All A'Twitter x Yatkan

A meeting place for rose breeders.
mntlover
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Re: All A'Twitter x Yatkan

Post: # 70540Post mntlover
Thu Oct 31, 2019 4:34 pm

Joe, thank you for the detailed information. I am looking for at least snow level cane hardiness in zone 5 and eventually zone 4, but that is at the point of attaining good repeat bloom along with beauty and fragrance. A lot will depend (I think) on generations required to reach good repeat bloom and how well cold hardiness can be maintained through those generations. Certainly snowline hardy in zone 3 seems like a great starting point for me in my goals, provided I can work for several generations without becoming much more tender.
Any thoughts on various avenues that could be used to try and accomplish that if it takes a couple more generations to gain the repeat?

By the way, I love that fragrance (thinking Gertude Jeckyl for example, along with many old roses), although I also love Tea rose and a myriad of combinations of scents.
thanks again!

Oh yes, I gathered seed from what I believe to be Rosa woodsi this fall when camping. I also got seed from a rose I found camping up in the North Cascades that was at pretty good elevation, not sure what it was, but figured it might be pretty hardy. Anyone experience with germinating seed from Rosa Woodsi?
Duane

jbergeson
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Re: All A'Twitter x Yatkan

Post: # 70548Post jbergeson
Thu Oct 31, 2019 10:29 pm

It is likely that your R. woodsii seed could benefit from a warm stratification period prior to the cold stratification.

If you're in zone 5 that should make your work easier, because the once-blooming seedlings in the first generation of a species-modern cross should be able to have enough live wood to bloom. Then you cross the best of them with another rebloomer and select for juvenile bloom in that F2 generation. In theory, about one in six of the (modern x species) x modern seedlings should bloom (assuming tetraploids). If working with a diploid species, it should be easier to recover rebloom but also the species' influence will be diluted more quickly.

To be realistic... modern x species cross made in 2020, F1's germinate spring 2021, F1's bloom in 2023 and the best are crossed with moderns immediately (in both directions to maximize chances of success). F2's germinate in 2024. About 1 in 6 of them bloom that spring (juvenile bloom is a reliable predictor of remontancy) and are your first reblooming seedlings with 25% species blood. Maybe your F1's could bloom in 2022 if you have a longer growing season.

Plazbo
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Re: All A'Twitter x Yatkan

Post: # 70550Post Plazbo
Fri Nov 01, 2019 3:24 am

jbergeson wrote:
Thu Oct 31, 2019 10:29 pm
If you're in zone 5 that should make your work easier, because the once-blooming seedlings in the first generation of a species-modern cross should be able to have enough live wood to bloom. Then you cross the best of them with another rebloomer and select for juvenile bloom in that F2 generation. In theory, about one in six of the (modern x species) x modern seedlings should bloom (assuming tetraploids). If working with a diploid species, it should be easier to recover rebloom but also the species' influence will be diluted more quickly.
The other option is sib/selfing the F1 for a 1 in 36 juvenile bloom in the F2 (compared to 1 in 6)

Sure the odds are low, you'll get only approx 27 out of 1000 so would need to harvest a lot of seed but you'd be able to cull very quickly for juvenile bloom so space shouldnt be a huge issue and you'd retain more of the species which is possibly a better breeder/bridge for whatever you're hoping to get from the species.

jbergeson
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Re: All A'Twitter x Yatkan

Post: # 70553Post jbergeson
Fri Nov 01, 2019 1:59 pm

Good point, Plaz.

I'm trying some outdoor seed plots this year to plant larger quantities of OP seed from the aforementioned modern-species F1's, planning to scout for those 27 out of 1000.

Plazbo
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Re: All A'Twitter x Yatkan

Post: # 70554Post Plazbo
Sat Nov 02, 2019 1:49 am

It's something that I'm doing myself. Even though the eventual plan is to be mostly diploid there's a lot of traits from higher ploidies that I'm hoping to move down to diploid which are often attached to once bloomers or older classes without juvenile bloom. Making triploids that are once blooming (and potentially sterile without being able to determine for years) is a space commitment that I don't have the luxury of. So need to maintain the traits I'm looking for and acquire juvenile blooming, maintaining the traits for the most part requires not moving too far away from the source too quickly as the genes involved seem to generally be quantitative in behaviour....so a lot of sib/selfing F1 is stacking those two goals for the tiny fraction of juvenile bloom and potentially more of the once bloomers other traits than if crossing with a second modern.

The more fun one I'm working on and has unknown (but likely far worse) odds is Rubiginosa x Modern (thornless, because why not). Based on the results of someone with Canina X Spinosissima and the F1 being the expected mostly canina like in appearance but the F2 being an array of ploidies as the meiosis broke down. In theory juvenile (tetra or dip) rebloomer could be possible in the F2 without diluting the foliage scent genes too much, just may take something crazy like a million seedlings to find (hurray for 25+ seeds a hip...)....impossible odds here I come. Have already seen some odd results from Lord Penzance selfs that look mostly spin (and have the spin die back, dead wood grossness) rather than rubiginosa so that's encouraging (to me).

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