Thornless prospective parents

I appreciated coming across this article and being reminded of some of the thornless roses in commerce, but it did make me think… Why is there so little progeny from some of the better known old thornless cultivars like Lykkefund and Zephirine Drouhin?

(I used to not care that much about prickle-free roses, but after my doctor prescribed blood thinners I had, unbeknownst to me, a small scratch, and before I realized it, I looked like I had been mauled by a chipmunk.)

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Davidson’s “smooth touch” roses were heavily based upon Little Darling. A friend used to grow them as climbers up his stone walls. In Sunland, CA they weren’t healthy but they WERE “vigorous”. I would LOVE to know WHO decided Sally Holmes was “thornless”. She is NOT. While the plant isn’t “bristled” it IS prickled and they are LARGE and SHARP. I have only ever been able to raise one seedling directly from Sally Holmes, Yellow Sally, and it AIN’T thornless. 'Yellow Sally' Rose Photo I can’t begin to estimate how many pints of blood Sally demanded from me over the years I maintained the two large plants in a client’s garden. She BITES. I’m honestly surprised that article didn’t include Mme Alfred Carriere as “thornless”. Too many lists add her and she is another which demands “blood offerings”. The prickles aren’t huge but they ARE sharp and downward hooked, perfect for deeply ripping flesh. I think my client’s plant was so well grown because of my blood sacrifices. Thankfully, she was overly vigorous for the spot and provided me the pleasure of chopping her into small pieces to fill the garden waste barrel and excavating an enormous hole to insure she was GONE. You should probably investigate which if the low prickled Teas are healthy and fertile there. Adding them to some of the smoother minis should result in some fun (and smooth) results.

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Can’t answer your why, but this season l probably did about ~ 15 crosses with various rosa using Lykkefund as pollen and seed parent. Master list on this forum somewhere.

~ 50% produced seed, and seeds at 2 months at life below zero and going to be there until March. I used gnarly second parents that take my climate.

I specifically imported it to see (along thorny Helenae hybrida parent?) if l can get a hardy parent for my hybridizing goal. With reduced thorns/ prickle’s as a bonus.

Also tried to get Zeffy for same rational plus climber bonus - out. Grew it once and probably the hardest of my bourbons ( protected) at the time and speculated to be in Lykkefund.

Go for it is my attitude … but only mine … if ur in Louisiana might be wet plague-challenge.

At the time and today l still view thornless as a bonus if it comes through.

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It seems to me that there are probably a number of compounding reasons. It has never been a trait that many people demanded, so large breeders/nurseries haven’t given it that much attention, and even the more common thornless varieties are still relatively uncommon in the trade overall. Of course, for many of us in imperfect climates, there are so few “perfect” roses in existence (none, really) that have all of the other traits we could possibly want anyway, much less thornlessness; from that perspective, it seems like one more hurdle to overcome when we haven’t even cleared the others. As already mentioned, some of the thornless cultivars out there are very poor when it comes to disease resistance in many climates. Some more widely grown thornless or nearly thornless cultivars, like Zephirine Drouhin, are also pretty infertile–I wouldn’t say sterile, but it neither had enough fertility nor blackspot resistance to make me yearn to try any crosses with it. I’m sort of skeptical that ZD is in the background of Lykkefund, which has some foliage health issues here and attracts cane borers/girdlers with the best of them, but it’s at least very fertile and can produce a certain percentage of everblooming seedlings as well as some that are either prickle-free or nearly so. However, Lykkefund is rare in the U.S. (recently introduced?) and probably approaches being common only in mild parts of Scandinavia.

I’ve been considering some crosses using a seedling of Ghislaine de Feligonde (an offspring of Goldfinch) for this reason, too. GdF itself was an absolute RRD magnet here, unfortunately. I’m not sure about RRD susceptibility in Goldfinch yet because my first plant is very young, but it has also become uncommon in the trade and in gardens. Based on its offspring, both Goldfinch and its progeny do seem to be able to produce thornless or low-thorn seedlings. One you might like to consider if you haven’t already is Cole’s Settlement from ARE, with both Basye’s Blueberry and Heritage in its background; it is very fertile and germinates easily, and seems healthier than some others from Mike Shoup that I’ve tried. Although it’s not disease free here, it’s certainly not debilitating and the plant is pretty tough overall, so it seems like it could make a good contribution to the effort. The Basye’s Thornless clone of R. luciae (R. wichurana) might also be something to incorporate as a possible building block. The rachis prickles are possibly worse on that one than some others, but eliminating those in the consummate “perfect rose” might be yet another Everest to climb.

Overall, so far, I would say that the thornless or nearly thornless roses I’ve grown and either used as parents or considered as prospects usually had at least one major flaw here and would need careful mate selection, but then, that’s true for most roses.

Riku, I’m going to be very curious to find out how your Lykkefund seeds do with the “life below zero” treatment. For me, that sort of thing has never been needed and seems like it would be detrimental, but maybe your crosses with more ruggedly hardy pollen parents will somehow benefit from it!

Stefan

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Hi Stefan,

Life below zero stratifying should never be interpreted as sending wonder woman’s golden arrow call for help against the darkness, for the germination of hardy rosa seeds … l just got impaled by her arrow after continuous flops using the status quo rote method.

I am particular disciple of it after taking warm (below 49F and above 32 F) 100% stratifying flops and burying in the ground for winter … and low behold as if by divine guidance they germinated (some vs zilch) in try 2 in year 2.

Even Lillian agreed. And some Finn of success and some Big 5 used it. More economical and good enough for me … besides that, the natural non sucker seedlings in the garden l found also made me receptive to the arrow of help change testing. Darn thing burns hot when hit.

My math of percentage improvement of below 32F cold over the above 32F coolish stratifying is nearly impossible since its division by 0 - or undefined. Will see for crosses of hardier vs temperate whether anything germinates.

The past performance does not guarantee future returns … but prevented me from tossing in the towel.

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You reminded me Stefan that I noticed a thornless seedling out of Oscar Peterson this past year and it has ‘Basye’s Blueberry’ as a grandparent, so O.P. must be a carrier. The research group in Angers, France have a recent paper on the morphology of prickles, which is interesting. Morphological studies of rose prickles provide new insights - PMC

I really love the rose Sunrosa Soft Pink. It looks like it was dropped from the series unfortunately. It is thornless on its stems and leaves. It reminds me of a polyantha in its growth. The thornless polys I work with still have prickles on the leaves. I wonder if thornlessness was included in the marketing of Sunrosa Soft Pink if that could have increased sales enough to keep it going? I wish thornless roses were more popular for garden use and we had more options among them for health and other traits. Hopefully we’ll help make it possible :0).

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Its good to know about ZD, won’t waist my time in that direction.
Has anyone worked with Madame Plantier? Help me find lists it as nearly thornless.
I am waiting on my plant to get established, so I’ll look this next season at its thorniness, now that it is getting larger canes.
I was planning on it for cold hardiness, along with the look I desire, not to mention fragrance.
I figured less thorns would be a bonus, but didn’t know if this will pass on to offspring or not.
Duane

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Boursault tried making thornless roses. Made crosses with Rosa pendulina. Maybe you could check these roses. Rosa pendulina is a european alpine rose. It should therefore have some frost resistance also.

I think some musk roses of Louis Lens have very few thorns. Maybe multiflora or polyantha influence.

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R. pendulina extremely hardy. Haven’t had raging success as a seed parent. Need to try as pollen. At least ~90-95% of cane length smooth as silk. Only prickly at base or crown. Planted 2011.

In general it’s a trait that tends to be a lesser priority when you factor in health, flower, colour, vigor, etc. I’m trying to focus on it a bit but so many hurdles, just feels like making things harder for myself.

What’s available in one place isn’t in others (eg I’d love some of Basye’s but they weren’t imported to Australia when imports were easier and now even seed is basically an uphill battle because someone imported fridges with Khapra beetle and somehow it’s seed that needs to be stopped… Same with Lykkefund, just never came here). So you kind of get stuck with things that have baggage in area’s you don’t want them, eg Marie Pavie is routinely praised…it’s usually defoliated by summer here by one spot disease or another, so you have to breed your own line fixing the baggage before you can use it for the original plan which probably isn’t the most attractive prospect.

The more modern you go the more common they aren’t great seed parents is a barrier too (because a lot of the things I want to reduce prickles on aren’t great seed parents) or have some other issues (Ebb Tide decent for seed, self seedlings can be entirely prickle free, stem and leaf…but you’re going to get issues with health, vigor and just random die back). Go back a bit further and colour saturation often goes out the window…which is fine if you just want pinks and pastels but not great if you want strong colours…it always seems like a case of adding in baggage.

On R. pendulina, like R. glauca they are prickle free where you want them to be but the lower parts of stem isn’t. Can’t comment further on R. pendulina (no seedlings yet, first year only set a dozen or so hips…if what I have is indeed pendulina, it looks it but there’s some foliage fragrance to it that isn’t mentioned for the species anywhere). R. glauca hasn’t done much to reduce prickles in the first generation (if the other parent is prickly so were the seedlings).

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Thanks for the link to that paper, David! It’s really wonderful to see solid scientific work being done to uncover new information about things like prickles. More knowledge of where and how they originate within the plant could possibly lead to better strategies for generating prickle-free roses, and that’s exciting.

It’s interesting to me that in Rubus, there are certain rather well-studied and widely used sources of genetic thornlessness, and all of them seem to alter both stem and rachis prickles equally. By contrast, in roses there are few very well understood sources of heritable thornlessness, and there often seems to be a separation between the presence of stem and rachis prickles. I’m sure that it has mattered tremendously that brambles are crops that depend upon harvesting for use and enjoyment, while briars are mostly enjoyed on the plant, except as cut roses.

Stefan

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Stefan, the point you make about Rubus species is interesting, but I fear that in the Rosa genus the issue is much more difficult to understand, not only because it hasn’t been studied as much. In my opinion, the main issue is that our garden roses are very complex hybrids, everyone of which may have different genetic codifications for thornlessness, whereas Rubus is mostly coltivated as pure species (mostly R. idaeus and R. ulmifolius). To this, we must add the complications brought by poliploidy in some Rosa species and most of the commercial hybrids.
As we consider single Rosa species, there are quite a few examples of thornless strains; both multiflora and wichuraiana have a thornless strain, and then there is R. canina inermis, sometimes (seldom) still in use here in Europe as a rootstock, widely replaced by Laxa, a selection of R. canina (or R. corymbifera or whatever in the messy canina clan) which I understand is low on thorns as well. Inermis is propagated by seed, when it is to be used as a rootstock, so the thornless trait breeds true (may be helped by the canina meiosis and self pollination, but still a very clear example of true-breeding thornlessness in roses; I wouldn’t suggest going back to inermis as a source for thornlessness, as it is really huge and thornlessness may well be recessive, requiring a number of selfings and backcrosses. Otherwise, one could use it for pollen with a diploid seedling, and could obtain a carrier for thornlessness. I actually tried using Kordes’ Lupo (a diploid single mini) as a seed parent with pollen from an inermis speciment growing feral on a roadside, without any doubt an “escaped” rootstock, but got no hips out of the 15 or so blooms i pollinated; may try harder next year. I’ve not enough space to dig further, though.

PS: for those interested, Austin’s Kew Gardens is virtually completely thornless. It’s a single white, but very healthy and blooms a lot. Very vigorous, may be too much so for those in hot areas. Sets many OP hips, never tried pollinating

I quite agree about the array of potential sources of thornlessness among species rose selections. However, I should point out that the background of modern cultivated Rubus is actually much more complex than you have stated. A large group of commercial berries are actually polyploid hybrids involving a number of species (the trailing cultivars are often referred to as “hybrid berries” for this reason), and the genes conferring thornlessness generally transfer well within the respective interbreeding groups. Among upright blackberries the sources were ‘Merton Thornless’ and ‘Everthornless’, and in trailing hybrid berries there are generally found genes derived from ‘Austin Thornless’ (a dewberry that probably originated from two species, Rubus flagellaris and Rubus argutus) or ‘Lincoln Logan’ (a tissue culture sport of ‘Logan Thornless’, which is a sport of ‘Logan’, a hybrid that arose from a cross between either a tetraploid cultivar of R. idaeus or an unreduced gamete of a diploid cultivar and an octoploid form of R. ursinus). The thornless trait found in red raspberries also suppresses prickles in purple raspberries (such as ‘Glencoe’), and is now slowly being introgressed from them into blackcap raspberries (there were once thornless cultivars of R. occidentalis, too, but they are believed to be extinct).

My young Kew Gardens didn’t survive, although I didn’t keep close tabs on it at the time it failed and can’t say just what happened; sometimes grafted roses have trouble getting established here. Lack of summer heat certainly wasn’t an issue! Another David Austin rose that is very smooth-caned and relatively healthy here is Mary Delaney–I’ve come to like that one a lot, although I haven’t observed any outward signs of fertility and haven’t tried using it in any crosses yet. I won’t mention its earlier, better known trade designation out of respect for the victims, but everyone can figure that out on HelpMeFind if they like.

Stefan