Author Topic: Trouble with Yacon true seed germination  (Read 56 times)

Olaf Nurlif

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Trouble with Yacon true seed germination
« on: 2019-05-13, 04:10:02 AM »
Hi!

In 2018 we successfully harvested our first own Yacon seeds.
In Austria, 49 latitude! Sadly I made a mistake and didn't cover the plants on 27th of September when a slight night freeze killed most flowers and leaves.
Well, this year I am prepared better.

We got about 200 viable looking seeds. I used to only slightly press them between my fingers when I ordered seeds from Cultivariable (thank you again btw!) to find empty ones.
I discovered that some seeds look rather mature but if you press really hard they will split and are totally empty or with a tiny endosperm.
So I pressed all 200 seeds that way and got 120 that seemed perfect.

Was that a mistake as well? Only one seed germinated... after about a month, which was suprising.
We sowed in the beginning of February, 60 seeds were carefully scarified with a scalpel (I'm sure I did not hurt them at this step!), 60 were sown non-scarified.
We used standard organic potting/seedling substrate, the same we use for virtually everything.

They were placed on a heat mat and substrate temperature was never below 20 or so, and we kept the substrate rather moist all the time.

Could I have dislodged the embryo with my seed pressing or something? Or do I simply underestimate how long it takes to germinate Yacon seeds?

The seeds I received from Cultivariable also germinated over a period of about 6 months but there was always a "flush" of seedlings after one month and after 8-10 weeks. Then they kinda dripped in slowly and then we usually forgot about them in summer.

I guess I will only select visually and maybe by density in water from now on and be even more careful when scarifying the seeds.
Or should I fluctuate temperatures a bit? Change the Light regime? Let it dry out completely and water again after a week or so?

I don't want to use gibberellic acid at this point, I think that would induce a questionable selection pressure, I think it was hard enough for Bill to get them to set viable seeds (again, thank you...).

Oh, I also guess that I can harvest a few hundred or even thousand seeds if nothing terrible happens. So if any people in Europe (or wherever the import of Yacon seeds is not regulated. Stupid seed import rules, pah.) want some true yacon seeds tell me!

Edit: Changed title from "Trouble with Yacon germination" to clarify that seeds are meant.
« Last Edit: 2019-05-13, 05:07:16 AM by Olaf Nurlif »

bill

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Re: Trouble with Yacon true seed germination
« Reply #1 on: 2019-05-13, 12:34:45 PM »
The amount of germinable seed is pretty low.  I get around 10% germination, but that is after I have floated off about 2/3 of the empty or nearly empty seeds.  The germination rate also varies greatly between clones, so if you have a small number of seed-producing varieties, you just might not have any that produce high germinating seeds.  From 200 mature-looking seeds, I would expect no more than 10 seedlings, probably closer to 5.

I have increased my germination temperature to 90F/33C.  I don't get greater germination, but it is faster.  Most of the seeds germinate in the first month.

Good work getting seeds.  That is the hard part.  Now you just need greater numbers.

Olaf Nurlif

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Re: Trouble with Yacon true seed germination
« Reply #2 on: 2019-05-14, 11:04:15 AM »
Thank you for the reply!
We had about 30 plants of the "standard variety" that circulates in europe and 13 seedlings from your seed.
I had an accident and mixed all the plants last year so I don't know which plants came from your 2016 and which from the 2017 mass cross...

Five plants that germinated in February 2018 flowered in their first year, and two of these early germinated seedlings had the greatest yield among all plants this season...
We also got one with nice yellow-orangey peachy flesh color!
Two of the 13 seedlings did not flower at all but 6 startet to flower (sparsely) in July and were in full bloom visited by honey bees by the end of August.

This year we have the one new seedling from our own seeds and about 30 rhizome propagated plants from the 13 seedlings.
We use rather big rhizome parts because our space is a bit limited but we will have more ground in 2020...
Also I got 4-5 plants of "Morado" (which flowers nicely in our climate as well), "NZ" and "Roja" (I don't know if these latter two flowere here..

Sadly I didn't buy any more seeds from you this year because I thought I would get at least 10 seedlings from our 120 seeds.
Well! As you said, the hard part is done, now I only have to hope for a last fall frost. (Go climate change!)

Edit: I might have won in the Cultivariable Yacon Lottery, one plant (Nr.7, probably from the 2017 mass cross seed) seems to start flowering about 15 days after planting the rhizome in a pot...
We only split the rhizome in two parts with about 100 and 130g and only one of the two plants is setting flower bulbs at this point. I'll report and harvest seeds seperately if she continues to flower and sets seed.
« Last Edit: 2019-05-16, 04:59:16 AM by Olaf Nurlif »