Types of repeat-flowering in roses

I’m new here. I accidently stumbled upon this interesting forum when searching for the true offspring of Schneezwerg. I saw some interesting discussions on types of repeat-flowering. (English isn’t my mothers tongue, so I appologise if I make some mistakes in my grammar.)

I.e. I’ve read that China repeat isn’t the same repeat as Rugosa repeat. I remember I’ve read similar things in the past. I’ve got several questions and suggestions that some of you could shine your light upon.

I’ve had the feeling before that there is a visible/physical difference in the repeat of a “modern repeat flowering rose” (china repeat) and Rugosa roses. Also between several Moschata hybrids. Something to do with repeating on old wood several times (creating new flowering stems on old wood) and creating new flowering stems upon new wood several times. Is this correct?

There are several species roses that are repeat flowering. Could it be that all of the repeat-flowering species in the section Cinnamomeae (R. fedtschenkoana, R. multibracteata, R. rugosa and R. webbiana) have the same type of repeat-flowering? Maybe R. beggeriana (of section Hymnocarpa) also shares this type of repeat-flowering? This rose also has an incompatible type of repeat flowering (I’ve read a book of Delbard, who did some experimentation with R. beggeriana and found him ending up with non-rebloomers after a cross with a good modern repeater.

Rosa moschata seems a different type of repeat. Maybe closer to the chinese type? Some insights I’d greatly appreciate.

I’ve found some clashing info on repeat-flowering in Rosa hugonis, Rosa roxburghii and Rosa californica. I believe them to be non-repeat flowering, but HMF claims otherwise. Maybe Rosa roxburghii plena has some old china bred into it and has some repeat-flowering, but the wild single form hasn’t? Rosa hugonis is maybe mixt up with very similar repeat-flowering hybrids? Is Rosa californica repeat-flowering?

I’ve a suggestion/idea on the incompatibility of repeat-flowering when crossing a Rugosa and a modern repeat-flowering rose. So both are on different genes, that I’ve learned. And both are recessive (not dominant). So when crossing i.e. a repeater with a non-repeater you get (a = recessive gene for repeat, A dominant gene for non-repeat):
aa x AA = 100% Aa
So all non-repeaters but with the recessive gene for repeat-flowering. If you hybridize these:
Aa x Aa = 25% aa, 25% AA and 50% Aa

That is known :slight_smile: I saw several posts in this forum that refered to this. It’s basic genetics, I guess it may be a bit more complex in roses.

So with this simple model, if you hybridize a Rugosa and a modern repeat-flowering rose. You are mixing two different genes. So you would get (a = Rugosa repeat, b = China repeat):
aaBB x AAbb = 100% AaBb (non-repeates with recessive genes for both types of repeat)

To get a rose that has both types of repeat (if that is possible). You would hybridize the offspring:
AaBb x AaBb = 6.25% aabb, 6.25% AABB, 6.25% aaBB, 6.25% AAbb, 6.25% Aabb, 6,25% AaBB, 6.25% aaBb, 6.25% AABb, 50% AaBb

If the above is correctly executed (I’m not that good in simple maths) you would get 12.5% Rugosa type repeat-flowering offspring, 12.5% “modern type” repeat-flowering offspring and 6.25% offspring that has both types. Is this a correct assumption (possible math errors not taken into account)?

You would have found the greenhouses full of once-flowering, overly vigorous miniature X rugosa and rugosa x miniature seedlings at Sequoia Nursery rather interesting.

MOLECULAR GENETIC STUDIES ON CONTINUOUS-FLOWERING ROSES THAT DO NOT ORIGINATE FROM ROSA CHINENSIS

Abstract
The Continuous-Flowering (CF) behavior of modern roses is considered to
originate from a Chinese rose, Rosa chinensis. In R. chinensis, an insertion of a
copia-like retrotransposon is present in the floral repressor gene KSN, and it blocks
the maturation of transcripts of the gene and allows the rose to flower continuously.
Most modern CF roses are expected to have this mutated allele of KSN (ksncopia).
Because of this narrow genetic background of CF modern roses, we aim to discover
the CF roses that have no ksncopia allele, which will be good breeding materials for
novel CF roses. We also aim to test the possible involvement of KSN in the
regulation of CF behavior in the novel CF species, R. rugosa. By genotyping of KSN
we found that the CF species (R. rugosa) have only a wild KSN allele without the
insertion, indicating that its CF behavior has a different origin than that of R.
chinensis. Sequencing analysis did not find any obvious mutations in the KSN gene
of R. rugosa, and the seasonal expression of KSN was clearly linked with the
alternation of flowering/vegetative stages of shoot apices in R. rugosa. Thus, KSN is
involved in the control of CF behavior of R. rugosa, although it is not simply
explained by the mutation in coding region of KSN. In order to uncover the genetic
determinism of CF behavior in R. rugosa, cross hybridization and Quantitative
Trait Loci analysis of segregating population for flowering-behavior is necessary.

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Great questions! From my understanding from the work done primarily by the research group in Angers, France, this is what they found. There is a key gene called KSN or sometimes TFL (terminal flowering locus). This gene when functional and expressed actually inhibits flowering. Early in the growing season after winter it is naturally suppressed for a bit in terms of its expression and that takes away its ability to keep things vegetative and then flowers are able to form at the growing points. Soon after flower initiation, it ramps up in expression and the rest of the season flowering is suppressed in favor of vegetative growth. For most roses, it is an advantage as it takes much of the season for hips to mature as later flowers don’t typically make mature fruit. Also, growing vegetatively helps plants in summer get larger and carve out a niche and survive in nature. This dominant typical allele with a functional gene product that suppresses bloom is the wild type. In China roses selected out of the wild and perpetuated through horticulturists, there are two variations for alleles. There is the Copia form/allele (a piece of DNA inserted that is a transposon that messes up the function) and it basically leads to lack of the suppressor and continuous flowering (like it is always early spring for flower initiation). The other allele is called a null (the gene is basically missing on that chromosome). Rosa rugosa, other Cinnamomeae like R. fedsch., and R. moschata have an alelle that is basically normal and like wildtype, but there is a mutation with an A (adenine) at position 181 instead of a G from my understanding there that leads to the bit of rebloom. This leads to a different amino acid in a spot on the greater protein of the suppressor that just isn’t as strong as the wild type in suppressing bloom. There is also another allele that from the Copia allele. When that transposon is excised out there can be a little bit of DNA that remains in there from the transposon that doesn’t fully leave and return the allele back to wild type. Examples are some of the climbing versions of bush roses that repeat a little bit, but especially invest most of the summer growth in tall vegetative growth compared to the bush form to make it a climber. It seems like for the A at the 181 position allele it is not so simply dominant or recessive and may be more impacted by environmental conditions and additional minor genes for how rebloom is specifically expressed. The French group genetically analyzed a number of roses. They genotyped them for which alleles they have and characterized them for amount of rebloom. They found a bit of variation for degree of expression in hybrids that had the various kinds of modified alleles.

I have found that the Rosa laxa I used has a bit of rebloom (probably the A181 allele). Crossing it with the one time blooming R. virginiana I had gave a seedling also with consistent late summer/fall rebloom. All the other seedlings of that R. virg. with typical modern roses (copia alleles I think) gave one time bloomers. That R. virg. x R. laxa hybrid with some rebloom put on the yellow mini Lemon Fizz led to my Above and Beyond, which also has the late summer rebloom (although I suspect it has two copies of copia as well as likely the wild type allele out of R. virg and A181 out of R. laxa). Some seedlings of Above and Beyond are truly one time bloomers with modern roses (maybe got the R. virg allele?), some have stray repeat once somewhat mature (maybe A181), and a very small percentage seems to have inherited two copia alleles to be a full rebloomer. Hybrids of rugosas and polyanthas for me have acted more like the rugosa for rebloom once they matured. I think rugosas are especially unique in that I suspect they have stronger secondary alleles that impact the expression of A181 to prevent plants from blooming too early as juveniles. Perhaps in some hybrids with modern roses, etc. they suppress rebloom more and allow the A181 to act a bit more like a full wild type??? That is just a guess. Most of the time there seems to be some rebloom in copia / rugosa A181 hybrids once they get up to size.

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Hi Karel :slight_smile:

I believe you found a lot of the information already on yourself.
Here are some things I would like to add:
Rugosa and chinensis are both diploid roses. That is probably going to be the tricky thing…
Because their offspring will very likely be quite non-fertile. It is worth the trial though because there are always exceptions but it is difficult. Dr. Svedja, a famous canadian breeder did some work on this. She did not continue on this breeding line though. Her main aim was to create hardy roses that did flower continuously.
Maybe if you could find tetraploid rugosas, then it would be interesting to cross them with modern tetraploid roses.
Or you could try good tetraploid modern rose and add rugosa pollen on it. You will get a triploid. But with some luck it can give you fertile pollen for a next generation. The thing is, things will become very tricky and unpredictible from here… the offspring might be triploid (probably most of them), tetraploid (if you’re lucky) or even some weird other ploidy if something strange happens during meiosis (possible but only small change).

HelpMeFind has ‘Lemon Fluff’ listed as the seed parent for ‘Above and Beyond’. Which is correct, ‘Lemon Fizz’ or ‘Lemon Fluff’? :slight_smile:

Hi Jonathan! Good catch! :0) It is Lemon Fluff. I made a mistake in the thread. David

@David
Thank you for these insights. I’m trying to comprehend everything that was explained here and translate it a bit so I can start to understand. I’ve only had very basic genetics in school about 25 years ago. So repeat-flowering isn’t simple dominant versus recessive genes, but a complex interaction of 2-3 different genes in wich flowering is blocked in different degrees.
What strikes me is that a wild species rose (R. virginiana) can produce repeat-flowering offspring when crossed with a repeat-flowering R. laxa. This R. laxa wouldn’t be a pure wild form, as this species normally doesn’t repeat?
Schneezwerg would be a Polyantha x Rugosa cross, I long thought it to be R. rugosa x R. beggeriana. With the comments I saw that a Rugosa with a modern repeater (i.e. Polyantha) would not give repeat-flowering roses, I kind of hoped it would actually be a R. rugosa x R. beggeriana, because that would be a far more interesting hybrid from my point of view. Lambert made some very nice roses.

@Dane
I’ve heard that many crosses with multifloras (mostly diploid) also gave non-fertile offspring. I didn’t know you could extrapolate that to most diploid x diploid crosses. I’m indeed looking into crossing different roses of different ploidy with Hansa. I like it when the leaves show signs of a rugose leaf, but milder (intermediate). Also the thorns tend to be less bristly. I like a really good thorny rose, but the bristly ones a little less. I prefer a thorn skin to a sneaky tiny needle that infects. :slight_smile: I really like the work of Geschwind in that perspective. Many crosses with Rugosas and also Setigeras. Beautiful roses, not always repeat flowering, but a good basis to work from I think.

Repeat-flowering like a Rugosa also seems better for a rose in general. It is less desirable from a commercial perspective I guess, but you get a stronger rose that grows well. I’m hybridizing since 2018, so haven’t had much experience yet. I’ve had some seedlings that flower themselves to exhaustion and die. That were seedlings from the few crosses I did with only modern roses. They flower within months after they come out of the seed. That would be the CF, I guess. I have 3 left of last year that are still alive :slight_smile: Maybe if I would pot them up again (they’re outside strugling with the elements) and with some extra love they’d grow big enough to stay alive. Any tips anyone could give me on that? Better to discard these weak ones or invest some more time in them?

@Dane you’re Belgian too? :slight_smile:

I have no knowledge of this topic and will follow with some interest, but I somehow imagined that a floral suppression gene was actively “turned on” rather than “on” (i.e. suppressing flowers) being the default position. In my mind’s scenario, a continuous bloomer would have the “on” switch broken, and roses that bloom in flushes wouldn’t sustain the “on” switch (for the flower suppressing gene) expression very long, nor strongly, thus permitting another, albeit perhaps weaker, flush. To my mind, that explained differences b/w continuous and repeat bloomers.

I learned this the hard way around 2010. Rosa rugosa alba x Baby Love alone produced 9’ beasts. Very healthy … beasts lol. We evaluated them at my friend’s farm, and I dug them up and told him to put them onto the burn pile. He kept them instead and they still thrive lmao. Not only were they beasts, but also infertile both ways. I think it would have been wiser to try Pink Grootendorst x Baby Love, but I’ll take a pass. I own Lotty’s Love, and it wasnt accepting modern roses. I tried putting Persian Flame onto Purple Pavement for years, and they always aborted. I also own White Roadrunner, and I should try a yellow on it, but I think Ive seen enough rugosa for a lifetime. I think for a hardy yellow, using rugosas seems ideal, but they come with so much genetic baggage, and their root system really isn’t ideal. There are probably better options.

It is too bad Nigel Hawthorn wasnt repeat blooming. It is one of the most enchanted looking roses I have ever seen, and its only an 18" ball of a plant. Super tiny!

I like your analogy Philip! I don’t suspect the R. laxa is a hybrid in Above and Beyond is a hybrid masking a Copia or null allele of the key flowering gene. I suspect, like R. feds.) it just has the A181 allele and it is interesting that allele seems to have a bit of dominance over the wild type allele likely in the R. virginiana rose used to at least allow for some rebloom. It seems like very vigorous canes that come up from the base or off of older stems act or pretend like they are emerging in spring I suspect and maybe the gene product that suppresses flowering is low in those new vigorous stems that they seem to pretend as if they emerged in the spring when flowering would typically happen. So for this one gene (KSN/TFL) there are multiple alleles that have different abilities to make the floral suppressor at different times of the year. I think then there are also additional genes with smaller effects that together moderate or impact degree of sensitivity, etc. to the suppressor or synthesis of it due to environmental cues. For instance, some roses tracing back to that R. laxa that repeat a little flower more freely in fall and some less freely and likely they all have at least one copy of the likely A181 allele from R. laxa. It is fun to think about the impact of these key alleles or forms of this one major gene that helps explain a good amount of the variability we see, but then there are other, maybe less pronounced. genes, etc. impacting relative expression of flowering from rose to rose too.

It is too bad Nigel Hawthorn wasnt repeat blooming. It is one of the most enchanted looking roses I have ever seen, and its only an 18" ball of a plant. Super tiny!

You would have LOVED that two blocks from the Pacific in SoCal! It flowered for MONTHS and was the healthiest thing imaginable. Absolutely gorgeous!

Sadly, like so many roses, it seems to have disappeared from commerce. I recently contacted Heirloom and Rose Petals, neither have it anymore.

-Jonathan

a quick question, is RoKSN LTR dominant to RoKSN copia?

So, how do we find out if Nigel Hawthorne still exists in Brooklyn Botanical or the Cranford Rose Garden? I will email Gregg Lowery to see if it still exists in the Vintage collection. Rosarium Scoticum (Leonard Heller) is gone. He fell off Face Book and appears to have vanished. Emails to his address are returned as a bad address. It isn’t on the interactive catalog for the San Jose Heritage. That leaves my old garden listing which is an archive.

You guys have me reminiscing about Thanksgiving with extended family, when a panoply of different conversations occur across the same table. sigh

Has any sort of plant hormone been identified that is linked to the expression of KSN? (And if so, my guess is that it is initiated in or near the ovary of blooms that have formed, or are forming?)
Does the percentage of reblooming seedlings from a cross in any way vary based on whether the trait is inherited from a female or a male parent?

I’ve found an interesting study.

https://www.researchgate.net/figure/Evolution-of-the-frequency-of-the-different-RoKSN-alleles-RoKSN-WT-RoKSN-copia-and_fig2_350563993

I think was already referred to in this thread.

I’ve also brushed up my knowledge on basic genetics (thank you Wikipedia). I’ll put some links here for other people who quickly want to get some more understanding about the abracadabrabbreviations and such :stuck_out_tongue:
https://en.wikipedia.org/wiki/Dominance_(genetics)#Co-dominance

I’ve found more info on Copia and LTR on the Dutch version of this topic. Maybe not practical, but I’ll put it here anyway: Retrotransposon - Wikipedia
And this is closely related also. Endogenous retrovirusses that define a small part of species genome and give some insight into evolution and mutation: Endogenous retrovirus - Wikipedia

I had thoughts on maybe roses could have both types of CF “genes” and in my naivity thought it maybe some super-repeating rose. In this study I found this passage and now understand a bit more what David explained (Page 7, end of first paragraph).

Furthermore, we also studied the transcript
accumulation in three roses (‘Eugène Furst’, ‘Zéphérine
Drouin’, and ‘Stanwell Perpetual’) that had the RoKSNA181
and RoKSNcopia alleles. These recurrent blooming roses
presented a low RoKSN transcript accumulation, largely
weaker than in OF roses, demonstrating again that the
RoKSNA181 allele brings a low RoKSN transcript
accumulation.

So the presence of this RoKSN-A181 weakens the CF caused by RoKSN-copia (that in homozygous state does not accumulate bloom inhibition). This was an eye opener. I now understand CF a bit more than I did yesterday :slight_smile: So I’m happy to share this with you.

Please correct me if I’m completely wrong on this.

Unfortunately, I believe the authors of that study made an error in assuming that ‘Stanwell Perpetual’ contains the RoKSN-copia allele. Evidently, they determined that based on its HelpMeFind entry, which may indicate that it flowers continuously, but I’m certain that the mode of flowering and its genetic basis is not the same as that found in China-derived roses that contain RoKSN-copia.

Stefan

They used HMF as a source to determine the type of blooming. There is no reference to the presence of RoKSN-copia on HMF for Stanwell Perpetual. I’d guess they would have determined that presence themselves.

In order to study the diversity and selection of the CF
locus (RoKSN) in rose during the 19th and 20th centuries,
we genotyped a large collection of 270 rose accessions for
the presence of the copia retrotransposon. This large
collection of garden roses represented wild Asian and
European roses, old cultivated Asian and European roses
(assumed to be the ancestors of modern roses), and
modern roses (from the late 19th century to the present)
(Supplementary Table 1).

I’ve had ‘Stanwell Perpetual’ but it wasn’t thriving. Bad spot in my garden I guess. It was one of the earliest roses to flower and repeated 2-3 times in a year. But isn’t continuous flowering. Even when suffering it kept repeating (which wasn’t good, because flowering drains a lot of resources from the plant). I think Rugosa’s do not repeat flower if they suffer a lot. They’d skip a flush.