Author Topic: Rhubarb breeding  (Read 2910 times)

Johann Kuntz

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Re: Rhubarb breeding
« Reply #45 on: 2021-03-10, 04:56:19 AM »
I grew out a batch of rhubarb seedlings last year.  When planted in fertile soil they put on size pretty quickly and while last year some had green leaf petioles and a few had red, they're all appearing to have red leaf petioles now going into their second year.  One that I had set aside as having redder leaf petioles than the rest last year is looking extra red so far this year with even the red extending into the leaf blade on the unfurling leaves (though I still expect they will present as green once fully unfurled).  I'm looking forward to checking to see if the leaf petioles will end up being red to the core on that one.  Another seedling consistently expressed a cupped leaf shape last year.  That one also had pretty good vigor.  It'll be interesting to see if that continues this year. 

Overall, I found quite a worthwhile amount of variation among seedlings even though they were all grown from the same seed source.  It definitely seems that interesting new varieties could be selected by anyone who is seriously interested in doing so. 

nathanp

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Re: Rhubarb breeding
« Reply #46 on: 2021-05-16, 03:53:18 PM »
Thanks for posting your experiences, Johann.  Very helpful to hear your results.

I have been searching online for articles or references for anything that mentions whether any of the other Rheum species (besides R. rharbarum) have edible stalks.  Mostly, the answer is the other species are described as poisonous, with some medicinal uses.  But the stalk/stem is never mentioned.  Leaves have oxalic acid, blah blah blah.  Roots are used as a diuretic, blah blah blah.  One problem is most of the papers are not about edibility, they are about either chemical or antiviral properties, and edibility of the stalks may only be mentioned as an aside.

Well, I finally found one and hopefully more with references.
Quote
It is grown as a vegetable for harvest of its edible leaf stalks, Chinese rhubarb is primarily grown as an ornamental for enjoyment of its huge rounded leaves and feathery plumes of summer flowers and a medicinal plant
https://www.tandfonline.com/doi/full/10.1080/23802359.2019.1681319#  Characterisation of the complete chloroplast genome of an endemic herb plant species, Rheum palmatum (Polygonaceae) in China
Xiu-Hang Zhang, Yu Long, Qing-Hua Yu, Tianyi Cao, Xin-Xin Chen.

I suspect several of the other species may have edible stalks as well, despite the commonly spread 'knowledge' to the contrary.

Here is another interesting paper on some of the research being done on compounds found in Rhubarb or of extracts.  Anti-cancer and anti-virals, with specific mentions of more than a few viruses.
 
https://link.springer.com/article/10.1007/s12272-013-0325-x
Antiviral activity of Rheum palmatum methanol extract and chrysophanol against Japanese encephalitis virus

This year I did receive 7 of the 10 requested accessions from the USDA genebank.  Due to covid, they were unable to dig them or send them last year, so I am grateful for the germplasm this year.  Six of them are 4x R. rharbarum, one is 2x R. palmatum.  I will be interested to see if the 2x plant is able to pollinate itself, among other things to watch.  They are planted in two adjacent diamonds, along with one previous variety that I had.  I am not sure which one I have, but it is not Victoria, because it has a much redder stem. 

I will hopefully be planting out seedings in 2022 out of seeds from this year.

Johann Kuntz

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Re: Rhubarb breeding
« Reply #47 on: 2021-05-17, 11:04:25 PM »
Look up Rheum australe.  It's supposed to be pretty good.  I failed with my first attempt to germinate seeds and killed the few sprouts I got, but now on my second attempt I've got a lot of healthy seedlings of this species.  I'm looking forward to widdling down the seedlings to select the most productive clones.

I've also got four seedlings of R. palmatum which I plan to evaluate for edibility.  So far one is really standing out as leading in growth vigor.