Rebloomers genes

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Rebloomers genes

Post: # 71579Post johannesp
Thu Jun 04, 2020 6:21 pm

Does anyone know if RoKSN (non-rebloomer) is dominant to akbp (climber)?

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Re: Rebloomers genes

Post: # 71721Post rikuhelin1
Fri Jun 19, 2020 3:20 pm

Nope not me , Unknown yellow started today - sending pollen Monday - only rose blooming in back north gardens.
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Re: Rebloomers genes

Post: # 71722Post jbergeson
Fri Jun 19, 2020 5:34 pm

That's a nice bright yellow, Riku.

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Re: Rebloomers genes

Post: # 71723Post rikuhelin1
Fri Jun 19, 2020 10:28 pm

Txs Joe, some of the tone is “natural deep clear” yellow, but it may benefit from being in a spot where it misses the direct morning and afternoon sun (shade trees). Receives late afternoon sun. I don't plan to use the pollen or cross it this year.

david zlesak
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Re: Rebloomers genes

Post: # 71729Post david zlesak
Sun Jun 21, 2020 10:58 am

I haven't heard of akbp before. I tried to do a little searching, but am having a hard time finding resources for this gene. Would you share a link or more information about it? My assumption has been that the climbing sports of rebloomers are just a disruption of the RoKSN gene with the transposon likely excising out in one of the alleles and restoring its function. I saw some 'Nearly Wild' roses that were a mix of rebloomers/one time bloomers at a local store last week (see picture). I won't share who the grower source was, but this source has been selling the mix like this for some time. It is likely easier to take cuttings from the one time blooming version for their own root production or whomever they license to propagate cuttings for them before they grow them on as bareroot in their fields.... In our local landscapes where people have planted 'Nearly Wild' roses in recent years from this grower supply chain, it is sad to see the mix in mass plantings. It is clear that the blooms are the same when the one time bloomers do bloom in spring. This same nursery had done something similarly with 'The Fairy' years ago and wholesale customers tried to get refunds or credits and from what I heard struggled to do so...
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Karl K
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Re: Rebloomers genes

Post: # 71745Post Karl K
Thu Jun 25, 2020 5:54 pm

david zlesak wrote:
Sun Jun 21, 2020 10:58 am
My assumption has been that the climbing sports of rebloomers are just a disruption of the RoKSN gene with the transposon likely excising out in one of the alleles and restoring its function.
Another possibility is silencing/unsilencing of the transposon. That might account for some of the oddities that have been reported in the inheritance of rebloom. For instance, Semeniuk (1971) crossed a true-breeding reblooming Rosa wichuraiana with a true-breeding once-bloomer of the the same species. All the F1 were once-bloomers as expected. One plant was selfed, giving 121 once-bloomers and 37 rebloomers. That works out to 77 to 23, which is pretty close to the theoretical 75:25.

But when he backcrossed the F1 to a rebloomer, he got 517 non-recurrent and 443 rebloomers. That's 54:46. We usually expect the numbers to get better in larger samples.

Then we have the real oddities.

How can 'Mme Norbert Levavasseur' rebloom if it was really raised from Crimson Rambler pollinated by either Gloire des Polyantha or Polyantha Grandiflora? And how could Dr. Van Fleet have trouble getting rebloomers from Mme Norbert when he used pollen from other reblooming parents, but was successful using Mme Norbert pollen on other seed parents? I notice that some European breeders were more successful using Mme Norbert as seed parent.

I just remembered that 'Flower of Fairfield' is a somewhat reblooming sport of Crimson Rambler, though reportedly less vigorous.

And what's up with Kim Rupert not getting reblooming offspring when he crosses Gloire des Rosomanes with Minis?

One of the Brownell roses switches from Copper Glow (once-blooming climber with some repeat) to Orange Everglow, which is less vigorous, but gives more bloom.

Some Hybrid Wichuraianas have a tendency to produce late blooms. I have pictures of François Foucard, my favorite, blooming from late April to early August. ... ucard.html

The inheritance of transposons should be simple, but the expression of the transposon-related trait can be influenced by genetic context and environment. Cuenot (1905) and Castle & Little (1911) studied the inheritance of yellow coat-color in mice. Of course, they had never heard of transposons, so they struggled. C & L came up with very different numbers than Cuenot had. The big difference turned out to be diet. Foods rich in methyl donors increased silencing of the transposon.

Carl Correns studied variegation in Four o'Clocks (Mirabilis jalapa). Pink or yellow varieties crossed with white gave offspring with striped flowers. He found that the white form is a "secretly striped" variety with only a few per cent expressing short, thin stripes. When the relevant transposon is dumped into a new genetic context, the silencing is released and the red stripes come out of hiding. ... poson.html

DeVries (1906) discussed his work with striped Snapdragons (Antirrhinum majus). He used a strain with red stripes on a yellow ground. Through repeated selection for a few generations, he produced one strain in which the great majority of plants bore solid red flowers. A second strain was selected for solid yellow flowers, but was not quite as successful. There were always a few, small red lines remaining. Both strains could be returned to the Florists Ideal of about half red and half yellow in a few generations.

A plant of the ordinary striped sort would occasionally produce a solid red flower. Seeds from this flower (self-pollinated) produced seedlings that had the same tendency to solid color that was found in the strain selected for red. ... riped.html

Webber (906) studied inheritance in a cross between the Black Mexican sweet corn (actually a gift from the Iroquois people of New England) and Stowells Evergreen (white corn).
In the pure Black Mexican: the silks are white or light green, the stamens light green, and the glumes light green, commonly, but occasionally with a few reddish, longitudinal stripes. In the pure Stowells Evergreen the silks range from dark reddish purple to light pink, the stamens are reddish purple and the glumes reddish purple or with marked purplish stripes. It will be noted that the combination of colors here, in comparison with the kernel color, is just the opposite from what would be expected, as the light amber-colored kernels of the Stowells Evergreen would rather be expected to be combined with greenish or light silks, stamens, glumes, etc., and vice versa. It is interesting to note that the cob is white in each case as red-cobbed sorts of sweet corn will not be tolerated in the market, and this character has been bred out of all sweet corn races.

When the mature ears of the fourth generation were harvested and carefully examined, it was found that a peculiar and inexplainable correlation of colors existed. The bluish black kernel color of the Black Mexican was found to be correlated with a green color of silks, glumes and stamens, while the light amber or white color of kernel of the Stowells Evergreen was apparently correlated with the red or purplish color of silks, stamens and glumes. Knowing this correlation, it was possible to examine any one of the 500 ears grown in the fourth generation and tell immediately the general color of the stamens, glumes and silks produced. If an ear had all of the kernels showing a trace of blue from the Black Mexican parent, as in ears 30 and 386, of Plate I, one could be sure that it was developed on a plant having light green silks, stamens and glumes. On the other hand if a portion of the kernels were pure amber or white-colored with no trace of blue as in ears 194 and 471 of Plate I, one could be equally certain that such ears were borne on plants having reddish or purplish silks and purplish stamens and glumes. ... s1906.html

Karl K
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Re: Rebloomers genes

Post: # 71752Post Karl K
Sun Jun 28, 2020 12:41 pm

Transposons may be active or suppressed.
In the Black Mexican sweet corn, the typical color is maintained only so long as the transposon is suppressed. Outcrossing results in variegated seeds and plants.
In Four o'Clocks, the suppressed transposon prevent red stripes/sectors from being expressed. Outcrossing to pink or yellow specimens can unsilence the transposon.
DeVries demonstrated that striped snapdragons can be selected to produce strains that are almost pure yellow (suppressed transposon) or almost pure red (unsuppressed transposon).

Silencing of genes, including heterochromatization, is largely maintained or disrupted through the actions of interfering RNA (RNAi). Here are a few discussions of this matter.

Lippman: RNAi, Transposons (2003) ... n2003.html

Allshire: RNAi, Heterochromatin (2002) ... o2002.html

Madlung & Comai: Stress and Gene Silencing (2004) ... s2004.html

And some more examples of research conducted well before the discovery of transposons that seem to have been waiting for just that.

Davenport: Heredity and Mendel's Law (1907)
Some fowl have five toes instead of the normal four. When a four- and a five-toed fowl are crossed the offspring show no blend, they are either four-toed or five-toed, and neither character dominates. If the extra toe is well developed in the parents a large percentage of the offspring have an extra toe; if the extra toe is poorly developed in the parents a small percentage of the offspring have an extra toe. In this case we have a unit character — extra toe — but no dominance or recessiveness and no evidence of pure germ-cells. The result seems to depend on the relative potency of the four-toed and the five-toed tendency.

Prokofyeva-Belgovskaya: Heterochromatization as a change of chromosome cycle (1947)
B. Conditions of heterochromatization
(1) The percentage of heterochromatization
When a section is in the heterochromatic condition in some nuclei one can hardly find two nuclei in which it has the same degree of heterochromatization. Even two neighbouring nuclei may differ very sharply, the same section being euchromatic in one and completely heterochromatic in the other (Fig. 3).
(7) The influence of parental age on the state of the chromosome section
The condition varies with the age of the parents. Their ageing results in a progressive heterochromatization of the region 20ABC-1AB1 in their progeny. There is reason to believe that ageing causes a progressive heterochromatization of the nuclei of the parents, and that this process affects the condition of the most sensitive chromosome regions in the progeny. The dependence of these regions' state in the progeny upon their condition in parents is also evidenced by the influence of the direction of the cross, and has also been shown by Belgovsky and the author (unpublished) in their study of the relation between the frequency of minute rearrangements and the degree of heterochromatization of a chromosome region.

C. Significance of heterochromatization for character development
Heitz (1928, 1929, 1932, 1933a b, 1934) showed that heterochromatization of any chromosome section shortens its metabolic stage, since it passes through the whole cell cycle as a compact metaphasic body. This suggests that the greater the number of nuclei in which a chromosome section influencing the development of a character is heterochromatic, the more will development occur as if this section had been lost, i.e. the more strongly will a recessive character be expressed in a mosaic strain. ... fyeva.html

Serra: A Cytophysiological Theory of the Gene, Gene Mutation and Position Effect (1949)
According to the hypothesis of an extension of heterochromatin over near-by relocated pieces, the euchromatic regions with the affected genes must show heterochromatization, that is a change of aspect towards heterochromatin. This change is, at least in principle, only one of aspect and not of nature, the euchromatic segment is more or less hindered from its normal functioning but its genes are not lost or mutated, since it is observed that reversion to the primitive location immediately brings about the loss of variegation and the position effect, that is a return to normal gene functioning. These cases of reversion are one of the best proofs against the hypotheses which assume that the genes, or their power of reduplication, are affected.

Conversely, according to the heterochromatization-euchromatization hypothesis it is to be expected that euchromatin also exerts an action, which may be called euchromatization, over adjacent heterochromatin, since it must hinder the heterochromatization—Fig 3. Euchromatic and heterochromatic regions exert, therefore, an interaction and the net result of the two contrary actions depends upon the "force" or potence of the two tendencies. Probably this relative potence depends upon the relative length of the two regions, their more or less pronounced heterochromatic nature and the point of the chromosome in which the relocation takes place. The influence of the relative length of the two regions, euchromatic and heterochromatic, which seems a simple postulate, may be obscured by the nature of the heterochromatic segment and other circumstances, for instance if it includes or not the nucleolar zone (Kaufmann 1943) which seems to be a strong heterochromatization factor. The influence of the other factor, the point where the relocation occurred, is yet more complicated since the true distribution of heterochromatic regions and of zones with heterochromatic tendency in Drosophila salivaries is not known with any degree of accuracy. The chromosome zones where nucleolus-like bodies with a nucleoplasmic aspect are seen must be taken as heterochromatic and the "bulbs" are also probably to range in this category. The incertitudes about this second factor cause that the determination of the amount of heterochromatization to expect in each case be a question to be settled only by actual experiment. When the distribution of the regions with heterochromatization tendency is accurately known, a more or less approximative prevision of the amount of variegation will be possible.

Breese, et al. Somatic selection in perennial ryegrass (1965)
An experiment has shown that the rate of tillering (= asexual reproduction) in perennial ryegrass can be significantly altered by selection within clones. The response to this somatic selection depended on the age of the clone such that response was obtained in young clones raised from seedlings but not in clones with a long history of uninterrupted asexual propagation. The response was also dependent on the genotype of the clone and there was some evidence to suggest that the somatic lability of genotypes was predisposed by a history of adaptation to asexual propagation previous to the sexual cycle. The responses could be attributed to changes in the plasmon and were inferred to be potentially adaptive. The significance of these results in relation to sward dynamics is discussed. ... n1965.html

These examples may be supplemented by others from Rose growing. According to Moreau-Robert (1882), Commandant Beaurepaire began its life as a once-blooming rambler that grew as vigorously as a Banksiae. But with pruning, training, and whatever, the breeder persuaded it to bloom again. With further vegetative selection, the variety eventually became dependably reblooming. ... paire.html

Likewise, the original General Jacqueminot was a once bloomer, or a winter rebloomer, according to Georgia Torrey Drennan (1903, 1912). ... P1903.html ... P1912.html
But Reymond, who inherited the original specimen, selected and selected from the budwood until the variety rebloomed through the season like a Hybrid Tea. ... d1937.html

Vegetative Selection in general fits the RNAi model much better than the "random mutation" hypothesis.

And this RNAi model of gene silencing also supports the old and new idea that young plants, especially those that are at least "a little bit hybridized" make more accommodating parents for difficult crosses.

Oh, and need I mention that a "once blooming" hybrid with fairly abundant late bloom (e.g. François Foucard) is a better bet for breeding rebloomers than another variety of similar ancestry that produces only a few late blooms (François Juranville, Paul Noël, Gardenia). ... ucard.html ... anvil.html ... lnoel.html ... denia.html

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