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Specific Families and Genera => Iris => Topic started by: PeterT on January 03, 2011, 11:41:52 PM

Title: Forced Germination - preparing onco seed
Post by: PeterT on January 03, 2011, 11:41:52 PM
FORCED GERMINATION
I started soaking onco seeds on boxing day and cutting them the day after, about a third have started to germinate in the warm without even being chilled, I took some pictures of the procedure. The seeds were soaked for 24 + hours with some detergent and chlorine (very dilute).
Then I wiped the sink with bleach and put some chlorine solution in it. I work in a baisin in the sink. It has water and a 'milton' sterilising tablet in it, also a razor blade. Each lot of seed is put in the basin with it's lable, and I scrape the cover off the pointed end of the seeds where the aril sits, then I cut off the tip of the seed to open the hole where the embryo emerges from. The cut seeds are put in bags with perlite and a little water,  in the warm for a week then in the fridge for a month unless they already start to germinate. I decided I had not cut enough off this seed and cut a second slice which is visible on the blade. The hole in the slice is shows quite well.
Title: Re: Forced Germination - preparing onco seed
Post by: PeterT on January 03, 2011, 11:55:22 PM
A better picture of the second slice off a seed. sometimes it is difficult to decide how much to cut.
and a picture of the seeds in their bag after cutting.
Title: Re: Forced Germination - preparing onco seed
Post by: Regelian on January 04, 2011, 08:30:32 AM
Peter,

great series of fotos.  You've really captured the procedure. (mind you, I use a scalpel knife, double edge razors are not only more difficult and dangerous, but almost impossible to find these days!) The shot with the little hole into the endosperm is absolutely spot on.  I always try to get this 'look', as I find less doesn't seem to trigger germination in many species, although AB hybrids appear to be less fussy.

I'm amazed you had such fast germination on some.  What seed germinated so quickly?  I've just started soaking my seed yesterday.  Today and tomorrow I'll be doing some slicing and dicing.  Getting just the right amount off the seed has proved important for me.

This is such an exciting event, getting these seeds to spring into life, don't you find.  Off course, there is a bit more to get the flower.

Jamie
Title: Re: Forced Germination - preparing onco seed
Post by: Tom Waters on January 04, 2011, 09:51:14 PM
Excellent photos, Peter--a very nice resource for those wanting to learn this procedure. Where will you be growing the germinated seedlings?
Title: Re: Forced Germination - preparing onco seed
Post by: BULBISSIME on January 04, 2011, 10:08:00 PM
Super Peter  :o
Thank's for sharing this technical pictures, always better than a long text  ;)
we're waiting now for the babies... and the flowers  :)
Title: Re: Forced Germination - preparing onco seed
Post by: Maggi Young on January 04, 2011, 10:16:23 PM
Folks, I've split this most interesting thread off to make it stand out.

 See also here : http://www.srgc.net/forum/index.php?topic=847.0 (http://www.srgc.net/forum/index.php?topic=847.0)
Title: Re: Forced Germination - preparing onco seed
Post by: PeterT on January 04, 2011, 11:12:24 PM
Once one knows a trick and can do it it becomes easy though of course things can go wrong!
Tom I shall grow the seedlings in my kitchen for the first few months. It gets no direct sun  and is quite a cold room. The problem with oncos is how to create good growing conditions for mature plants- I desperately need more space for frames next winter!- any one with space I can use locally??
 The seedlings are extra delicate produced this way, I shall post some pictures of the procedure I use for dealing with them.
Thankyou for the compliments Jamie, Fred, Tom, - Maggie I thought people might be interested in seeing this 'reliable' method of germinating onco seed. I have germinated them tradditionally and it can be done that way.
I think over 50% have started germinating before cold treatment, I feel this is exceptional, I would have expected about 10%. Possiably it's due to not keeping the hot water tank hot all the time -so the temperature has fluctuated. about 2% have developed mould and been discarded, taking pictures probably cost in hygene, so did running out of boiled water for the perlite and hunger.
The species I am germinating include acutiloba forms, paradoxa forms, barnumae forms, ibericas, meda, gatesii and some more southern species too.
I have also cut a few Juno seeds as an experiment and some pogons( junonia and trojana), one lot of trojana has started so far.
 There is no pattern by type of onco as to which species have germinated quickley. nor is there a pattern according to the age of the seed. Some I sowed 5 years ago, and after no germination for three years I gave up and sived the seed out of the compost. It has sat on a table for two years and has now started to germinate. some is this seasons seeds. I have not kept any of it in the refridgerator.
Jaimie, if you don't cut enough off the seed the wound heals over and the scab prevents germination, the scab can be cut off to allow the process to work. I have done so successfully.
Every seed is different and one has to use instinct on how much to cut, but I agree with Jamie that I like to see the hole in the centre of the cut.
Title: Re: Forced Germination - preparing onco seed
Post by: JohnLonsdale on January 05, 2011, 03:19:54 AM
The small white dot you refer to as "the little hole into the endosperm" is actually the embryo.  You need to be careful not to slice off too much of the embryo or you will negatively affect root formation and also risk expelling the embryo.  The increased hydrostatic pressure exerted inside the fully hydrated seed will push it out like a pencil lead.

Best,

John
Title: Re: Forced Germination - preparing onco seed
Post by: Hans A. on January 05, 2011, 04:49:35 PM
Fantastic pics Peter! :o
Thanks for showing the procedure!
Just to keep in mind - there is another very interesting thread about germination Iris where among many other grower Rafa and John show superb pictures about forced germination: http://www.srgc.org.uk/smf/index.php?topic=847.0
Title: Re: Forced Germination - preparing onco seed
Post by: LucS on January 05, 2011, 05:47:40 PM
Peter if I understand you well, you cut of the aril plus a small amount of the seedbody itself ?
Title: Re: Forced Germination - preparing onco seed
Post by: PeterT on January 05, 2011, 06:33:50 PM
Thankyou Hans, you are very kind. Amoung these seeds are the kirkwoodii that you gave me at the species group day two years ago. I shall go back to read the other thread properly.
John,  I had a suspicion that was the case but I make no claim to be a botanist. I'm pleased to learn though. I'm just a gardener who likes the difficult plant as well as the easy ones. I did not know you were on the forum, and pleased to meet you again.
I have just read your post from a little over a year ago and I would concur that the mouldy seeds are in the wettest bags, I have just been adding dry perlite to them. Your article ( in the aril soc journal?) a couple of years ago was very interesting- how have the plants matured? Had I known of your posts I would have modified my techniqe a little as your suggestions are very helpful.

Luc, the aril and seed coat is an obstacle which I scrape off before cutting a slice off the seed.

 In the post I refer to, John suggests the seed coat is a source of (?fungal) infection. The surface of the seed is removed over the tip of the embryo, about the thickness of a piece of paper. too much will kill the embryo as John points out, too little and the wound heals -preventing germination as Jamie mentioned.
I am amazed that now the majority of seeds have started without chilling. 3 years ago when I last did this most of them needed a few weeks in the fridge. I hope it is not because I cut too much? :-\ The first seeds look as if they will be ready for pots by the end of the week
Title: Re: Forced Germination - preparing onco seed
Post by: PeterT on January 05, 2011, 07:39:12 PM
It is interesting to see how much of this information and more that Rafa, Hans, Fred, John and John have provided in the other thread, of which I knew nothing. In 2007 I achieved 180 plants with forced germination on about 200 aril (mostly hybred) seeds. Some are still here but I had more than I knew what to do with!
The ones I am growing this time are mostly species though there are a few of Pat's hybreds, Harold Mathes's, Laurence Ransom's and Sharron McAllisters.
I am working hard on providing space so that these ones are not neglected!
 
One of the less promising looking bags is Iris gatesii x afghanica has any one grown this before? It sounds an amazing combination!
Title: Re: Forced Germination - preparing onco seed
Post by: PeterT on January 07, 2011, 07:27:42 PM
Some pictures of seedlings this evening, I have been lining them up in perlite. Ideally they would be in individual pots but space is at a premium, I am going to give them a little bottom heat and put a little phostrogen in the water. In the one picture of 5 barnumae seeds two have gone mouldy. Several bags that were too damp had most or all seeds rot. I shall definately err on the dry side next time. Also I think the most damaging thing is contact with condensation in the bags so I shall probably bag the seeds sown in pots next time as John suggested
Title: Re: Forced Germination - preparing onco seed
Post by: PeterT on January 07, 2011, 07:31:23 PM
a few more pictures including the placing of the seedlings
Title: Re: Forced Germination - preparing onco seed
Post by: Hans A. on January 17, 2011, 08:31:12 PM
Thanks for your superb pictures, Peter! After seeing your results I think I will try forced germination again.
Title: Re: Forced Germination - preparing onco seed
Post by: David Nicholson on January 17, 2011, 08:44:57 PM
Yes, I'd like to try. The problem, as I've said before, is that I currently have a full set of fingers and I'm pretty certain I would land in the finger deficient department after Stage 1.
Title: Re: Forced Germination - preparing onco seed
Post by: Hans A. on January 17, 2011, 08:51:22 PM
David, better use a scalpel instead of a razor blade - I still have all fingers (I am sure I would not have if I would use razor blades ;))
Title: Re: Forced Germination - preparing onco seed
Post by: PeterT on January 17, 2011, 11:00:56 PM
Thankyou Hans, the wetter bags have had a lot of failures, in total I have lost perhaps 40% of the seeds but fortunately not so many of the more special species. Definately better not to put too much water in the bags! and probably better to put the cut seeds on a dish of perlite in the bags to avoid them touching the wet polythene.
The first green leaves are now showing
Title: Re: Forced Germination - preparing onco seed
Post by: arillady on January 18, 2011, 11:28:19 AM
Peter am I right in thinking you don't have cats or little children nearby????
I must think about preparing my seeds soon for the fridge.
Title: Re: Forced Germination - preparing onco seed
Post by: PeterT on January 18, 2011, 06:08:18 PM
Definately Pat, what a dreadfull thought!
Title: Re: Forced Germination - preparing onco seed
Post by: Janis Ruksans on February 02, 2011, 07:18:30 PM
I'm cutting in same way after soaking of seeds for 24 hours, but after that I saw them in layer of coarse sand and bring to unheated greenhouse. I'm doing so with all onco's, regelia's, juno's and reticulata's.
Janis
Title: Re: Forced Germination - preparing onco seed
Post by: PeterT on February 02, 2011, 09:52:46 PM
do you sterilise the sand Janis? What time of year do you do cut the seeds?
Title: Re: Forced Germination - preparing onco seed
Post by: Janis Ruksans on February 03, 2011, 08:20:11 AM
When I have own collected seeds, I'm not cutting them but sowing immediately after harvesting - they germinates very well. I'm soaking and cutting only seeds received from other people which usually are kept for some time. I'm not sterilizing sand - my sand comes from gravel-pit, it is graded but as coming from quite deep layers, I regard it as sterile.
Janis
Title: Re: Forced Germination - preparing onco seed
Post by: ian mcenery on February 07, 2011, 07:05:41 PM
I am delighted - a few weeks ago I got some seed of Iris acutiloba lineolata, saw this thread and thought I would give Peters method a try even though the thought of chopping the end off seeds seemed counter intuitive. Today I looked in the fridge and low and behold some shoots are appearing :o. I suppose now comes the difficult part
Title: Re: Forced Germination - preparing onco seed
Post by: PeterT on February 07, 2011, 07:13:41 PM
Good luck Ian I got some a bit too wet and they rotted fairly quick  :'( , too dry and they shrivel,
got a few coming along though.
Title: Re: Forced Germination - preparing onco seed
Post by: Janis Ruksans on February 08, 2011, 07:43:54 AM
I am delighted - a few weeks ago I got some seed of Iris acutiloba lineolata, saw this thread and thought I would give Peters method a try even though the thought of chopping the end off seeds seemed counter intuitive. Today I looked in the fridge and low and behold some shoots are appearing :o. I suppose now comes the difficult part

I would take forceps and to sow immediately those seeds where shoots appeared - it is much safer against possible ropt or overdrying.
Janis
Title: Re: Forced Germination - preparing onco seed
Post by: ian mcenery on February 08, 2011, 09:40:29 AM
Good luck Ian I got some a bit too wet and they rotted fairly quick  :'( , too dry and they shrivel,
got a few coming along though.
I am delighted - a few weeks ago I got some seed of Iris acutiloba lineolata, saw this thread and thought I would give Peters method a try even though the thought of chopping the end off seeds seemed counter intuitive. Today I looked in the fridge and low and behold some shoots are appearing :o. I suppose now comes the difficult part

I would take forceps and to sow immediately those seeds where shoots appeared - it is much safer against possible ropt or overdrying.
Janis

Thanks Peter and Janis I will pot them up today
Title: Re: Forced Germination - preparing onco seed
Post by: udo on December 22, 2013, 04:41:57 PM
Peter,
many thanks for your implementation to the sowing of Onco Iris.
Here a three days old plant of Iris schelkownikowii, 25 days after him cut.
My first seedling of this species and this shortly before Christmas. ;D
Title: Re: Forced Germination - preparing onco seed
Post by: PeterT on December 22, 2013, 06:42:25 PM
Happy Christmas Dirk!
Title: Re: Forced Germination - preparing onco seed
Post by: udo on December 22, 2013, 06:47:26 PM
Happy Christmas Dirk!
Many thanks, Peter.
Title: Re: Forced Germination - preparing onco seed
Post by: Yann on December 20, 2014, 01:38:10 PM
Using Rafa's method, here's what i got 2 weeks after cutting the seeds.

[attach=1]
[attach=2]
[attach=3]

3 weeks after cutting the young seedlings are now repotted in a 100% fine grit mix.

[attach=4]
[attach=5]
Title: Forced Germination - preparing onco seed
Post by: ikizzeki on December 20, 2014, 04:30:33 PM
Very nice job, Yann. Do you think, it is easy for beginner?
Title: Re: Forced Germination - preparing onco seed
Post by: PeterT on December 20, 2014, 04:37:47 PM
Using Rafa's method, here's what i got 2 weeks after cutting the seeds.

(Attachment Link)
(Attachment Link)
(Attachment Link)

3 weeks after cutting the young seedlings are now repotted in a 100% fine grit mix.

(Attachment Link)
(Attachment Link)

Very nice Yann. I did not know that this was Raffa's method too. I have not seen him on this thread.
Title: Re: Forced Germination - preparing onco seed
Post by: Yann on December 20, 2014, 04:45:53 PM
I read your post Peter and got advices from Rafa.
Yes it's quiet easy, the hardest was to found a shop that allows me to buy scalpel.

The first batch was a bit tricky with 2 seeds destroyed, but after almost 50 seeds i can say it easier than i thought.

Using this method you can easily win a season of growing.

Thanks to the folks for sharing.
Title: Re: Forced Germination - preparing onco seed
Post by: PeterT on December 20, 2014, 04:49:05 PM
I am glad it worked for you. My experiance is that it does not work so well in Summer, but that it is quite easy.
Title: Re: Forced Germination - preparing onco seed
Post by: Yann on November 29, 2015, 08:04:27 PM
Almost one year passed and here're the babies.
I also used seramis as medium and the results are better than in perlite.
Title: Re: Forced Germination - preparing onco seed
Post by: Maggi Young on December 23, 2015, 08:15:19 PM
Bob Nold  has  sent this  document  of his  work with the Forced method of  Aril Iris Seed Germination

It's a pdf - click here  (http://files.srgc.net/general/ForcedArilIrisGermination.pdf)to download it 

Thank you, Bob!
Title: Re: Forced Germination - preparing onco seed
Post by: penstemon on December 24, 2015, 03:00:26 AM
Sure.
How ironic it is that the seedlings do much better for me when planted out in the garden rather than grown inside.....
Title: Re: Forced Germination - preparing onco seed
Post by: Maggi Young on February 15, 2016, 12:06:47 PM
 I think a new thread, on 'Invitro culture of rescued Oncocyclus embryos'  will make  a fine companion to this one  - see it  here :
  http://www.srgc.net/forum/index.php?topic=14058.0 (http://www.srgc.net/forum/index.php?topic=14058.0)   
Title: Re: Forced Germination - preparing onco seed
Post by: Mini bulb lover on March 15, 2018, 08:55:25 AM
These posts are very helpful! I've never grown Onco irises from seed before. After sourcing some seed (Iris mariae), reading these posts and Bob Nold's forced germination document I decided to give it try.

It's early days but it seems to be working. After soaking the seed for two days (tap water with a drop of dish washing detergent) I cut the seeds on March 1st (start of autumn). The seeds are stored in moist perlite in a zip-lock plastic bag in a dark cupboard.

The first picture was taken March 9th. There had been an outline of the embryo before but this was the first date that it could be seen protruding. The other photos are from March 9th and 13th.
Title: Re: Forced Germination - preparing onco seed
Post by: Mini bulb lover on March 15, 2018, 09:06:48 AM
I have some more Onco seed (Iris kirkwoodiae) to try so I thought I'd share some photos of them being cut today. The top seed in the 3rd photo moved as I sliced so it cut more than I wanted. I'll see how I go.
Title: Re: Forced Germination - preparing onco seed
Post by: Jupiter on June 28, 2018, 11:16:52 PM
Jon, how are your kirkwoodiae seeds looking? Any sign of movement? I'm going to do some soon as well.
Title: Re: Forced Germination - preparing onco seed
Post by: Véronique Macrelle on November 15, 2020, 07:26:17 AM
the 2020 srgc exchange being canceled (hopefully it will resume next year!) I find myself without iris seeds to sow this year.
  your discussion made me want to give it a try. and so my idea was to sort out my pots of iris seedlings from a previous year that did not germinate:
 I thus found 4 beautiful seeds of Iris paradoxa. (I occupy my confined winter Sundays as best I can!)

 I have some questions:

- is it essential to sterilize the seeds and the substrate?
- can we sow directly in a gravel pot? without going through the 'perlite in plastic bag' phase? I have always missed this type of sowing with Trillium or Paeonia: too wet or I handle them too much, eager to see changes ... too curious
Title: Re: Forced Germination - preparing onco seed
Post by: Véronique Macrelle on December 05, 2020, 03:57:23 PM
in fact if it should germinate it does not take long: it's too funny!
 I steam sterilized everything.
 I also cut some on the wrong side because on these old seeds the arill was no longer visible.
 I have one that started in 2 days!
 the others I cut back, and 2 are already starting .. but the end of the root is truncated, so I doubt the result.
 the last one (I had 4) seems to be cut off on the wrong side, it doesn't move



and once we have a germination, what do we do with it?
 hot, cold, fertilizer, artificial light?
 i fat germinated it directly in aquarium gravel, but it can't feed
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