“Unexpected” reblooming seedlings is a common experience.
Even in crosses involving a species parent.
Many recent european papers state there are no reblooming genes.
On the contrary there is are genetically determined once-blooming.
These findings were not presupposed as years before we exchanged some said papers authors and me about seedlings not fitting reblooming genes theory.
In fact they were looking for the recurrent flowering genes and did not find any.
Findings were that flowering suppression (=once blooming) is genetically determined.
Musk x gallica should not rebloom, therefore
(Musk x gallica) x fedtschenkoana should not, therefore
spinosissima x (Musk x gallica) x fedtschenkoana should not, therefore
spinosissima x (spinosissima x (Musk x gallica) x fedtschenkoana), AKA Paula Vapelle, cannot possibly rebloom.
That sequence runs from pre-history to the 21st century without any of them having two known rebloomers as parents, and is probably the temporally longest example, but even if you look at breeders who have recently posted here, you can find the same. Off the top of my head (since I’ve been working with Nightmoss):
Neither Nuits de Young or Tuscany Superb rebloom.
Nuits de Young x Tuscany Superb should not (and does not) rebloom, therefore
its seedlings, Janjin Malgai and Jon Singer, probably shouldn’t.
Yet both do, and there are a number of different posters here whose roses would work in that example in place of Barden’s and Shimbo’s.
I look forward to the day when genetic analysis is cheap enough to get all this sorted out. The obviously Mendellian, chinensis sort of breakage seems clear enough, but so much else isn’t.
Hardy,
Thank you for more examples. However, the old Musk rose does bloom continuously, and Fedtschenkoana produces scattered late bloom.
Long before I began keeping notes, I wondered about the rebloom that turned up so frequently when breeders began hybridizing among related species.
Variations in ripening time also occur. For example, Burbank crossed two very late ripening cherries. Among the offspring he found the earliest ripening cherry he had ever seen. Similarly, crossing among three late ripening American plums gave an early ripening variety.
Here is an article that is highly technical, but gives some insight into the complexity of the flowering mechanism:
Plant Cell. 2004 October; 16(10): 2601–2613. Divergent Roles of a Pair of Homologous Jumonji/Zinc-Finger–Class Transcription Factor Proteins in the Regulation of Arabidopsis Flowering Time
Bosl Noh, et al.
Abstract
Flowering in Arabidopsis thaliana is controlled by multiple pathways, including the photoperiod pathway and the FLOWERING LOCUS C (FLC)-dependent pathway. Here, we report that a pair of related jumonji-class transcription factors, EARLY FLOWERING 6 (ELF6) and RELATIVE OF EARLY FLOWERING 6 (REF6), play divergent roles in the regulation of Arabidopsis flowering. ELF6 acts as a repressor in the photoperiod pathway, whereas REF6, which has the highest similarity to ELF6, is an FLC repressor. Ectopic expression studies and expression pattern analyses show that ELF6 and REF6 have different cellular roles and are also regulated differentially despite their sequence similarities. Repression of FLC expression by REF6 accompanies histone modifications in FLC chromatin, indicating that the transcriptional regulatory activity of this class of proteins includes chromatin remodeling. This report demonstrates the in vivo functions of this class of proteins in higher eukaryotes.
Two species, or even two races of a single species, may regulate flowering in different ways. Thus, crossing among wild forms can produce results similar to what is found in mutants.
And another:
Plant Physiol. 1966 January; 41(1): 111–114. Inheritance of Factors Affecting Floral Primordia Initiation in Cestrum; Hybrids of C. elegans and C. nocturnum
Wesley O. Griesel
Abstract
Photoperiod patterns of hybrids of Cestrum elegans (Brongn.) Schlect., a day neutral plant, and C. nocturnum L., a long-short day and long day plant, were investigated. Plants of the F1 generation, F2 generation, and backcrosses to each parent were tested on short day, long day, continuous light, long-short day and short-long day for floral primordia initiation. The data recorded suggest 2 independent genes or gene groups controlling floral primordia initiation in C. nocturnum, a single dominant gene that is activated by long-short day treatment and a recessive gene or genes responding to long day treatment. Further, these data suggest that the day neutral condition in C. elegans is the result of the series of independent genes or gene groups that respond to various photoperiods, the combination of these genes resulting in floral primordia initiation on all photoperiods.
“An examination of the hybrids, both F1 and F2, gives some insight into the pattern present in the DN plant, C. elegans. There is almost complete lack of flowering on LD in the F1 generation, while the parent plants bloom readily on that photoperiod. There is, however, a high percentage of F1 plants that bloom on an 8-hour day, while C. nocturnum does not do so, and a substantially greater number on CL than on LD.”
A little more about Cestrum:
Photoperiodism (1959)
“Cestrum nocturnum, a member of the Solanaceae, has also been described as a LSDP (Sachs, 1956a). Cestrum will remain vegetative if grown continuously in LD or SD conditions, the sequence of LD followed by SD cannot be reversed, and there is no morphological change at the terminal or axillary buds until sometime after SD induction is completed.”
In other plants, temperature may be the controlling factor.
Went: Thermoperiodicity (1948)
“Another set of phenomena, which are closely related to vernalization, are the chilling requirements for development of buds of deciduous trees. In most of these plants the buds are dormant for a considerable part of the winter, and can be forced into growth only after having been subjected to freezing temperatures. In some cases the low temperatures may have no other effect than supplying a stimulus, so that a definite time after being subjected to a sudden drop in temperature, irrespective of the duration of this lower temperature, development occurs. The flower buds of the orchid Dendrobium crumenatum offer a clear-cut example (COSTER 1926, KUIJPER 1933). Nine days after a sufficiently rapid drop in temperature (usually associated with a heavy rainfall) the flowers of this orchid open, causing a sudden burst of flowering over a wide area. Some other orchids seem to behave in the same way, and probably other plants as well (gregarious flowering of Coffea liberica). In these cases the flower buds develop gradually up to a certain point, beyond which no growth is possible under the prevailing temperature conditions. The longer the temperature drop is delayed, the more flower buds will have reached the critical size, and the more abundant the flowering is after the temperature drop.” http://bulbnrose.x10.mx/Heredity/WentThermoperiod1948/WentThermoperiod1948.html
The situation becomes very interesting among hybrids of parents with very different modes of flowering regulation. We should also note that floral initiation, which often precedes flowering by several months, may occur at different times in different species.
Thanks for the link, Rolf. To clarify, all of the everblooming blush series are albas?
Some beautiful plants in that collection! I particularly like some of the warmer colors, as they are a little more surprising to me.
Are you willing to divulge any info on pedigrees, or how many generations removed from the Albas these cultivars are, and what percentage alba they contain?
1B30 is a key parent I like to use that transmits health and sometimes stipples (dad of Oso Happy Petit Pink). It has in its background an open pollinated seedling of ‘Applejack’ which is likely ‘Applejack’ x ‘Alba Semi-Plena’. Here is a link to 1B30 on helpmefind. '1B30' Rose The ‘Applejack’ op was a seedling of Kathy Zuzek’s and ‘Alba Semi-Plena’ was growing next to ‘Applejack’. The growth habit, large flowers, foliage color, etc. of Kathy’s seedling all suggest the alba neighbor being the most likely male parent. I wonder if there are some unique resistance genes mixed with the disease resistance genes of the other roses that led to the health of this line. 1B30 is one time flowering, but has a long season of bloom of bloom and gives ~50% reflowering seedlings crossed to repeaters. It is a bit difficult to root from cuttings, like its dad. Unfortunately, the likely alba in its background is diluted a lot.
We may find in many cases that different species achieve the same end by different means. Just as one sometimes finds disease-prone seedlings bred from resistant parents, it should be possible to find increased resistance in some selected progeny … but only if we are looking for it.
I am reminded of a somewhat similar case:
The Cottage Gardener 7(176): 303-305 (February 12, 1852)
BEDDING GERANIUMS
Donald Beaton
“The best doctor for our present purpose, is he who can infuse the hardihood of the wild Cape Geraniums into the new race of fancies, for most of the wild ones are much more hardy than the generality of the prize sorts, as I have proved over and over again, having the two growing side by side in the borders of a conservatory wall, where it was very rare indeed to lose a Cape species in winter, and where no winter passed, however mild, without leaving blanks in the large sorts.”
In other words, gardeners and florists seeking larger, showier flowers, had managed (inadvertently) to “breed out” the hardiness of the ancestral Pelargonium species.
Breeding pelargoniums in a greenhouse would be like breeding roses while spraying all the seedlings with anti-fungals. We won’t know what we have done until it is too late.
