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kazanlik 
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The section caninae is iregular. In the case of Rosa horrida 4+1 chromosome sets. It is a pentaploid rose. One set has 7 chromosomes thus 7x5 = 35; 2n = 35
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Still as clear as mud. If 2n = 35 then n = 17.5. Where are you getting n from? What is 2n supposed to indicate?
I understand that a pentaploid rose with seven chromosomes would give a total of 35. That part is clear. Are you sure you don't mean 5n = 35?
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#2 of 5 posted
21 MAR 21 by
Plazbo
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It's not algebra, it's not meant to balance like math in this case, more of a science short hand.
2n represents somatic number (effectively the number of chromosomes in a cell)
n (or 1n) represents gametic chromosome number (eg sex cells, sperm, egg, pollen, etc)
x represents genomic chromosome number
Look at rosa canina (just because it's the most studied of these types) it's usually written as 2n = 5x = 35
eg this diagram
www.researchgate.net/figure/Diagram-of-canina-meiosis-Dogroses-with-a-pentaploid-somatic-chromosome-number-2n-5x_fig1_49942591
but happens with other things, eg banana 2n = 3x = 33, like
www.researchgate.net/figure/In-situ-hybridization-to-banana-chromosomes-2n-3x-33-stained-blue-A-D-with-the_fig3_6074746
It's confusing because we also see things like 4n for tetraploid or 6n for hexaploid but those a different system, somatic number is written as 2n regardless of ploidy.
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Sounds completely bonkers. :D But ok. I get it now. Thanks for the explanation.
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#4 of 5 posted
21 MAR 21 by
Plazbo
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I agree. I'm sure it made complete sense when it was thought up within the context it was being used, in hindsight probably would have benefitted from a different symbol or something given the overlap that exists now.
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Uneven meiosis is really nutty. Even nuttier in the caninae clan than for wheat breeding. And to top it off, roughly half of the chromosomes do not distribute when the caninae type is the seed parent. This is why most caninae hybrids look a lot like their parent. When a caninae types is the pollen donor, there is generally greater distribution and intermix. So, the pretend breeding math looks something like x = (2 + [2])+1, where [2] is genetically immobile.
So, lets say you use Peace. It would look like (2 + [2]) x 2, which theoretically would create a 4+2. Inversely, if used as seed, then it would look like 2 x 1, which would theoretically create a 2+1. When a basic modern tetraploid is used as seed, the immobile set of caninae chromosomes essentially drop. So if you were to do [Peace x (Caninae x Peace)], the likely result would be a typical tetraploid arrangement of chromosomes.
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A note: In the American Rose Annual 1960 Mr. Percy Wright writes: "I put pollen of Harison's Yellow on Pistil of R. macounii.
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Thank you Kazanlik. Reference added. That is a reversal of the parentage we are listing at the moment. I will correct it tomorrow.
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R. Macounii Rydberg is not the same R. macounii used by Percy Wright. His R.. macounii is interchangeable with R. Rosa woodsii Lindl. subsp. woodsii
See Mordern Roses 10 p. 674.
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Thank you Margit. Corrected.
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The rose I bred, Turandot, says -ARS: Gallica-.
What does that mean?
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#1 of 5 posted
24 SEP 23 by
jedmar
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Where does it say that?
ARS: Gallica would mean that it is classified as a Gallica by the American Rose Society. You haven't registered your rose at the ARS, have you?
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#2 of 5 posted
24 SEP 23 by
kazanlikReply
#3 of 5 posted
24 SEP 23 by
kazanlik
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Surely the entries cannot be controlled from outside?
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#4 of 5 posted
24 SEP 23 by
jedmar
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No, we do not add ARS registration info. Taken this line out.
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#5 of 5 posted
25 SEP 23 by
kazanlik
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Thank you for the reply.
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This year I repeated your crossing. Am curious whether rose hips are produced and remontance is present.
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