Selfings of Hulthemia Hybrids to increase blotch gene sets


As we know from Jim Sprouls thoughts that are all derived from well done experiences and experiments, the hulthemia blotch should be influenced in existence form and colouring by several genes on perhaps different chromosomes of the rose.

So selfings might be a good idea as it seems, at least froim time to time, to increase the number of the different proposed blotch gene sets, that are needed for the expression of a good and clear blotch.

I did some selfings (just like normal pollinations, only done with pollen from the same plant!) with Alissar from Harkness last year and there is now one seedling with its first bloom yesterday, that seems to have a blotch - and perhaps some of the needed genes are increased in number in this crossing.

What do you think about such a practice?

OK its not that cool - but might be effective in my eyes!



PS: Here it is, my first blotched seedling (not too difficult to achieve, first germinating and flowering seedling out of abt. 70 seeds that brought me 10 seedlings so far)! :wink:


Hi Arno,

It looks like you have a great blotch! I think that you will be very pleased at how large it gets on a more mature plant.


Jim Sproul

Hi Jim,

thanks! Yes it will be interesting, too, to see if the blotch genes are really concentrated in such selfings.

I think it will be indirectly visible in the rates of blotch-seedlings that will occur in offspring!

I can compare that to Alissar seedlings directly, if I do same crossings on both plants, later.



Hi Arno,

Regarding “selfing”, I have done a lot of planting of OP Hulthemia hybrids seeds. There will be an occasional seedling that is better than the parent, but that is not a very frequent event. That is partly what has made me think that there might be more than one gene responsible for the blotch. Perhaps one for the presence of a blotch - probably a dominant gene; one for intensity - possibly a recessive gene; and one for blotch shape.

It might be that there really is only one gene and the other presentations may have something to do with the interaction of the Hulthemia blotch gene with various rose genes.

In any case, there is a huge variability in blotch size, intensity, color, and heat stability.

Jim Sproul

Hi Jim!

Very good summary - I think its exactly the situation as you describe it: the gene interaction might also play a role … .

But: Its not easy to find out that with the Tetraploids, what you describe, I think. There could be additionally some gene dosis effects too, as you have it for, e.g. occuring dwarfism when selfing tetraploid roses. Or the loss of resistancy in tetraploid (colchicine!) rugosas, that were resistant as diploids.

To really find out more definite info on that one should create diploid breeding lines with well known diploid partners.

But the only Hulthemia I know that is diploid and fertile is Tigris.

I did few Tigris pollinations this year, but most of them already have failed. So at least I will not know more about that, next year. :wink:

A hard job, really. … But thats the fun.



I know nothing about blotch genes as such, but look at the more general genetics problem. Interfering RNA (RNAi) was discovered in petunias when a group tried to introduce a transgene to increase the color intensity. It was just an extra copy of the gene already present, not something from outer space. But instead of getting more color they got less, in all kinds of interesting patterns. It seems they had triggered a system that responds to virus infection, which tries to silence genes that are making too much RNA.

That’s a really abbreviated, sketchy summary, but the point is, sometimes more is less.

My own example is selfing the offspring of Carefree Beauty x General Jaq. The pollen parent is a dark red. The offspring range all over the place in shades of pink, but none as dark as Gen Jaq. None of the selfs of the half dozen best, medium red offspring, come close to it. Simple genetics would suggest that some should.

Roses in the line including Gen Jaq, Crimson glory and other very deep reds must have not just a good dosage of anthycyanin production, but regulatory genes that let it keep on piling up to several % by weight in the petals. It is a delicate balance of multiple genes to get this to happen. Overdo one and you may get the RNAi suppression.

Does this really happen? We don’t know for roses, but it has been documented in a lot of plant species for a lot of genes. There are whole networks of regulatory RNA molecules, which go by various names but basically are 10-30 bases long, and are produced from bigger molecules by enzymes with names like Dicer, which cuts the big into little. The little ones bind to messages to turn them off usually. That in turn switches off or on, some other paths. The principle is to keep things in balance.

Part of the challenge faced by people who engineered the blue rose, was this sort of thing when they tried simple tricks for getting over-expression of certain genes in roses. If they know exactly what happened, they don’t say, but they had to resort to alternate strategies.

So there may be limits to blotch intensity related to the color of the rest of the petal for instance. And we know next to nothing about the developmental stages of the petal and how many possible pigment expression patterns there can be. Nor how they can be combined. There must be rules in the genes, but we don’t know them yet.

Hi Larry!

your comment shows the intellectual challenge behind the beauty of the hulthemia blotch, I think.

Your comparing of the petunia experiments with the mostly tetraploid hulthemia blotch crosses is a good idea, because it gives a view on what is possible according to flower colour expression via epigenetic phenomena. Speaking of roses, I think these phenomena will occure much more in tetraploids than in diploids, because of the higher possibility in gene-interferring RNAs and also gene and master gene products.

Diploid breeding lines so could help to avoid too much of that odd cool new stuff along finding out what mainly determines the blotch normally.



So for the title of the thread “Selfings of Hulthemia Hybrids to increase blotch gene sets” I can only agree to Larry and so we have to wait for more seedlings and data, until it is more clear, if the “increasing of the numbers of blotch gene sets” is in fact really helpful or not.



Nice, Arno! How is Allisar as a plant? Do you grow the other two new Harkness hulthemia hybrids too? Are they good as garden plants?


Hi Rob!

Alissar is pretty good as a plant, with good health.

Grows like a floribunda, with semidouble flowers.




And the plant of Persian Mystery is a bit smaller and more dense in its habitus so far, has got more double flowers but a blotch that is of a very dark violet colour.

I like the flower-shapes of that plant.

It is not that resistant / tolerant to blackspot compared with Alissar, it seems, but healthy enough to get through without funghicides.



… Foto below …


Hi Arno,

These are nice photos. I like the plant appearance of ‘Allisar’ and the blotch intensity of ‘Persian Mystery’.

Playing with the blotch gives 1 more variable to challenge the breeder with getting all (or most of) the good traits into one package!

On another note, do you still have access to Hulthemia persica seeds? It would be fun to see how it grows in our climate. We must have a very similar climate to its normal habitat.

Jim Sproul

Hi Jim!

The plants are still alive. But they flower not very well and so I had no seeds for 2 Years, except 1 from one pollinated flower in 2008: It gave a F1 hybrid seedling in Winter 2008/2009, but it died after germinating.

I try to get flowers in 2011, if there are more than three flowers I will pollinate persica x persica and will get fresh seed.



I agree that selfing could be helpful. What would also be useful would be to keep breeding something like Tigris on the diploid level only for breeding into wichurana-type landscape roses. Not only is it a great source of diploid yellow with some repeat genes, but it is also a source of possible eye zones :slight_smile:

I grow Persian Mystery. Here its color is a nice curious blend of the shade of purple Arno’s picture shows with some coral that fade nicely to lilac. The bloch is dark purple.

Nice flowers and compact plant rather desease free in its first year.

Another hypothesis about bloch genetical control would be that bloch is basic petal color which is more or less inhibited elsewhere.

As it is with handpainted roses border that may partly discolor or not. Just as illustrated in Picasso pictures.

Hi Jadae!

With wichuranas the yellow would fade in every case, but that if you look at “Euphorbia / Euphoria” from Interplant - the leavelets look similar to wichurana style … I think others thought the same!

Hi Pierre!

The colour is truely a bit variable, I have seen meanwhile.

Your thoughts on the blotch are interesting, but one thing: Rosa persica is related to the spinosissima section of roses.

There is no such a dark red in full petal colours around … but several shades and tones of yellow!

So: Which one should be the true typical background colour of petals of rosa Persica, red or yellow?



By the way: I did few Alissar x Persian Mystery crosses.

OK that is nothing spectacular (Harkness does that anyway in every direction since years I guess), but I will see if the blotch output in offspring is increased or if the blotch is whiped away by epigenetic or gene dose effects.



PS: someone out there means he has got Xerxes!

From … California? Is that possible, I mean than you all would now that, am I right?

What does that mean, is the plant still existing?

Would be a real nice partner for selfings and crossings with other hulthemias.

Here is the link to the mentioned hulthemia blog with possible “Xerxes”:


I’m assuming ‘Euphrates’ is diploid. The blotch in it is very pronounced. This is my one taken last year (I’ve shown this photo here before… the blotch is huge and very well defined):

If the blotch is dominant as Jim suspects, and ‘Euphrates’ would back this up because its pollen parent was ‘Fairy Changeling’ (also a diploid poly.) which would make ‘Euphrates’ a heterozygote that expresses the blotch, then selfing ‘Euphrates’ would make the blotch huge if homozygotes could be made… but its fertility is very, very low. Maybe it would be better to work with very fertile diploid seed parents with these early diploid hybrids, to reduce this dose effect in heterozygotes (50:50 chance of getting a blotch if the trait is a simple Mendelian one) and improve fertility and then selfing these blotched hets. to try for homozygous diploids. My theory is that if the size of the blotch is in part determined by the degree of homozygosity, then heterozygotes in diploids, like ‘Euphrates’, should still show very good blotch size (also because the number of other polygenes are reduced) and maybe it would be easier to improve blotch size if diploid hybrids were developed. This is the main reason I bought ‘Trier’ this winter… to put ‘Euphrates’ onto it (because ‘Euphrates’ should also carry a single remontancy gene). Very fertile diploid minis might be a good way to go too. I have ‘Altissimo’ x ‘Euphrates’ seeds in the fridge right now (they’ve been in 8 weeks now… should be ready to sow but I’m going to give them an extra long cold spell because ‘Altissimo’ seeds are such a *$#@&! to germinate), but this will give me triploids and no guarantee of any blotch at all if ‘Euphrates’ is a het.

Hi Simon!

“homozygous diploids” as an aim.

Thats what I meant, too (and jadae also I think) would be perfect to study the genetical inheritance of the blotch!