Remontancy

I LOVE the work you are doing Joe. Hopefully reshuffling the genes of your hybrids in future generations will lead to many hardy, healthy, reblooming hybrids with beautiful flowers. Dr. Roger Mitchell a number of years ago (perhaps he still is an RHA member, I haven’t heard from him in awhile) wrote this very nice paper on rebloom in species rose hybrids. http://www.globalsciencebooks.info/Online/GSBOnline/images/0906/FOB_3(SI1)/FOB_3(SI1)46-52o.pdf

Thanks for posting the link to that paper David!

Interesting paper. Thanks David.

Thank you David, I have downloaded it to read so I can digest some of it.

It is commonly stated that the everblooming trait is recessive, and therefore not expressed in the first generation. However, there are some instances where the trait is expressed in the F1, but only in winter.

http://bulbnrose.x10.mx/Roses/breeding/WinterRoses.html

I have to admit that anyone who writes, Rosa wichurana Crépin will have to work harder than usual to get me to take the work seriously. But there is one very important point that should be repeated frequently.

Rosa rugosa does not usually begin to bloom until plants have grown to nearly mature size (Zlesak 2001).”

This is not unique to R. rugosa. Nor is it unique to roses. Garner & Allard (1920) introduced the subject of photoperiodism. They first got together because both of them were studying the mysterious ‘Maryland Mammoth’ tobacco. This strain would grow like any other tobacco until it approached the normal flowering time. While other strains bloomed, MM paused briefly, they resumed its growth.

If the plants were cut down and transplanted into a heated greenhouse, they would come into bloom in the dead of winter. Seedlings started in the same greenhouse would grow until they were 3 feet or so tall, then start blooming.

Please note: they did not start blooming as soon as they produced a few leaves. They could not respond to the inducing (short) photoperiod until they were big enough.

There was some variation in the height at which the seedlings began to bloom, but G & A did not stop to wonder whether the differences were hereditary. They had enough on their plates, at the time, so I hold no grudge.

The same holds true for various fruit trees and grains and … whatever. There is a minimum quantity of growth that must be made before inducing conditions can … induce.

Cutting back the plants cannot get them to hurry up. It only delays them.

Van Mons (1835) discussed a variety of techniques he used to hasten the maturity of fruit trees. A bit of crowding helps, as well as shortening the laterals to encourage the main shoot to grow.

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[quote=“jbergeson, post:1, topic:7344”]
Paul Barden’s words are a tickling echo in my mind: “Some of my most heavily remontant seedlings have not blooomed AT ALL the first season.” However, I have no experiences to match this and I have to assume that most of my seedlings that do not bloom the first year are never going to be remontant.
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In my experience so far, seedlings that do not show any flowering in the first year, remain once bloomers in subsequent years. I hope every year to be convinced of the opposite, unfortunately so far in vain. Even if the predisposition to remontancy is genetically recessive, there should always be an exception to this ‘rule’. Just as occasionally in one or the other seedling some recessive traits appear and lose their masking.

What experiences have you had? I am very interested to hear your comments. Thank you very much!

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I really wish that I had something more interesting/revelatory to say here, but I’m afraid that my experience has been exactly the same as yours and Joe’s. The only odd exception that I can think of was exactly contrary–a seedling that flowered as a juvenile but then failed to flower again for the rest of its first growing season (unfortunately, it didn’t survive to see a second season). It would be interesting to know the background of any non-rugosa seedlings that are heavily remontant but didn’t exhibit juvenile flowering.

Stefan

Just to blab a bit about remontancy.

I have to admit that I’d be upset if Paul’s assertion about non-juvenile bloomers becoming heavily remontant in future seasons turned out to happen more regularly. The ability to sort out non-remontant seedlings at a very young age is critical to a breeding strategy that focuses on incorporating species genetics and recovering remontancy in successive generations.

Remontancy does not appear to be a straight-up recessive trait, because some remontant roses do not pass on remontancy 100% of the time. Prairie Joy is one such rose. I don’t have a percentage in my head, but I’d guess that more than 50% of its seedlings do not rebloom.

Interestingly, I have two instances of Prairie Joy crosses reblooming when they really shouldn’t. It makes me wonder if PJ might have some sort of “occasionally dominant” reblooming genes??? Of course these two instances could be the result of stray pollen grains, so should be taken with a lot of salt, but the two crosses were PJ x (R. carolina x R. centifolia) and PJ x my local native rose. Both seedlings are fully remontant…but shouldn’t be.