I got fed up waiting weeks and weeks and weeks to get more germinations out of these Persica hybrid seeds I got from overseas.
In total there were likely less than 100 seeds, I never actually counted them.
To cut a long story short, I had dried these up in winter and popped them in zip lock bags in the fridge, without water or damp paper. After well over 8 weeks in that environment, I removed them from the fridge, (dry as dry can be), and immediately sowed them in a media consisting of perlite : seedling mix (50:50).
Good news: After several weeks of waiting, I got one vigorous seedling which had fused cotyledons. I spliced these fused cotyledons into two and this seedling has since continued to be vigorous and has put on multiple leaves. It appears that Jadae /Michael was correct about leaving this seedling to its own devices!!
Bad news: I got no more germinations after many weeks of waiting, and it is now getting far too hot here to expect any further germinations (the southern hemisphere summer is literally here already as far as temps go!!!).
So I emptied the seedling pots and resorted to embryo extraction.
It was interesting to note that nearly 100% of the achenes which I was able to retrieve had rotted seed inside.
Good news: I managed to extract 8 embryos which looked viable, and planted them immediately in seed raising mix. Four of these 8 embryos are from PEJAMbigeye X OP. I am excited about that!
If I get any germinations from these embryos, they will no doubt happen in the next week or so!
After watering them this morning I also noticed one of the four PEJAMbigeye XOP floating on the surface after the watering. It was green with a small rootlet and cotyledons developing but still closed. I repotted that one in a quickly concocted mix of soil/seedling mix/perlite, and threw a thin layer of perlite on top of it, hoping it will spring up in a day or so.
I will try to post pix soon, but webcam is broken and have no other camera available atm.
Thanks for the inspiration you provide us through your own great work on hulthemia. It has inspired me and I am sure other members into persevering with this hobby.
Yes, Jim, and thank you for bringing Hulthemia’s beauty into GARDEN roses! Now, many of us can enjoy them in garden beds, instead of along the “fringes”. Great job! Thank you. Kim
I searched for the rest of them, time was slipping by… It turns out there was one more PEJAMbigeyeXOP showing signs of germination, so I potted it on in a similar way to its other sibling. There was no trace of the remaining 5 I had sown which does not surprise me.
Whilst we can never know why these others did not make it to germination, I firmly believe it is most likely they were just not biologically ready to germinate, as none appeared to be overtly damaged after their extraction.
I don’t have the set up / lab technology /expertise to truly “rescue” any of these more “recalcitrant/dormant” embryos for extended periods in an appropriately formulated culture media. All I use is simple seedling germination media, which cannot be the best environment to sustain life for many weeks for those more “dormant” embryos in the population which do not germinate anywhere near as fast as some of their siblings.
I just hope for the best…it is crude I know and there are many deaths, however soemtimes as in this case, I feel it is the best option to take. It is high risk to be sure!
Still, having 1 definite and 2 likely seedlings out of those eight embryos aint bad in my books.
I don’t have any answers but I do have a thought or two. Unless you can insure sterility, adding sucrose or other energy source usually leads to microbial overgrowth. So sticking with a simple medium is your best bet. But maybe adding nutrients would be beneficial, if not too high levels.
As for losing the other 5 embryos, perhaps you could consider a solid medium, rather than a potting mix type of thing. How about a block of oasis foam, wetted with a dilute soluble fertilizer solution. If enclosed there would not be evaporation and salt build-up. Roots can grow through it I’m pretty sure. Some hydroponic systems use something of the sort, such as for starting cuttings of poinsettias in the U.S. for winter solstice (and Christmas). If you place the embryos in known positions in tiny holes in the oasis, you could watch their progress or lack of it. Maybe you can even buy starter plugs of the stuff at a nursery supply outlet.
If the seeds were harvested 75 days or more after pollination then there is a good chance the embryos will germinate if given steady fluorescent illumination (24 hr/day) provided that they are kept clean (no soil); better still if they are incubated on a paper towel bed wetted with 500 ppm hydrogen peroxide contained in a Ziplock baggie.
Younger embryos may still germinate but with diminishing success down to about 45 days post-pollination. With the younger embryos use weaker peroxide solution, 200 ppm being the lower limit.
The keys to survival are light and cleanliness. Temperatures of 65F-75F are optimal though the lower end is better.
Hi Don, I am sure you are correct there about the hygiene factor and the light levels. I am lazy when it comes to those things, it is true!!
Hi Larry, what a great idea about that oasis foam stuff!!!
I am not being rude here, however for a while now I have been endeavouring to do away with embryo work altogether…I am nearly 100% converted over to stratification and germination by conventional sowing. This is the first embryo work I have done in well over 6 months. It might even be the last I ever do…only because I just don’t have the time for it any more and I find natural germination to be sooooooo much easier and time efficient to do.
Moving on a step from the embryo work in this case…ummmmm ALSO…I think I had not thought in advance about the optimal timing of sowing this seed…the thing is…I received it from overseas in our winter. It was immediately placed into refrigeration for many many weeks, and I am pretty sure it was sown in spring at a time when temperatures were already doing some pretty scary high spikes…ummmm is it possible I might have got significantly higher germination rates if I had sown this seed immediately when I received it in winter, so it could germinate when ambient temps were cooler??? … does that make any sense??
In the back of my mind I also wonder whether the fact I stored this seed in very dry conditions, deliberately omitting dampened paper towelling (or damp peat or whatever else damp) for many many weeks, explains the huge number of rotted seeds I found…just a thought/concern of mine based on nothing more than conjecture and fear!!
I forgot to add that is is also possible that this seed comes from hybrid persica parents which produce poorly germinating seeds. As I have no previous knowledge of these seed parents, it is all a guessing game at the moment. Best I don’t speculate too much.
Both those PEJAMbigeye embryos have increased in size very noticeably since 24 hour ago. It looks like the dirty conditions do not bother these ones, for whatever reason. The more advanced one of the two has popped its cotyledons above the media level, I guess it has germinated technically speaking, only its cotyledons are still closed and not fully greened up yet.
BTW… in reply to Don’s temp advice, the max ambient temps have been swinging madly here from 65F-95F for the last month or so, I guess. I heard tomorrow might be another 95F type day. This is normal weather for this time in the year in Sydney (late spring). This is why I guessed there were likely going to be very few (if any more) germinations in these sown seeds until at least cooler autumn temps arrive (which could take up to 5 months from now).
Anyways, now I can’t wait to see these seedlings flower!!!
Today is approaching 95F, it is very abrupt temperature escalation, and the two Pejambigeye now have that “I wanna die” look about them.
I have now taken some of your advice on board, hoping it may help them at this stage in the game.
I removed both embryo/seedlings from their pots, and I washed off the dirt covering their lower parts with gentle drops of tap water, and placed them on the surface of a pre-wetted paper envelope (wetted with tap water, I don’t have H2O2 immediately at my disposal). I then placed this envelope with them on top in a zip-lock plastic baggy. I do not have fluro lights, so I taped the baggie close to the computer monitor light hoping this might add some useful light for them.
I am now going to the shops to search for H2O2 and see what concentration it is, so I can get it to 500ppm and impregnate the envelope with that solution.
The other 2 hulthemia seedlings I have are in no danger and are thriving. They are:
Harkness(unknown hybrid persica) XOP. This one has been growing for many weeks and is taking this heat without any trouble, it remains vigorous++
and,
Peter James(unknown hybrid persica)XOP which is starting to develop its first true leaf after a few days germination. It is very green and growing fast. It was moved indoors today with a gentle fan going in the same room to keep it cooler than outside. Once the sudden heat goes away I’ll put it outside again.
So I added 1.67ML of this 3% stock H2O2 into 98.33ML tap water to make up a 100ML solution of H202 which I calculate to be close to 500ppm H2O2 solution. I hope the math is correct enough!
I soaked a fresh paper envelope into this 500ppm H2O2 till it was thoroughly soaked then wrun it out a bit, then placed it into a new zip lock baggie with some of this same solution sprinkled inside as well, and sealed the baggie and put it in the fridge.
Now I am soaking the two embryos in this 500ppm H2O2 for half an hour at room temperature, before they then go into the baggie with the impregnated H2O2 envelope. I’ll hang this baggie against the computer screen and kill the screensaver for a day or two hoping the extra light will benefit them.
Don, should I add a fresh batch of this H2O2 (500ppm) to the paper in the baggie over time?
Wow, George, you’ve got quite a process stream there.
If you look in the manual you’ll find the formula for the peroxide but you’re within three significant figures of 500 ppm.
I’d guess that what you have done is enough although maybe too late to have an effect. It’s a case of an ounce of prevention, once the bugs get to their food source the game is over. Once exposed your other options might be fungicides. I have treated diseased embryos with tebuconazole with mixed results. Light is the most important thing now, though.
That said, you had nothing to lose and you can try it again with more hulthemia seeds, can you not?
I forgot to consult your manual the time I posted the message above… dughhhh!!!
I’ll keep these 2 embryos in the baggie set up and keep the light going 24/7.
The next time I’ll have hybrid persica seed will very likely be when these babies flower and I get crosses. My source for this seed was a one-off very generous gift from a very busy man. Not the sort of thing I dare ask for again.
Still, I am real happy. I already have 2 seedlings which is good odds for a blotch. Any more seedlings (ie. either of these 2 Pejambigeye in baggies) will of course be cream.
Crossing fingers
Thanks again for the advice. At least now I have tried your method, and to be honest I really like it, it makes a lot of sense.
BTW, your embryo manual which I had read quite a while back, is fantastic. Congratulations to you again for creating it!!!