Author Topic: Brambleberry crosses and growouts  (Read 378 times)

gmuller

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Brambleberry crosses and growouts
« on: 2021-12-13, 08:59:30 PM »
I know next to nothing about breeding berries, but while harvesting my sylvanberries today, I really would like to get a luscious dark early fruiting brambleberry without the annoying spines. The earliness of the Sylvan is highly desirable since i don't have to keep watering through the height of summer to get good fruit. I have a thornless blackberry -that isn't - a tayberry, some boysens, and maybe a marionberry, but they all come with spiky defences. I've also got a truely thornless raspberry (unknown provenance), which is I think a floricane variety - it hasn't really produced much/any fruit this year due perhaps to last year's dry spring.

So to a couple of questions:
what might i get out of seed-grown offspring from any of these lines (without intentional crossing)? I assume they are going to heterozygous for many traits since they are vegetatively propagated. I could just chuck some in a seed tray but they will require considerable nursing to survive summer, and my record is not good.

How might /i encourage synchronous flowering next year (or over winter if i grow under lights) to perform some intentional crosses to the truely thornless raspberry? could a cutting be induced to flower over winter under lights?
G

J Hunch

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Re: Brambleberry crosses and growouts
« Reply #1 on: 2021-12-22, 03:41:32 PM »
The pursuit of new thornless bramble varieties is noble and worthwhile. A lot of the existing ones are pretty lacking when it comes to vigor and flavor.

This thread on rubus hybrids has some great info, in case you haven't already seen it:

http://opensourceplantbreeding.org/forum/index.php?topic=528.0

Living Mudflower has also done a lot of work with thornless brambles: http://living-mudflower.blogspot.com/search?q=thornless I think they sometimes distribute germplasm to others in Australia.

Genetic thornlessness is recessive, I believe. If you wanted to get new thornless hybrids from what you have, I'd let everything cross as it will and grow out seeds from your thornless plants. Any thorny offspring of a thornless plant indicates a cross. Any selfed offspring of those thorny hybrids will have a chance of being thornless (25% if it's only one gene, but might be lower if it's more complicated).

Some of your thorny brambles might have a thornless parent. Any thorny varieties like this should also throw thornless offspring from selfing.

Brambles can have different ploidies, though, which can cause compatibility issues. I've tried to look into the likely parentage of the varieties you named to see which are compatible/have thornless ancestry:

silvan blackberries - ORUS 742 (Pacific x Boysen) x Marion. all thorny. hexaploid
thornless blackberry - parentage and ploidy varies depending on variety
boysenberry - dewberry x loganberry. all thorny. septaploid?
marionberry - chehalem (santiam x himalayan) x olallie. all thorny. hexaploid
thornless raspberry - parentage and ploidy varies depending on variety

Looks like you'd probably have to grow out two generations to get new thornless hybrids from the plants that you have, and depending on which thornless varieties you have, they may or may not be compatible with your thorny brambles. You'd probably get segregation back towards parent traits for any of the varieties listed. The boysenberry might show some red-fruited offspring from the loganberry parentage, for example.

No idea about encouraging synchronous flowering, though. Crossing rates should be high for anything flowering at the same time. You might try saving pollen from the earlier variety if you're having trouble getting the timing to line up. This technique is for daffodils, but it might work for rubus: https://daffnet.org/2013/03/pollen-questions/#comment-15053

gmuller

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Re: Brambleberry crosses and growouts
« Reply #2 on: 2022-01-03, 11:31:36 PM »
thanks so much for the detailed reply
I think i will try a few growouts.
Really good to know about the recessive nature of thornlessness - gives me a rough plan of how to proceed.

I will check out that thread - clearly my search skills leave something to be desired :-)
Sorry for the delay in replying - Christmas commitments just go on and on...
G

reed

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Re: Brambleberry crosses and growouts
« Reply #3 on: 2022-01-04, 09:56:12 AM »
I know this won't help much but the biggest blackberry I've ever seen came up volunteer along the edge of my yard several years back. I think it might have been a cross between a wild one and some of my thornless types. It had giant berries of the most delicious flavor and giant vines. Canes were an inch, (25mm) or more diameter at the base and grew straight up taller than me. Unfortunately, it also had the most ferocious thorns I've ever seen. I used a fishing pole with a hook fixed on the end to pull the canes down to where I could reach them and could only safely get the ones on the very tip. It was also very aggressive and kept spreading into the yard itself, ended up having to burn it out to keep it from taking over the world.