly some of roxburghii’s genes are dominant.
Why would only one breeder get Baby chateau apomixied
seedlings from it if roxburghii did not interfere?"
Apomixis can be triggered when incompatible pollen is placed on a mother plant. Other crosses with Baby Chateau used pollen that was more compatible than roxburghii pollen.
I think that it would be wiser to wait for DNA tests
to decide the issue than to presume that the seedlings
are from apomixy.
I’m not presuming that Tantau’s seedlings are the result of apomixis. I’m saying that DNA tests should be done to verify their parentage because nothing about the seedlings suggests that they have any roxburghii DNA. Apomixis is one reasonable explanation for Tantau’s seedlings, but other explanations are also possible.
Among my first experiments I put mixed modern tetraploid pollens on bracteata and with beginner luck got ample germination (never achieved anymore) and a lot of seedlings that as a rule didn’t show any bracteata characteristics.
Expressed were other features those breeding bracteata derivatives know such as improved strength and health with some unexpected bright colors like orange or yellow.
Bracteata seeds and hips are very different and confusion is impossible.
Most were sterile triploids.
One of these seedlings was entered in four international roses trials hiding pedigree (Belgium, Germany, England and France). A lot of the best european specialists and breeders examined it without having the slightest hint about its mother.
Downpoint was that most were too large plants.
Large untamed shrubs with long diverging shoots.
So if there were there some tamed seedlings with outstanding color they would have been instant selections even if sterile…
If easy recovering species recessive features among our seedlings would be quite frequent as all roses are from species often the same. In my opinion it is a very rare event and one that will never result in selectable plants.
I’m saying that DNA tests should be done to verify their parentage because nothing about the seedlings suggests that they have any roxburghii DNA.
OP seedlings of Baby Chateau would be the same as apomictics, would they not? If one of our European members were to send me some seeds from Sangerhausen or l’Hay I could germinate them in-vitro and spread seedlings around to our US members for study and breeding.
RE; R. bracteata.
My first cross using R. bracteata itself was done a few weeks ago, using the diploid breeder ‘Magic Wand’ by Moore. The idea was to marry diploid to diploid, possibly avoiding the ploidy confusion that continues to express itself in the descendants of ‘Muriel’. (‘Muriel’ is a tetraploid that is highly fertile as a pollen parent, but evidence suggests that it produces a mix of haploid and diploid pollen) Much to my surprise and pleasure, the ‘Magic Wand’ pollen has taken and there are about a dozen fat hips forming. The seedlings, if I get any, will likely be nightmarishly wild plants that will threaten to eat up my facility in a short time, but who knows; ‘Magic Wand’ is a powerful breeder that has a strong inclination to dwarf anything it is put on. Fertility in the offspring is the main goal at this point…
Paul
(apologies for hijacking the topic)
OP seedlings of Baby Chateau would be the same as apomictics, would they not?
OP seedlings might not be from Baby Chateau pollen. And apomictics would be much more homozygous than selfs.
That’s very interesting about R. bracteata X Magic Wand, Paul. I tried a number of crosses with diploid pollens on R. bracteata and R. clinophylla this year but none of them look like they are going to take. It looks like I might get some hips from R. bracteata and R. clinophylla pollen on several diploid seed parents, but the crosses were just done 3-6 weeks ago, and it is too soon to know for certain.
Maybe roses closer to the asian species match best for f1 bracteata creations.
Jim,
I also pollinated my R. clinophylla with ‘Magic Wand’ and got seed hips forming on it as well.