Then there is ‘Frau Karl Druschki’, which is a vigorous once-bloomer on its own roots, but becomes a freely reblooming dwarf when grafted onto a suitable stock. ‘Reichpresident von Hindenburg’ behaves similarly, according to Nicolas (1937). He further wrote, “Some of us old timers may remember an early Van Fleet Hybrid Tea, Magnafrano (1900). For years it was sold on its own roots and it remained a typical Hybrid Tea. I budded it on Multiflora for breeding purposes and I got plants of Druschki exuberance, thus emphasizing its seed parent, Magna Charta. It is from one of these plants that I bred the climber Virginia.” http://bulbnrose.x10.mx/Roses/breeding/Nicolas_Lambert1937.html
And checking through my pictures I find that I have shots of ‘François Foucard’ blooming in March, April, May, August and September. Not bad for a once-blooming Hybrid Wichuraiana.
This speaks again to Professor Davis’ comments about florigen crossover. I was thinking more about gene dose effects due to ploidy level and gene copy number.
I have shots of ‘François Foucard’ blooming in March, April, May, August and September. Not bad for a once-blooming Hybrid Wichuraiana.
I don’t know whether it was budded or on its own roots. It was such a massive plant I didn’t venture to take a look at ground level. I have only seen it at the Heritage Rose Garden (San Jose). ‘François Foucard’ bloomed much more than the other Luciae hybrids, such as ‘François Juranville’ and ‘Paul Noël’, and the Hybrid Wichuraiana ‘Gardenia’.
I should mention that the earliest (March) and latest (September) blooms weren’t as abundant or as well formed as the others. There may have been blooms in June and July, but I didn’t take pictures of them – there were so many other varieties in bloom, and I already had enough shots of ‘François Foucard’. It has a delicious perfume, by the way.
Back to the original question in its simplest form. If I read correctly, flowering comes when there is a certain balance of a “yes” and a “no”. If “yes” is ahead, then a flower shows up soon. If “no” is ahead, then no flower at this time. We know that at least one gene in the “China rose” line was originally a strong “no”. Only a good winter could tip the balance to “yes”, and that happened only once in spring or summer. Then a transposon got inserted into the “no” so it wasn’t able to outdo “yes” for one chromosome. Proper inbreeding resulted in “probably” a diploid with two defective “no” genes, so a continual rebloomer. Eventually this trait was transferred to tetraploid roses. But it appears that at least for floribundas and HT, even one strong “no” will outdo four “yes”, except after winter. That comes from the work of Semeniuk. The “no” gene is called RoKSN these days. As a defective gene it behaves as a recessive trait. It is identified as being defective at one specific place in the gene in many different cultivars. One healthy version makes enough product to win the game.
So far, I’ve not seen a report that the exact same defective gene is operating in R multiflora nana, or R rugosa, or in some autumn damask. I may have missed that identification.
Because the determination of flowering is a balancing act, we can think of several ways to tip the balance. Making lots more of the “yes” gene product would be one. Possibly one or more rose species has a duplication of the “yes” gene.
Suppressing the action of “no” by some other controller would be another. For instance a microRNA could do it.
There may also be a whole pathway that we know very little about, whereby dormancy without cold, can trigger overproduction of “yes” under newly favorable conditions. Our prairie R arkansana may have that trait. I’ve seen what appear to be new basals shoot up when all the achenes/hips are destroyed by bruchids early on, and then water is applied. Or when roses on a verge are mowed repeatedly and rain comes in autumn. Other species may possess comparable interesting tricks. We have flowering crab apples nearby the bloom almost every autumn, plus spring.
Something mentioned by Karl, and perhaps others, is that we need to think of some other woody rosaceae as potential models. Apples for instance, have a juvenile phase with no flowering or fruiting for years. Roses not having the defective “no” gene do the same. Repeat flowering within a single season may happen with maturity, for instance in R rugosa. Rapid (re)production by use of grafts may keep many plants in perpetual juvenility. Only when they can grow mature, without freezing back, will they repeat bloom. That’s a common character in the climbing sports of HTs when the transposon that makes the “no” gene defective, pops out, making it sort of effective.
Undoubtedly daylength enters into the flowering cycle of plants that live in any temperate zone. We’ve mostly selected that out of roses, focusing more on winter as a controller. I don’t know enough about mild climates to comment much more on this one. I have seen callery pear in bloom in L.A. in November. That is almost certainly a daylength, not a winter effect.
Thank you Karl for reminding up of how earlier growers and breeders made valuable observations. Perhaps not all are correct, but surely there must be something to them.
Thanks, Larry, for the cogent summary. That’s what I need to understand these things.
So the “yes” gene is defective.
Does that explain why, among my OP Prairie Joy seedlings, there seemed to be 10 vigorous non-bloomers for every one really runty everbloomer? It seemed like the difference in vigor went beyond the explanation of energy diverted to flower production.
Coal smog was a big problem between about 1840 and the 1950s, but that’s when people were breeding HPs, bourbons and later types. Damasks, albas and centifolias were really all done by then, and gallicas were quite close.
I’d propose instead that, between 1800 and 1840, pathogens were imported into Europe and North America, including RMV and foreign strains of blackspot. People subsequently saw roses which had always been healthy getting sick for the first time, and said they’d lost their health, but only the disease environment had changed. In places where the newly arrived pathogens proved well adapted and settled in for a long stay, maybe old European cultivars still don’t do well. That’s my speculation on the subject, anyway.
Where I live, albas and damasks are vigorous, and impervious to the PM and the one race of blackspot that saturate the area. Autumn Damask has been growing wild at an nearby, abandoned Spanish-era ranch for well over a century, and keeps on going without any spraying, fertilizer, waterings or coal smog, despite regular predation by deer. AD is also #2 on my list of highest germination percentages for the year, and the seedlings have been well formed and healthy. While it doesn’t make enough seeds/hip for me to keep wanting to use it as a seed parent, I’m really looking forward to using it as a pollen parent. It’s undoubtedly a great choice for gardeners in my area.
Meanwhile, I shovel pruned Duchesse de Brabant and KnockOut for being covered with PM, and put Bonica onto blackspot probation; most roses do get sick here, including a number of “very disease resistant” cultivars. A few species automatically mildew, and while it’s not hard to avoid eglanteria and its hybrids, steering clear of chinensis and its hybrids is a lot tougher.
While some have gone so far as to suggest that crossing with chinensis is a bad idea that will break your rose’s disease resistance, I know that some of you are happy enough with that species, and am willing to accept that it’s healthy in some areas. With many thousands of hybrids to pick from, some can be found which are healthy almost anywhere! If 95% of breeding for the last 180 years had been centifolia hybrids, I don’t doubt that there would be plenty of healthy centifolias by now, too. A lot can be accomplished in 20 generations.
I’d therefore like to encourage an open minded approach when it comes to declaring classes of roses as categorically bad, because the rose you consider hopeless may be spotless and unkillable somewhere, and somewhere your area’s very best rose is not going to survive.
Joe, the “yes” gene may be deficient to satisfy our desire for repeat bloom, but it’s not obviously defective in the way that the “no” gene is with rebloomers. The “no” gene has been mangled beyond recognition so it stops saying NO.
The 10 :1 ratio suggests 9:3:3:1 very roughly speaking which would be what you have if there are 4 possible chromosomes and half are dominant, half recessive for a trait in your Prairie parent. Look up Punnett square, dihybrid cross online to see a ton of examples. The runtiness probably has nothing to do directly with the flowering habit, but instead there may be some (un)vigor genes on the same chromosome as the “no” gene. So most of the time runtiness and rebloom come together by bad luck-linkage. Doing a back-cross of the repeat-blooming runt to somewhere near half of the vigorous once-bloomers may give decent reblooming offspring if you can get some “independent segregation” of traits. Depends how strong the linkage is. The others can only give once-bloomers. Of course we don’t know which once-bloomers are in which group without testing them all. That’s all fine and dandy for maize, but way to tedious for roses. That’s why we really need a simple screening test at about $1 per.
If vigor really is linked to the rebloom trait in this CV, you might expect a whole range of plant vigor with the most vigorous having zero “no” gene defective, and the less vigorous having more copies of the"no" gene defective. So you could guess to back cross onto the less vigorous once-bloomers and have a higher chance of rebloomers. Making a flower doesn’t take all that much of the rose energy if there are at least half a dozen leaves produced per flower. The total mass of flower output per plant is not very big as a fraction of total mass accumulated in a season, even for Carefree Beauty, or Knockout.
Seed and hip production is a different matter depending on seed and hip mass. But mostly it is about plant hormones, not energy as such. Check out the yield of an established apple orchard ( dry matter, not juice). Then imagine how much multiflora that is per acre. Five to 10 tons would be a reasonable estimate of potential in Illinois or Iowa.
I’m not sure how you understood that I was labeling any group of roses as hopeless, or advocating any other as perfect. My intent was to call attention to a factor in disease/health of some roses that are often rather uncritically grouped together as old-and-therefore-good roses. Yes, they are good in some places, and not good in others, and in some places afflicted by pollution they did much better than they do in some places where we’d expect them to do better. I did mention a number of factors: “different environment–different climate, different pollution levels, and maybe different fungal ecosystems . . . and maybe evolution of fungal strains.”
Maybe pathogens were imported to North America and Europe, though I don’t know specifically where they would have come from, or who would have had the foresight to import them, or who would have issued the phytosanitary certification for such exports/imports. The wind moves where it will, and APHIS and other agencies blunder on behind.
My guess is that the pathogens were there all the time, but putting lots of roses in one area led to the same problems we have found with monoculture of almost anything–the concentration of insects and diseases that thrive on those crops.
According to fairly recent research, there are 16 or so strains of blackspot. Some roses are resistant to one or two, some to maybe 3 or 4, but probably no roses are immune to all. I don’t know how many strains of powdery mildew there are, or how many strains of downy mildew–but there are too many to suit me.
I do understand that Knock Out and its sports suffer greatly from powdery mildew on the west coast of the US. I also understand that the same cultivar may get raves and rants for both disease resistance and susceptibility in areas very close to each other. Often what is credited to a cultivar’s genetic makeup should be credited to its location or the climatic conditions instead (including pollution if that is present).
The Earthkind program assumes regional factors in the health of roses, and I think there is some evidence to support that. Certification in one area should not be understood to mean a rose will be healthy in another. One of the first Earthkind winners in Texas was defoliated most of its first season here in Charleston, WV, and did not survive past the second season. (I credit my award-winning fungal population for that.)
The three most important words in rose health are Location, Location, and Location.
We have worked to improve disease resistance in roses, and we have had some success, but we need to keep working on it. Maybe someday a rose will be truly “bulletproof” (that is the term I’ve seen applied to quite a few roses that were defoliated by blackspot a month into the season here), but I doubt it. Not in my lifetime, and probably not in yours.
And (to make a bow to the original topic of this thread), even once-blooming roses get disease. It’s a rose’s nature.
While a once bloomer seedling as long as water and nutrients are readily available grows steadily above and under soil surface, a reblooming oneas it has been clearly observed in hydroponics is more stop and go. When producing a flower flush roots elongate and stop part time roughly when stems do.
Add to this the costs of producing flowers and fruits that hinder growth you can induce that average reblooming seedling is no more than 25% the weight of a first year no bloomer. Less in some lines.
That is why in early stages of seedling growth as soon as possible I routinely take of buds in order to promote first year growth. So that the rebloomers compete a little better in seedling flats.
Also often when planting in soil in order to get more roots and growth. Even for grafted strong plants.
Add to this the possibility that among OPs the reblooming seedlings were self pollinated when non rebloomers may be beecrossed.
Another point is:
Control of rebloom is not a single gene affair is evidenced in some crosses like with diploids such as Robin Hood: a larger growing china-polyantha. Among progenies one finds everything any size from microminis to strong ramblers. With in beetween every kind of rebloom, including some that are day length dependent.
No wonder southerners or greenhouse growers know that Teas or Chinas do not stop flowering as long as temps are above 0°C with a little sun when including most older HT reblooming OGRs usually do not.
Years ago I said it to the french scientific team leader that last time we met told me he was waiting for funding to explore diversity of reblooming control.
I’m germinating some (Belle de Crecy x (Carefree Beauty x John Cabot )) OP seedlings this year. I only have 6 seedlings so far but I noticed that one of them has a tiny flower bud on it. This proves that repeat bloom can be recaptured in two generations when working with once blooming OGRs.
Here’s a photo of E2804(Belle de Crecy x (Carefree Beauty x John Cabot))
Hi Paul, I made a comment earlier on about OGR. Due to record keeping back in the old days , most of the time the pollinator was not known. Belle de Crecy in HMF is listed as Gallica/China, this would account to having a repeat bloomer in two generations due the seed parent already having recessive repeating genes present. A lot of the OGR are not as pure in the breeding lines as one would think.
Hi Warren,
It certainly is possible that Belle de Crecy is a Gallica/China hybrid. Though to my untrained eyes it looked very much like the other Gallicas I have. If it is a hybrid then I got lucky because I didn’t realize that at the time I did the crosses. I have used three different pollens on BdC and got 40 seedlings from those crosses and none of those repeat bloomed. Over the last couple years I have also raised about 30 seedlings from two different Belle de Crecy x Frontenac plants and so far none of those have bloomed, but they probably have non juvenile repeat bloom and could bloom this year. So you can see why I was a little surprised to see the flower bud on this year’s seedling.
Thank you Pierre for giving us accurate information on how growth rates relate to reblooming in the practical way. My comments earlier were strictly from an energetic standpoint, not a hormonal one. Let me expand it a little.
For agronomic crops, back around 1970, a group of agronomists at UC-Davis (Robert Loomis et al) calculated the energy requirements for production of every material in a plant, such as sugar beets,. or soybeans. It does cost more to make protein than sugar, so sugar beet dry matter yield is much higher. Also the C-4 pathway of photosynthesis in maize is more efficient than the C-3 in wheat and rice. These facts set upper limits on productivity. Maize at 300 bushels/ acre harvested (roughly 15 metric tons/ha) is approaching that limit for the available season length and photosynthetic efficiency. The “stover” yield about equals the grain, so we’re talking of 30 metric tons/ha. Sugar cane or eucalyptus trees can do better because they have a longer growing season. A C-3 crop may be only 1/2 as good as C-4but still a lot of biomass.
Energetically we can calculate for pollen, petals and other parts what it costs to make them. There are some little differences for anthocyanins vs chlorophyll, or carotenes, and a slightly different protein or nucleic acid amount per dry mass in flowers vs leaves and stems, but not a whole lot. We could select for higher plant vigor such as Silver Moon, van Fleet vs New Dawn and then measure maximum biomass increase per year in a uniform stand with closed canopy. We could go the other way using something like Peace and its climbing sport. The difference in total biomass between van Fleet/ New Dawn or Peace/CL Peace, whatever it turns out to be, will be mostly the effect of hormones I would wager. I suppose I should actually do the calculations.
I just looked back in my notes to 1985 when I weighed 35 Carefree Beauty flowers (plus supporting structures down to the 1st true leaf) and got an average dry weight of 400 mg each. The C-3 crop of soybeans will give 1 kg/m2 implying you could have 2,500 flowers/m2 if flowers constituted half the newly formed biomass at the end of the season. The Knockout roses are heading in this direction. Typical HT or Fl might be 250 to 25/m2/season. We have lots of room for improvement before we reach energetic limits. So how do we change the hormones? That is the question.
