WEC- embryo culture, although not formally named at the time, starts being demonstrated in the postings starting Tue Aug 3, 2010.
WEC - Embryo culture (EC) link:
Link: www.rosehybridizers.org/forum/message.php?topid=23111#29671
Stating the obvious, but EC technology is already avaiable, simple, very legal, and is being used as I can see small scale, and even larger scale, as Don Holeman has shown us.
Simple facts.
More casual thoughts:
Small scale random applications of rose EC can also be fun, and used to promote the fun aspect of amateur rose hybridizing, to those individuals who seek this sort of “fun”.
One can take it or leave it…and then go back to it if they so desire some time later on.
The reasons one might try rose EC only have to be justified to one’s self IMO. However this is rather selfish, and also sharing this information rather than just internalizing it can also be quite a lot of fun.
So far in this thread, and from information posted on this forum generally, rose EC has been applied as a system of germinating new rose seedlings for legitimate reasons as diverse as:
1.Research and development in rose hybridizing.
- Germinating otherwise near- impossible-to-germinate rose seed (achene).
3.At least two beginners (I was one) getting started in the rose breeding hobby.
- Even as a total substitute to conventional rose seed (achene) sowing!!
Why not?!
Has anyone studied the type and/or the amount of chemical germination inhibitor within bare bare rose embryos (ie. rose embryos with all pericarp and testa fully extracted)?
That’s a great question George. Here is one by Bo et al.
Achenes from the hybrid tea
Here are some additional, if not obvious, practical considerations for rose EE / EC, I thought I might mention in reply to earlier questions:
It is necessary to build up skill with the EE, and find tools that suit your unique needs and abilities to help get the best strike rates for the EE. This takes time in advance.
Then there is an unknown period of time one has to practice on say OP achenes (ideally OP achenes of a similar size and nature to the intended achenes). By practicing this way, one would aim to get EE strike rates up, so that one can get like 90% or better extraction rates. By this I mean, 90%+ success in getting from achene to fully extracted and undamaged embryo. Be very aware that any hint of damage to the embryo radicle means you best just throw the embryo in the bin. Any hint of squashing the embryo means canning it also.
I’m not intending to discourage potential players from exploring the fun that can be had in trying their hand at EE (e.g for the sake of curiosity or having some random fun), go for it!!
But I feel these are important practical points to bear in mind, in the overall planning…It is this planning ahead and practicing of EE, that is going to take up the majority of time and other precious resources, if one was to embark on serious EE + EC. Doing the EC per se is a piece of cake, it is the EE which is the rate-limiting step in any EE + EC successful combination.
Utilizing the services of a known proficient rose EE practitioner is another obvious alternative, and might prove the best practical solution in some cases.
One would at all costs want to totally avoid a situation where time was invested creating a known cross with near zero achene germinations by sowing, and then discover at the eleventh hour they are not able to extract any excellent embryos due to lack of skill.
Thanks for that information David, it is real interesting to know!
LOL… I sat down and extracted like well over 100 tiny achenes yesterday whilst killing time attending to a very booorring task that required me to “sit there” for a few hours and keep a watchful eye over a problematic situation in the house…a few hours later and there they all were, too many extracted tiny rose seeds sitting in a glass of water.
I just removed their testa this morning after a 24 hour initial soaking… quite gratifying actually.
It goes to show, if one has done enough practice and developed a routine, fairly substantial numbers can be done, but I do stress it takes a lot of time and practice.
Why am I writing this you ask??
Well…lately I have had the opportunity to test out WEC on a much larger scale (like hundreds and hundreds of dry achenes)…and it has meant I can soon provide you with more observations about WEC, and how best to ulitize it, if you do wish to try it.
I am going to wait a few weeks for all the runs to convert to seedlings, and then post here a few interesting observations that might help shed light on how to best ulitize WEC…stay tuned…
Here is why commercial seed raising mix is definitely not a good thing to use for germinating WEC embryos.
Today I discovered to my horror that insect larvae have chewed a lot of the embryos to death, in some of my current larger scale WEC runs!!!
Here is the causative type of larva I discovered after digging around some of the markers where I had sowed WEC embryos which should have germinated by now…I found a few of these larvae wiggling around some of the the chewed embryos:
Here is a tunnel damaged cotyledon of a WEC embryo which I re-sowed thinking it might still germinate despite the larval damage:
Here is one larva on the side of a toothpick for size comparison:
Here are three pictures showing a larva in the process of chewing a WEC embryo:
I recently did hundreds of EE only to have a significant number of failed germiantions due to this larval attack!!!
Can anyone here recommend a suitable germination mix I can use for my last remaining embryos, which are soaking in water for two days now (post testa removal), and which I want to mass sow in the next 24 hours??
If you know that the “larvae” come from the potting medium, not the seeds, bake the potting medium as Don describes, or, my preference, in a pressure cooker for 20 min, moist. Be sure to put it in foil- covered containers probably glass jars, though the 3 lb plastic coffee containers sold in this country will stand autoclaving a couple times. If you don’t loosely cover it, some loose stuff could come out and plug the pressure release on the pressure cooker. That in turn leads to a blow-out of the pressure relief valve and dirt all over the kitchen.
I’m not sure of scale in the photos. Any possibility of nematodes? Or could the larvae be coming from some kind of eggs on the seeds? In which case peroxide might work.
I’ve had troubles with the larvae of fungus gnats killing germinating seeds and very young seedlings. I now sterilize any seed starting medium and use sticky tapes to kill any adult gnats that might be present.
Great photos, George.
Perlite straight up is ok to get your seedlings off and running. I use insulation grade, much more fine than the horticultural and way less expensive. Use a very dilute soluble fertilizer, 10% of the normal concentration or less. Transfer them to potting mix as you put them outdoors and start increasing the fertilizer as they get bigger.
Hi Larry,
If it helps to make an ID, here is one of these troubling critters near a tape measure for sizing up…the scale is 1/16 of an inch for each gap between the lines. What do you think this is???
In real life, if you were to look at one, it is soooo tiny you could no way see it unless you knew where and what to look out for…they are about as fine as the finest of human hair, and extremely difficult to see unless seen against a dark background…they are tiny tiny threads, barely visible to the eye…they could easily be missed!!! They are grossssss, and there are probably thousands of them in the mix, and seemingly concentrating themselves around some of the embryos.
I have no doubt that these critters have caused the damage to some of the live embryos, and have caused some embryo deaths. If I had not seen the tunneling in the otherwise very healthy embryo shown above, I might have thought that they were just eating embryos that had already died from other reasons, but now I am certain this is clearly not the case!!!
Hi terryR,
Thanks for your input. I sure don’t blame you for taking such measures…these rose embryos / seeds / achenes we all sow represent too much valuable work and time to go to such waste!!!
Hi Don,
I love your suggestion about the perlite!!!..I’m gonna use 100% perlite to germinate the remaining batch of water soaking WEC embryos. As a matter of fact, I have never used perlite, this sure has convinced me to get on with it…so off to the local nursery tomorrow/ASAP!!!
Yep it is fun to take and post these pictures, but it is very sad for me to see soooo many hours of work gone to waste, as dinner for these grossssss critters!!!
George, I have discovered fungus gnat larvae directly in the stems of keeled over seedlings and of course as in your photos, in the seeds themselves. I also hybridize clematis and the bugger worms have been a problem with these slow emerging and developing seeds and seedlings. I now take whatever precautions I can to deter the pests. I don
Hi TerryR,
I hear what you say, thank you. I am worried that these may also attack the few embryo/seedlings which did manage to actually sprout in the same containers of seed raising mix…those few seedlings must be either real sturdy rose seedlings or else real lucky ones!!! I worry that these too may suffer a root attack from these sneaky things hidden in the mix in sooooo many numbers…I suppose there is nothing much I can do to prevent that happening, short of removing those seedlings, and risk damage from such a move (I’ll skip that idea and cross fingers instead).
I can see now why germination rates can be so variable, from run to run…it is not always to do with the seed or embryos being “bad/non-viable”!
…and it would have to be the case that the embryos this time are actually very precious, not just any old OP stuff!!!..yes “Murphy’s Law” I hear you say!
LOL…these worm-like things are very smart, their real-time behavior has to be explained here!!!
It took me like 70+ photos to actually get one to reveal like at least 70% of its true length to the webcam lens…they are very very camera/light phobic critters!!! They wrap themselves around the embryos (or bits of tiny debris) and do not let go… and look/behave every bit like microscopic serpents LOL!!! They have an incredible ability to shift debris much greater than their own weight/size and have real tight jaws which hang on to what they’ve got real tight!!
I wish I could bother to join You Tube, and upload a video on their behavior, just to make ya’all laugh out loud.
I photographed like 5 or more of them and the one shown immediately above here (against the tape measure), was the only one that revealed itself enough to make a meaningful picture of scale against the tape measure. They hid either inside crevices in the small bits of debris they clung onto, or behind and within such debris…most of the time I was not able to actually see them as they were playing this hide and seek game!!!
They are disgusting… I think Larry and you might be right guessing they may be some kind of worm rather than an insect larva as I originally thought, but my abilities in ID of such type of critters large and small is zilch!!!
WEC UPDATES:
As I wrote recently, for the first time I have now had the marvelous opportunity to put WEC to the test on hundreds of achenes, both tiny diploid achenes as well as tetraploid.
This has meant that for the first time, I have had to process many embryos in one glass of water each go…this is a new ball game compared to just doing one or two or ten each go…it has meant that new procedures have had to be thought out, and some changes have had to be made, to make the whole WEC operation practical as well as optimal.
The main change I have decided to make is to not wait for all the faster sprouters to start extending their radicles and sow them preferentially (as advised at the start of this whole thread)…this is just not practical to do when you have like 50-100+ embryos soaking in a single glass of water!!! Also, there is no easy answer as to how long is too long for water soaking the embryos…in the same batch of embryos, a few will lengthen their radicles in a certain number of days, whilst others in the same group/cross will have drowned in that time (they start to mold, go a tan color or even develop pink bands!!!). I feel embryos are all individuals, and are not predictable in their reactions to the water soak / imbibition.
Sooooooo, with all this in mind, I have decided that for myself, I’ll extract all the seeds from their woody pericarp coverings on the first day, then let the seeds with their papery coverings (testa) soak overnight, and then remove the testa on the second day. Then I will leave the embryos lacking their papery testa to soak in tap water/imbibe for a further 48/72 hours. After that 48-72 hours, I will then mass-sow all of them, as though I was sowing achenes, regardless of their appearance.
I am wondering that such modifications to WEC could perhaps impart some of the following benefits:
- I hypothesize that brittle embryos with fewer/depleted available resources (eg. derived from very dry-stored achenes) will be far less likely to drown in the water imbibition if it is 2-3 days long.
2.There is only ONE transfer from water to germinating medium (compared to multiple transfers over may days) which saves a huge amount of time, and greatly minimizes collateral damage to surrounding embryos in the glass of water.
- None will likely have developed a long rootlet which can be prone to breakage in transfer from water to sowing medium.
As you can see, I am catching the “bug” again for embryo culture…I love not having to wait months and months to get germinations…and my EE are getting a whole lot faster these days!
Here is a picture of some of the 100+ diploid embryos I am about to mass-sow this morning which have been soaking in water for 72 hours…you can see that on the top right of the image, there is a fast sprouter after this three days of soaking…sometimes there will be even longer rootlets developed in three days for ulta-fast sprouters!!!
I would not want to be sowing fast sprouting embryos with much more length of radicle than shown in the embryo at the right hand corner of the image below, it could easily snap…(hence my 2-3 day soaking limit).
Remember, these images are many times magnified, in reality these rootlets are nothing more than tiny very delicate threads!!
I would especially like to thank Don Holeman, for all the tremendous inspiration his work gives those of us dabbling with rose embryos…I know there are a few of us in RHA now playing with rose embryos.
I certainly have never done any formal reading on the subject of EE/EC, let alone create a complete manual… but somehow I had randomly dabbled in EE/EC since a few years ago, long before I came to know about RHA, and all you guys/gals…that is why WEC came about, it has nothing to do with wanting to be deliberately “different” per se…but in the end, we are all different and we each develop our own happy ways, and methods, and hopefully we get some results and can share these with eachother, especially here on this great forum.
I am sure if I had started EE/EC at the time Don’s manual came out, I would have just followed it, step by step…
BUT… in my case…“It is hard to teach an old dog new tricks” LOL!!!
I tried to get the very fine perlite (insulation grade) but could not find any…so as I was running out of time, and just for curiosity sake, I got the usual coarse horticultural perlite anyway. I had never handled the stuff, and wanted to at least get some to play with.
I found sowing these little diploid embryos into the perlite very hard, as there was next to no contrast between embryo and perlite. Even though I pre-wetted the perlite, I got worried it may all dry out even with twice daily misting onto its surface, so I put the pot with the perlite onto a saucer of water so it can hopefully maintain adequate moisture…is this over-reacting??
So I panicked a little, and sowed the remaining half of these embryos back into the commercial seed raising mix, only this time I also remembered what you suggested Larry, and did the next best thing and ran boiling water through the seed raising mix twice, and let it all cool down before sowing the embryos into it.
Sowing ivory/white embryos against dark seed raising mix is infinitely easier to do, if there is a choice in the matter!!!
I hope running boiling water eliminates most of the nasty infestations in the mix, I know it is not as near as effective as the baking/pressure cooking that was suggested, but it might be ok…time will tell.
Thanks again all for your wonderful help!!
Hi George,
I don’t think you’re overreacting by placing the pot in a water saucer, but even then you may find that it doesn’t stay moist enough because the coarse medium doesn’t wick very well. Another even bigger problem is that there likely won’t be adequate direct contact between your embryo/seedling and the horticultural-grade Perlite, so it probably won’t be suitable for that purpose. I have germinated much larger seeds than roses (with much larger radicles, obviously) in the stuff in order to prevent rotting, but then quickly transitioned them to a more conventional mix when they had sprouted. Your best bet for keeping it moist for the moment will be to place it inside of a sealed plastic bag or something similar. That alone will keep the Perlite from losing its moisture to the surrounding air. Personally, I think I would transfer them back into your other mix as soon as possible.
I hope that you have good luck with the mix treated with boiling water! Various and sundry worms and larvae can wreak such havoc with rose seeds. I’m looking forward to playing around with your method some time.
Stefan
Hi Stefan, I appreciate your help, thank you!