Schneezwerg

My seedlings of Schneezwerg, (OP) are segregating for the presence and absence of purple pigment anthocyanin on the hypocotyle, leaf stem and young leaves (please see picture). Schneezwerg is as you know a white flowered cultivar, supposed to be R. rugosa X r. beggeriana



I counted 23 seedling with no anthocyanin and 35 with anthocyanins, but have to check on older plants.

In soybean, anthocyanin on the seedling means purple flower, no anthocyanin implicate white flower.

My questions :

-Is it also true on diploid roses(no anthocyan = white)

-does the observed segregation means that Schneezwerg is heterozygous pink/white, white being dominant (usually, absence of pigment, if no epistasy, is recessiv)

-are the purple seedlings outcrosses ? Vigor is about the same on both.

Our opinion is greatly appreciated

Link: img135.imageshack.us/my.php?image=schneezwerg8jn.jpg

Hi Arnold, Your op seedlings are most likely ALL crosses. Schneezwerg is strongly self-incompatable. Isolated landscape plantings near me produce no hips, but in other locations surrounded by other rugosas and other roses it produces a lot of hips. Your males around your plant I believe are most likely contributing the pigmentation and as the seedlings mature you may get an idea for who the likely dad(s) may be.

Sincerely,

David

Hi David,

Thank you for your very clear answer. I am glad to have so many random crosses, to choose from.

Thanks again.

Arnold

I had to confirm this one before I openned my mouth. The Schneezwergs that I have develope a purple skin over winter similar to Martin Frobisher but they are disguissed by the heavy prickles. It is possible that my Zone 2a has an affect.

Thank you john_P for having checked that on yours Schneezwerg. So, purple pigment is also present in Schneezerg and its production probably induced by some stresses.

Very interesting for me to see that the stalks and young leaves of Schneezwerg’s progenies really vary from green to deep purple.

I have also to confirm the observation posted by Henry Kuska on Wed, Jun 25, 2003 about the weakness of the schneezwerg seedlings.

Mine are just much weaker than my others seedlings and some of them are just dying slowly.

http://www.rosehybridizers.org/forum/message.php?topid=2050#2051

Henry wrote

Many wide rugosa crosses suffer from hybrid breakdown and overall plant weakness. Years ago I crossed rugosas with polyanthas and got lots of seeds and seedlings, but seedlings were weak and only a handful survived long enough to flower. Some survivors were “confused” in flower form like the Grootendorsts and like the Grootendorsts especially prone to cholorosis. Your op seedlings may be crosses with non-rugosa germplasm especially prone to hybrid breakdown. David

In my experience, ‘Schneezwerg’ appears to self-pollinate easily and this might account why seedlings are weak growing. Regardless, because the seeds are small and growth is not vigorous it is difficult to raise seedlings to maturity. Still, because ‘Schneezwerg’ is very cold hardy, disease resistant and has white flowers it can be “painted” with any colour, and therefore is potentially valuable to use in a breeding program.

Thank you David,

most of the neighbourhood of Schneezwerg was indeed all kind of old garden roses and climbers, so it is very possible that it catched a wide range of pollen diversity. Hope one or two pollen-grain will fit him.

Thank you Paul G. Olsen,

I Hope I will get less selfs than you got in your conditions and some nice “painted” progenies from outcrosses.

I like your expression that Scneezwerg can be “painted” with any colors. Rose-breeders are artists aren’t they ?

Kindly

Arnold