Ploidy of 'Floradora'?

Just wondering whether the ploidy of ‘Floradora’ is known? 0-47-19 is a diploid from wichurana x ‘Floradora’ so does that mean ‘Floradora’ is also a diploid? I have OP seedlings coming up of both 0-47-19 and ‘Floradora’ and was wondering whether they would be diploid as well??? I’m assuming the OP 0-47-19 seedlings will be diploid… but what about the OP ‘Floradora’ seedlings?

In my notes I have it as a tetraploid. I also have this quoted

“Floradora is a bit of a puzzle, with the parentage claimed to be Baby Chateau x R. roxburghii (14) but several authorities claim the pollen parent was R. multibracteata (28), a ounce flowering species.”

So how did 0-47-19 become diploid then???

Baby Chateau is tetraploid so if its R. multibracteata than that easily does it.

However if its R. roxburghii than I would say unreduced gamets is the answer. (like in the kordesii thread)

I do remember reading a lot about how different people doubt the parentage. The female parent is not in question but the male parent is very questionable. It could be the result of stray pollen of anything he had growing in the area. Since it is more refined than most species crosses I find myself wondering if the parentage is write. Which ever way it is an important rose because many roses descend from it. Anything breed from Queen Elizabeth, 57185-1 (Buck) or 0-47-19 (Moore) come from it.

Of course if you did have three sets of chromosomes coming from baby Chateau and only one coming from roxburgeii than it would only be 1/4 species anyways.

When using a species as pollen parent, things sometimes get quite screwy in ways we don’t always understand. Take ‘Basye’s Purple’ for example: a test was done to determine what species did actually go into creating it, and it was concluded that there were no genes from one of the two species reported in its parentage (I forget which one, my apologies). And yet, we know fully well that it shows characteristics of both R. foliolosa and R. rugosa. Similar hybrids can be, and have been, obtained by repeating the cross.

I have also done crosses using various species on some of my easiest breeders (often highly fertile miniatures both diploid and tetraploid and sometimes triploid. ‘Golden Angel’ would be one of the latter) When using R. sericea pollen on any other rose, the resulting seedlings all appeared to be near carbon copies of the seed parent. I believe apomixis is the mechanism playing a role in these instances. (Or possibly self pollination) I have considered the possibility that this may be the case with ‘Floradora’ also. If you were to grow a population of open pollinated seed from ‘Floradora’ I seriously doubt you would see any R. roxburghii’ characteristics show up in the seedlings. And yet, such a group of seedlings would, in theory, be 50% R. roxburghii’ genetically. If you grew 100 self-seedlings from ‘Floradora’ and saw no R. roxburghii’ traits at all, then I would be inclined to think that ‘Floradora’ arose either by selfing, or by stray pollen from elsewhere, or apomixis.

It appears we don’t know the ploidy of Baby Ch

I am guessing that Floradora is a tetraploid and that Rosa roxburghii filled in the genetic loop holes. Rosa multibracteata hybrids usually have obviously hybridity in them. I have seen Floradora and it looks like a very strange, gawky floribunda with the weirdest coral-brick red color I have ever seen, lol. It definitely doesnt even look diploid.

However, that still doesnt answer the ploidy to 0-47-19, which I know too little about to even guess. I would possibly consider Floradora maybe being unstable.

This thread just led me all over HMF looking at what Kordes and Tantau used in that era =/ Which reminds me, I wonder if Hamburg is the unknown tetraploid half of Kordesii? Anyways, side thought…

Actually… thinking about it… if BC was tetraploid and a species was used ‘Floradora’ could be one of these fertile triploids. Then it might feasibly make both 1n and 2n pollen I guess. That would explain 0-47-19 if 1n pollen fertilised one 1 1n wichurana ovule. If apomixis has occurred between BC and roxburghii then ‘Floradora’ would be diploid if BC was tetraploid because 2n ovules would be involved from the BC side of the family and nothing from roxburghii. Maybe we could send David some ‘Floradora’ material to confirm ploidy :slight_smile:

If you grew 100 self-seedlings from ‘Floradora’ and saw no R. roxburghii’ traits at all, then I would be inclined to think that ‘Floradora’ arose either by selfing, or by stray pollen from elsewhere, or apomixis.

A lack of roxburghii traits in the Floradora selfings will also support the hypothesis that the roxburghii chromosomes were eliminated and replaced by a duplicate set from Baby Chateau.

What we really need to do is reproduce Tantau’s experiment. I’ve got roxburghii which, if it ever flowers, I’ll cross with whatever I can but it would be desirable to somehow recover Baby Chateau from Průhonice. Maybe this is something RHA could help to accomplish.

But the species all our roses are more or less complex hybrids with different ploidy ancestory and with more or less disturbed meiosis.

When looked after pollen ploidy often vary a lot and some tetraploids have part haploid pollen when some diploids have part diploid pollen. Not mentionning the less balanced ploidy vars and aneuploids or higher ploidy pollen that also occur.

‘Floradora’ could be one of these fertile triploids<<<<

But Adam has indicated Floradora is reported to be tetraploid. Has this tetraploidy been verified as a fact, or is it in dispute?

There’s a Floradora at Heirlooms. I doubt they would let anyone touch it though, as it is paret of their AARS garden (they are collecting one of each variety from EVERY year possible. I’m personally inclined to believe that R. rox is its parent and that Floradora doesnt specifically have predictive qualities.

I have only today found this article (see link) that states ‘Floradora’ is tetraploid. So, again, where did 0-47-19 come from? Can a tetraploid make 1n gametes?


I am of course guessing here, but another hypothetical scenario could be Floradora offered 2x pollen (as is more usual with tetraploids), however when it came time for it to meet with the 1x wichurana egg, fusion occured and one set of floradora chromosomes was expelled, the other was maintained, and a diploid 0-47-19 may have resulted?

The article from bulbrose I believe is the place where I got that it was tetraploid in my notes from. How reliable that is I do not know?

As far as whether or not a tetraploid can make 1n gametes Simon the answer is yes, But this is not very common? If it is a weird species cross a lot of the time these wide crosses in the plant kingdom does not know what to do with all these chromosomes so it divides the number of chromosomes unevenly in a number of ways. The problem arises when it has trouble finding the matching pair to a given chromosome. But it is possible.

I have wondered sometimes if canina meoisis came about as the rose family way of solving weird chromosome matching, or if so many natural crossing of different ploidy resulting in the plants thinking that his is the normal way things are done?


The thing about the nauralized Rosa canina in my area is that theyre highly homogenous despite the fact that Rosa woodsii, Rosa nutkana, Rosa pisocarpa and Rosa gymnocarpa bloom at the exact same time frame. I have seen what appears to natural occuring hybrids of these but none of the Rosa canina look like mixed genetics despite the fact that all of these species are everywhere here in large, feral quantities. I wonder if Rosa californica (a said tetraploid) was more abundant here if there would be more matches genetically (all of the others are diploid or post-tetraploid), and thus more natually occuring interspecies hybrids of Rosa canina here. Your question seems interesting.

Jadae how much do you think the homogenous nature is due to the fact they do not cross and how much would you say it may be due to the diploid genes are out numbered?

Maybe I will have to change my hypothesis to something else of a wacked out nature? Why canina does this still boggles my mind?

“So, again, where did 0-47-19 come from? Can a tetraploid make 1n gametes?”

I can’t speak directly to that, but here’s another scenario about which we do know something: Moore’s Hybrid Bracteatas.

Read on…

R. bracteata X ‘Guinee’ = ‘Muriel’. So, that is a diploid seed parent X a tetraploid climbing Hybrid Tea, resulting in the tetraploid Hybrid Bracteata ‘Muriel’. Lets go further:

‘Sequoia Gold’ X ‘Muriel’ = ‘Out of Yesteryear’. In this case we have a tetraploid seed parent crossed with the tetraploid first generation Bracteata ‘Muriel’, resulting in the triploid ‘Out of Yesteryear’. As it happens, this particular triploid is powerfully fertile as a pollen parent and reasonably fertile as a seed parent.

Several years ago David and I did a study of the chromosome counts of a selection of seedlings derived from ‘Out of Yesteryear’ (as pollen parent), crosses involving both diploid and tetraploid seed parents. There was a distribution of results that suggested that ‘Out of Yesteryear’ was giving a fairly even split of 1N and 2N pollen. Curiously, the cross of 0-47-19 (confirmed diploid) X ‘Out of Yesteryear’ (confirmed triploid) gave not only diploid and triploid offspring, but also some tetraploid seedlings! How do you get 4X seedlings from a 2x X 3x cross?? Ahh, the things we don’t know about roses and their handling of genes. For me, it makes Ralph’s comment “the Rose will find a way” all that more insightful.

Lastly, I do have ‘Floradora’ in my garden and it is in flower right now. I will go collect pollen immediately and send samples to whoever can assess it for distribution of pollen size. (Henry?) I have one backup specimen in a pot I can get root tips from and send out for a tip squash (David?). This way we can (hopefully) settle the matter of its ploidy.


Yeah… your bracteata article was in the back of my mind when thinking about this! I don’t suppose it matters much in the end… I’m just curous :slight_smile:

Curious even :frowning:


(Sorry about the name typo earlier. Busy fingers/poor concentration syndrome). The one thing to note that you may find helpful to your questions is that when I did Rosa canina x Rosa multiflora en masse, they all had horrible vigor. They were definite climbers but very thin, spindly, mildewed and weak. All of my tetraploid crosses (modern roses) with Rosa canina had superior vigor and health.

In order to germinate into a plant that towers over vegetation here (especially since wild roses tend to love to grow at the edges of forest and ditches lol), the seedling has to have vigor in some capacity. Also, I do not know how well something like a 1+2 or 4+1, etc. would further reproduce more generations with ease. I do find it interesting, though, that Rosa californica, which is usually tetraploid, isnt readily naturalized in this part of Oregon.