Well, not exactly but pretty close. This seems to be an overly ambitious project to direct the hearts and minds of hybridizers toward the philosophy of the Robinson brothers. Mostly they are targeting potatoes but a similar approach could also work for roses.
My own program incorporates a ‘last plant standing’ phase, in fact, with the hope of passing on survivors.
Does yours?
Link: opbf.org/
Pretty close. Nothing gets sprayed here, NOTHING. No matter what the cross, if the plant is weak or sickly, out it goes. I’ll grow more difficult crosses on as long as I remain interested and they perform, but once either limit is reached, they’re out, too. Kim
I can’t really comment on blackspot. But PM is what causes most of my seedlings to die or get weeded out. I do keep a few PM susceptible seedlings that other wise grow well so they can spread spores about. These PM susceptible seedlings I plant in the middle of my beds. Also drought and winter hardiness takes it toll on seedlings. Some time it amazes me that anything survives. If I had blackspot I would keep vigorous seedlings that always had it so they could spread it about.
I don’t have to keep infected ones to spread it, it’s everywhere here! I don’t spray any of my seedlings. I want to know if they are going to be disease freaks or not. But I rarely toss anything out either (so bad at culling 
). For the most part I’ve found the ones that are the most disease prone die out on their own over winter anyway because they’re small and leafless most of the season. It works for me.
You actually shouldn’t need to keep spreaders around to inoculate other plants, unless they are infected with something not indigenous to your area. As Seil said, the spores are EVERYWHERE and opportunistic enough to germinate when and where they find suitable conditions. Kim
Seil, I also cull mostly by attrition. I don’t spray my seedlings because most of them are Rugosas. Any Rugosa showing blackspot gets culled (luckily disease shows up before the first flower) but I don’t cull for mildew too early. My strategy for introducing new fungus spores to test my seedlings is to order more roses every year. 
Collect them from all over the country, Betsy, so you’ll get new strains of disease and accomplish Radler’s results! Kim
I have refrained from spraying with anything other than a Neem product called AzaMax, and a silica product called Pro-Tek. With the high levels of chlorine in the water, what I found was that not spraying was selecting for primarily high chlorine tolerance. The attrition rate is still high, but the plants now have a chance to build some natural resistance, but it is hard to call this no intervention. Anything that survives to one yr. and still shows any sign of rust, mildew or other disease, is then culled. So I believe I am practicing “last plant standing” with an asterisk. Weak and pathetic looking seedlings do not survive even with this intervention.
You’re saying much the same thing, Jackie. “Last man standing” is very much what I practice. Other than the Banksiae seedling, which all seem addicted to mildew intially, those with “issues” get culled quite quickly. I’ll grow them to the point of flowering to see what they’ll look like, but weak ones are generally those which don’t generate decent root systems under them, so will likely require budding to perform. As I don’t want to produce anything requiring budding, those go away real fast. I’ll continue with the Banksiae offspring long enough to determine if there is enough there to warrant putting up with any issues they hold on to. The longest running one so far will be two years old next April. It’s the seed from Lutescens which germinated in only four months from harvesting and planting. That’s now in a seven gallon can, growing on a bamboo tripod with a lot of wood on it. No flowers yet, hopefully this year? It would have been much larger than it is had the blamed rodent not taken a real shine to it when it was little. Every time it grew, he/she ate it. Kim
Yes Don roses are tetraploid and clonal propagated.
‘last plant standing’ and not spraying are essentially preliminary steps.
Population breeding is a combination of parent selection and random mating in order to build up horizontal resistance.
The closest to this strategy for roses is using mixed pollen on selected mothers.
Instead of pedigree Robinson objects, focus is on progeny.
Out of curiosity do roses ever outgrow a disease-prone stage during infancy to become good specimens when they have matured?
I think so. I know some of my purchased roses have become less disease prone as they established and matured. So I would have to think that some seedlings would as well. But I have no proof, scientific or otherwise, of that.
Some do. Think about it. An immune system, as with any other “system”, requires the organism to function as it was intended to. Anything which limits its ability to function will inhibit any of its systems from functioning properly.
With a new seedling or a newly planted bare root, or even a newly propagated cutting, there may not be sufficient foliage mass to provide the nutrition levels the plant requires for systems to perform efficiently. In plants such as many Teas, the immature plant may not have sufficient old wood mass required to store the resources for it to break dormancy as it’s genetically programmed. In either case, the root mass required to forage for and collect sufficient nutrients to support the plant appropriately may not have developed.
In all of these cases, the plant is basically malnourished and all systems can be inhibited, prevented from performing as they are programmed to. Once the plant matures, develops the wood, roots and foliage required to properly feed, shade and cool it, systems can function more as they are programmed to and health can improve substantially…or not.
Around these parts, Iceberg mildews on the peduncles year round. You can force Iceberg to black spot by hacking the devil out of it, denying it the foliage value it requires to perform. Its malnourished foliage is unable to resist the fungal attacks and it forms spots. On larger plants permitted to grow the mass it wants and can support, you seldom see any black spot effects. Many HTs here can be forced to rust. I forced my R. Arkansana to rust by allowing it to dry out too far, too early in spring, “tricking” it into “thinking” it was late fall and time to shed its foliage for winter. Once I began keeping the pot watered regularly, the new growth out grew the rust and it wasn’t an issue. Mildew can be forced by keeping the plant too dry. I read that years ago and didn’t believe it, until I forced it. Plants I’d never seen mildew on, I permitted to dry out rather severely in summer, when there should have been no mildew possible. Kept too dry, but watered enough to prevent death, they mildewed as if it was fall and when mildew should have been around.
So, yes, some out grow disease. Some disease can be forced by improper culture. Kim
Rugosa foliolosa derived seedlings are very rust prone by first autumn and not on following years.
Banksiae seedlings are very PM prone as young seedlings and just as mother quite tolerant as soon as tall enough.
Yes many seedlings are able to outgrow desease succeptibility.
Beside immune system building I fully agree there is another logical explanation: a dense mass of young foliage close to soil surface is very desease succeptible. The reason why there are so few BS resistant minis.
Decisive part of immune system building is meeting a right enough biologic environment for the place they sit. Plants just as other beings have a cortege, a numerous set of microorganisms that are from pacific to predators, living on plant wastes and or predating other microorganisms. These indispensable microorganisms cooperate in many ways and are indispensable actors of immune system. Meeting them or not takes a few monthes. Micorrhyzae some plants cannot grow without are among the better studied.
Not spraying we preserve cooperating microorganisms and allow natural biologic environment build up.
Pierre, I shared your post regarding natural biologic environment build up with another rose list I belong to and it has brought forth this question. While I don’t know of any research concerning its possibilities, it would make sense that it COULD be the case. Any thoughts, anyone? Thanks. Kim
"That’s really an interesting thought, Kim. Then a further question might be, are there symbiotic fungal and bacterial communities that exist in a particular habitat that don’t thrive as well in other habitats, so when you take a rose out of its preferred soil or habitat situation, one of the problems in the rose’s adaptation or thriving in the second is that the fungal/bacterial communities that the rose has depended on don’t exist there or don’t thrive there?
Is that a silly thought? or overly simplistic? you’re going to have me reading the rha!" See? I’m trying!
Isn’t this just Darwinian natural selection of strongest OP seedlings? They used to do that with roses for a long time.
I submit my seedlings to this, I sort of just abuse them in a pot all summer, the ones that show the healthiest vigor/rebound from it, get to a certain size, i.e. want to grow, get most attention.
My rose ‘Enjouee’ had two sisters that had pretty flowers (one looked more like an apple blossom with elongated petals) and speckles, but the plants proved to less disease resistant when absued in their pots all summer, while the seedling that would be ‘Enjouee’ recovered from powdery mildew. It was that seedling’s readiness to grow new foliage to replace diseased ones which caught my attention. So it wasn’t perfect but the fact that it rebounds quickly is an admirable trait. I planted her and then tested the others: if they overwintered in their pots, then they would be planed out.
Kim, I don’t know if I’ve read much about the matter, or if I’m just so opiniated as to assume it to be a given (and for that matter, I’m not sure I’m really understanding your question) but I firmly think that creating an environment supporting mycorrhizae and other symbiotic organisms is a first step to overall plant health. It seems to be born-out in my own garden. Chemical fertilizers may be a cheap option, and rapid growth may help a plant outgrow diseases, but I don’t know that it aids the beneficials much. I can neglect my plants grown in a mostly organic manner for years, whereas neglecting the same cultivar grown in a moderately chemical-dependent setting for a month or so will cause it to suffer terribly, and to succumb to disease.
I suppose it would be akin to keeping a person healthy by using antibiotics, versus ‘probiotics’.
I’m may not be understanding your question, however.
Max, that’s what Ralph referred to as “testing by stress”. The figured if he couldn’t kill them easily, you shouldn’t be able to. I think that’s what most of us do, if the seedling isn’t vigorous or has too many issues, it gets dumped.
Hi Philip, I’m not sure how much I put into the idea of supporting biological systems, but the thought does stimulate thought. That’s why I shared Gean’s question, to stimulate more thought on the idea. It makes some sense there would be symbiotic, support systems in place and their lack seems logical in the issues exhibited by roses which seem to “out grow” disease issues. The idea is still working its way through my head. Kim
“are there symbiotic fungal and bacterial communities that exist in a particular habitat that don’t thrive as well in other habitats, so when you take a rose out of its preferred soil or habitat situation, one of the problems in the rose’s adaptation or thriving in the second is that the fungal/bacterial communities that the rose has depended on don’t exist there or don’t thrive there?”
This is a field that only begins to get more attention.
In a few words one can say that a “symbiotic” microorganism community first environment is its host plant and further that this community has flexibility. Another point is that adaptation and flexibility are not without bounds.
Or from another point of view a “symbiotic” microorganism community is from an help one should not neglect to a limiting factor just as it is known many plants cannot be grown without a microorganism cortege.
Fascinating stuff! But aren’t most of us trying to create roses that do not only survive but thrive in most any soil and/or climate condition? Yes, I know, a little like seeking the Holy Grail but it is the goal isn’t it? Knock Outs have come closer to it but they do so lack appeal. I want a rose that’s as gorgeous as say Double Delight but will be as healthy, hardy and vigorous as KO is, and I want it to be that way in Maine, Michigan, Kansas, Florida or California, all parts in between and let’s throw in Canada, Europe and Australia while we’re at it!
In a perfect world we’d all have those lovely little microorganism communities in our soils but most people don’t. They have everyday ordinary garden soil with all of it’s lumps, bumps and diversities. And the average gardener isn’t going to know how or want to go to the lengths of making their soil that perfect. To really encourage a lot of people to want to grow roses you need a rose that will perform consistently in regular old backyard suburban soil conditions. And that’s the key reason that KOs are so widely hailed. Even though they do black spot here they’ll grow and bloom vigorously in anything anywhere. But, to me, they are just so BORING!