Common historical origin for the inactivated flowering repressor mutation is Parks Yellow. Alas long lost.
It is the prototype of dwarf recurrent large flowered roses.
Much more influent than any other chinese imported founder roses it is present and preponderant at all roots of all modern rose pedigree trees. Its more inbred progeny being continually the recurrent (both repeated and large flowered dwarf repeating) parent of the not numerous outcrosses.
Very, very little shematizing one can say that for the last two centuries Hts Fl and miniatures were bred selecting for Parks features.
Willing or not eliminating foreign genes. A side effect is the erased genetical diversity and consecutive uniform desease susceptibility.
Mutated repressors even with a common location were found to be diverse.
No wonder the Fabrice Foucher team is planning to (or working at) investigate its variations both in man bred roses and in more or less repeating species.
Extrapolating here are some thoughts of mine:
More universal and primitive than regulators of OF/RF flowering are the juvenile phase regulators.
It is this regulation that i.e. delays rugosa seedlings first flowering.
Once flowering regulation probably derives from juvenile phase regulators.
So much that inactivation of the flowering repressor induce the very short juvenile phase so obvious among our recurrent seedlings.
I also thank you Larry. From what you have written here,
Last summer my peachy creeper had 42 leaves below the flower on a 2 ft or so cane while N.D. had a considerably longer cane with just 14 leaves.
Does internodal length have any thing to do with “flowering” ?
From my work perspective with grapes, nodal length has a lot to do with bunches per cane, closer to the “cordon” of the vine the bunches are better, I guess what I am saying is closer to “lignifide”(spelling) wood does a “climber” bloom or is that in reverse.
For those needing any more arguments that foreign (from Parks) genes were eliminated is demonstrated by frost susceptibility of most modern roses.
Considering sampling main outcrosses how much gallica(!!!), fedtchenkoana, multiflora, foetida and wichuraiana are more frost resistant than modern roses one see how much it was eliminated selecting for Parks features.
Rereadind this I just wrote: "Mutated repressors even with a common location were found to be diverse.
No wonder the Fabrice Foucher team is planning to (or working at) investigate its variations both in man bred roses and in more or less repeating species.", I would better write:
Mutated repressors even with a common gene location of transponed area were found to be diverse. So that diverse expressions are not unlikely.
No wonder the Fabrice Foucher team is planning to (or working at) investigate its variations both in man bred roses and in more or less repeating species.
Kim, I’m not quite sure what it means about the # leaves. That was late at night here. But it is something like this. Floral identity genes, and floral induction genes somehow integrate information about number of phyllodes (leaves etc) are being cranked out at the meristem. After the integral reaches some number, then a flower is induced. Several groups did studies on blind wood in glasshouse roses some years ago. In that instance there is a predictable number of leaves per CV, with a flower to follow. But at too low light intensity (therefore sugar) it aborts. Later an axial bud may grow out and flower. That might have fewer leaves before the flower than would a basal break. Florists select(ed) for very regular production of x number of leaves (probably x = 7 or 8) from a basal break. That gives uniform longstemmed roses, of course varying with internode length. I believe the claim was that you could select for the leaf number in the seedling stage and it would hold up for the mature plant. Again with different internode length, stem diameter etc.
So last summer I counted leaves below bud on various CV. But I didn’t write it all down so I don’t remember too much of it. In the recent paper that got us all started they talk of climbing sports of bush roses. To be definitively a a once-flowering climbing sport the number of leaves below bud would have to be as many as could grow in a season.(=infinite maybe). That isn’t the case actually in many instances. What happens is they make 14 or 28 or whatever leaves instead of 7, then pop a flower if the season is long enough. That’s why the climbing sports are notorious for only being useful in mild climates (not mine before this year). And with long internodes they get really tall. That’s N.D. , both in PA and KS. What surprised me was how few leaves it actually was. I had long assumed it was a great many. Peachy Creeper is really more “climber” than N.D. in terms of flower induction with 42 leaves. (That was true on three stems, not just one). But it has very short internodes and weak floppy stems so it just sprawls a bit. I don’t have Red Cascade any more, but it was like that for me.
The ultimate extreme from this is Rainbow K.O. which mostly has 3 leaves per flower. Even its most vigorous basals have few leaves below the first flower. The plants were too thorny for good investigation, and there were very few such shoots in the unpruned plants on campus. Mostly it just build and builds… And so do its seedlings. With short internodes this makes dreadful stubby plants. Either RKO has some major modifier genes, or the floral gene being discussed earlier has a different mutation in RKO than was reported as being derived from the Chinas.
When it gets hard counting is when plants build on old wood year after year. What is a “basal break” in something other than the classic, grafted, heavily pruned HT? I see them only rarely, unless freezing knocks things back a lot. But I intend to take this seriously this year. I know some CV are rather variable, but we ought to be able to get averages for particular climatic conditions.
Pierre, I heartily agree that the Chinas brought us a lot of grief with the good.
With leaf number and internode length both determinants of plant architecture we enter in another subject
with incidences in growing-pruning strategies for greenhouse roses with forced basal breaks and so on… very refined and quite remote from garden roses.
I.e. internode number is not that simple as there is a variable and difficult to count number of condensed ones at branch base.
In earliest shoots rugosas and many other roses OF or RF send condensed flowering shoots. It is the rule for many OF species and hybrids. Internode number vary along with branch position and is a gaussian distribution.
It is something I know as I grew florist roses and thirty years ago my first attempts at rose breeding were aimed at these.
It is such an ample topic.
About the Chinas it is a pity that so few were available for so long but the grief is for pedigree and greenhouse breeding and that there was so much emphasis on some elements (color and ideal flower model) at cost of all others such as performance, resistance or adaptability in the not so easy for roses environments.
I wonder if this is what I read in the ARS the 1970s (?) where it was determined in florist production that it took an average of 35 perfect leaves to make one perfect flower? That information influenced my “pruning theology” very early on, encouraging me to permit plants to grow to their “desired potential” as much as possible to produce their greatest display of color. In that old climate, it worked like a charm as most were incredibly productive and demonstrated the greatest health they were capable of in that environment. Few were duds and even fewer were terminally “sick” when considering how many different cultivars were on that hill.
Thank you, Pierre. I’ve gone down the florist rose in the garden road. It was fun trying so many but that was in a very beneficial climate where they could pass without chemicals. At this stage of life, the rose has to perform and do it cleanly, or it’s out of here.