A meeting place for rose breeders.
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/Onli ... 46-52o.pdf
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.
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.david zlesak wrote: ↑Mon Aug 27, 2018 9:33 amI 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/Onli ... 46-52o.pdf
"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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