See:
http://www.zfdergi.ege.edu.tr/zfdergi/edergiziraat/2018_cilt55/s3/06.pdf
Saglam, H., Misirli, A., Flower Bud Differentation and Growing in Rosehip, Ege Univ. Ziraat fak. Derg., 2018,55 (3):291-297
ABSTRACT
Objective: In this study, it is aimed to observe differentiation of flower buds and their development in rosehip which has been appreciated in recent years due to vitamin C content.
Material and Methods: For this purpose, samples of flower buds were taken periodically in december-may period for two years from the rose hips bushes grown in natural flora. Then, microscopic examinations made in these samples to determine the development stager.
Results: As a result of the research, it was determined that the time of differentiation in the flower bud of rosehips grown naturally in lzmir Kemalpasa’s habitat, occurred in early February. Following morphological differentiation, it has been determined that flower organs have completed their development in a short time. Since the morphological differentiation took place in a very short time, some developmental stages were found to be intertwined.
Conclusion: The morphological differentiation time of the flower bud in rose hips differs from that of other Rosacaea family fruits. In general, the differentiation of flower buds in the fruits belonging to the Rosacaea family occurs during the summer period, while the morphological differentiation of the flower buds in the rosehips occurs during the winter period.
This is an interesting subject that should be pursued. In some strawberries, for example, floral differentiation occurs during the short days of autumn. In other plants, the differentiation occurs during winter dormancy.
I have not found any discussion on the inheritance of the timing of floral differentiation. This is of some interest to rose growers because some varieties are everblooming only in winter, if weather permits.
Thank you Karl. I guess I should always test a link on my wife’s non university computer.
I’m pretty sure the “rose hips” being discussed are wild roses, not the hips.
I would like to see a similar study of Rosa foetida. I have a suspicion that floral differentiation occurs during the summer dormancy, at least when the plants are allowed to have their normal summer dormancy.
Karl
If I’m not mistaken there have been studies on the timing of when flower buds are formed in a number of rosaceae, and in fact for some it is in winter, not in summer. That’s why you have to have a winter chill to get flowers on some fruits. Strawberries do it in late summer/fall except ever-bearing ones. Raspberries and blackberries have been looked at I know. Primocane types are like everblooming roses of course.
Does R foetida require cold to bloom? How far toward the equator will it perform? Both daylength and temperature may matter. Vernalization sets the flowering clock for many things that bloom in the spring.
As I recall, English growers observed that Rosa foetida flowered best where it was exposed to full sun during the summer. This is what led me to suspect that summer heat played a role.
Cape Belladonna (Amaryllis belladonna Auct. non l) also (reportedly) needed to “roast” during the English summer before it would flower freely.
I was researching both Rosa and Amaryllis at the same time, and noted some parallels. For instance, Peter Collinson wrote to John Bartram that he had been able to pick roses on Christmas day throughout the 1850s. And during this same period, Philip Miller recommended growing Cape Belladonnas in the open ground. It was a warm decade. The Cape Belladonnas fell out of favor in the cooler1760s and 1770s.
Karl
I tried searching for flower induction in rosaceae. Lots on strawberry, some on blackberry and raspberry, little on once-flowering roses. Someone living in coastal Cal could give us the answer. Does foetida bloom in S.D., San Jose, S.F.? S.F. sure isn’t hot in summer or cold in winter but it might grow really good B.S.
Larry,
A bunch of years ago I came across some info on floral initiation in peaches, and maybe some plums. That’s when I got to wondering about other variations in timing.
When I was in my late teens, I think it was, I learned that lilacs had nearly complete but really tiny inflorescences packed inside buds by late winter. I cut open a very few just to marvel at the miniatures.
I once saw Rosa foetida bicolor in San Jose, but I hadn’t thought about floral initiation at the time.
I did observe two distinct cultivars, both identified as ‘Harison’s Yellow’. One bloomed all at once, so I’m guessing that floral initiation took place in the winter … or earlier. The other continued to bloom over a longer season, apparently with new buds forming during spring and summer.
Karl
There is the nice paper by Dr. Andy Roberts and others from 1999 where they looked at the role of gibberellins on flowering in some roses. It seemed like that from their experiments that flower initiation in the roses they were working with occurred in very early spring as the roses were waking up and they could inhibit one time blooming roses from flowering by a strong external supply of particular gibberellins. The Effect of Gibberellins on Flowering in Roses - PubMed
Thank you David. There is a nice 2012 article that cites Roberts et al, and it’s a free PMC article. I found it from it citing the abstract you linked. I think I read it previously but totally forgot. They compared CF sport Little White Pet with its R wichurana hybrid parent that is OF. Varied doses of GA were tested and varied durations of dosing. The GA works through the gene that is mutated in CF roses like LWP. Vernalization functions to downregulate the wild-type of that gene long enough to allow flower induction, in a number of plant species, presumably rose also.
Uh … ‘Félicité et Perpétue’ is supposed to be a Hybrid Sempervirens.
I have found other reports that discuss the roles of polyamines in flowering. For instance, Tarenghi and Martin-Tanguy (1995), studying Fragaria ananassa Duch., found evidence suggesting “that ornithine decarboxylase (ODC) and polyamines are involved in regulating floral initiation in strawberry.”
Karl, my error in speed reading. The authors used R wich and F & P which they simply call R hybrida with no comment on whence it may derive. I presume they used R wich as a readily available OF rose and F & P as a OF parental type for Little White Pet. I conflated the two observations but have no clue the actual parentage of F & P. This is how the literature gets garbaged or garbled.
I have not yet found the info I’m seeking for Rosa, but I did find it for Rubus. That is, different species within a genus may begin floral initiation at different times of the year. In this case, a red raspberry got going the in late Feb and early March. A blackberry, on the other hand, was way ahead of the game by finishing late August, before winter rather than after.
This does not prove that R_osa foetida_ does its differentiation in summer, of course, but there is the possibility.
Amer. Soc. Hort. Sci. Proc. 19: 194-200. 1922.
Fruit bud formation in Rubus and Ribes.
L. H. MacDaniels,
Cornell University, Ithaca, NY
p. 195
Mar. 3, 1917 Herbert Red Raspberry. Flowers differentiated, but very small-—much smaller than with the black raspberry at the same season.
p. 196
It is quite clear that the flowers of the Snyder blackberry differentiate about the last of August. There is little change taking place between September and March.
I finished OCRing the above paper.
http://bulbnrose.x10.mx/Heredity/MacDanielsRubusTiming1922/MacDanielsRubusTiming1922.html
In some of the old literature, there are mentions of species and cultivars that need heat to “ripen” the wood. And there are warnings about some types that won’t flower well if they are pruned. It may be that these imprecise statements have to do with the time of flower bud differentiation.
For example, the Snyder Blackberry differentiated its flower buds in late August. In that case, September would not be a good time to prune the plants, because too many buds would be lost. But with the Herbert Raspberry, bud differentiation occurred in early March, which would give the grower a chance to remove any frost-damaged canes and branches in February, before floral initiation began.
Then there is the question about progeny. If one species differentiates its flower buds in the heat of August, and another puts the buds together in the cold of early March, will hybrids be at all confused about floral differentiation? Rubus hybrids are often fruitful even when we might expect some reduced fertility; e.g., the triploid Mahdi Berry. Roses might be another matter.
In another paper I read: Goff, in a comparison of apple varieties, found a variation of as much as five weeks in the time of flower-bud formation.
I haven’t found Goff’s paper with the details, but it is easy to see how the performance of various cultivars could vary independently, year to year, even when they are growing in the same conditions. A lot of weather can transpire in five weeks, and so the specimens of several cultivars may be differentiating their flower buds under different immediate conditions.