RESUTLS RE: A STUDY USING WATER AS A MEDIUM TO COLD STRATIFY ROSE ACHENE (SEED): 8 WEEKS OF COLD STRATIFICATION IN A GLASS OF WATER OF 73 OP ICEBERG ACHENES.

RESUTLS RE: A STUDY USING WATER AS A MEDIUM TO COLD STRATIFY ROSE ACHENE (SEED): 8 WEEKS OF COLD STRATIFICATION IN A GLASS OF WATER OF 73 OP ICEBERG ACHENES.

Nine seedlings germinated out of 69 sowed (ie ~13% germination). The fist germination happened just past the three week mark from sowing, then there was a peak and then a drop off to the germination rate.

To summarise, these achenes were cold stratified in tap water in a sealed glass jar in the fridge continuously for 8 weeks, then 69 of these were sown in soil in a pot, outdoors in our spring. This spring turned out to be wetter than normal, but there have not been any unusual heat waves, which sometimes occur here this time of the year. The weather has fast approached summery conditions now, which is why I am calling it an end to the study now, in the belief that it is highly unlikely there will be more germinations as it is very warm now, some days are getting very hot.

I watered these achenes and the newly sprouted seedlings with a 10% NPK soluble fertilizer solution once every single day, from day 1 of sowing.

These 9 seedlings are doing ok, one has a partial photosynthesis defect, but seems to be “growing out of that”, (could it be virused, who knows??).

The weather this spring has been a rose hybridizer’s nightmare, totally unpredictable rainfall, dumping rain for some days in a row here and there, and overall very damp and humid. There has been a great deal of powdery mildew and blackspot everywhere.

I am happy enough to continue soaking rose achenes in refrigerated tap water in a jar, as my cold stratification system, I just can’t be bothered messing with baggies, moldy paper towling, peat etc etc.

I have no idea whether this method compares favorably or not to other more conventional methods of rose achene cold stratification, as I have never used any other cold stratification method to compare it with.

George,

dunno the germination rate of ‘iceberg’ if conventionell stratified, but 13% seems a bit low.

Mine are in zip lock baggies, together with alittle wet perlit. The baggies I put together in a tupper box. I find this very clean and convinient, it does not need much space.

but everybody has to find the best way byself…

anyhow…thank you for your detailed report.

cheers

Bernhard

Hi Bernhard.

Thanks for the post mortem /debrief, LOL.

Yes, your comments make me think of the saying, “if it aint broke don’t fix it!”.

Actually, I really can’t comment further on the germination % of this study, I feel it would not be very meaningful as there was no control group for comparison here.

When I thought to do this study, my main AIM was to find out if it was actually possible to get any germinations in such a wet & cold environment, or would the achenes have all rotted. I really was surprised that the achenes seemed to me to be just as hard after 8 weeks in chilled water, when I cut a few open to check what was going on inside.

Also, I would like to mention, there are a few variables to consider here, as well as the actual stratification method:

*The local OP ‘Iceberg’ achenes seem to have lots of dead/empty seed inside the achenes. I have used such achenes in my random embryo work (see above 12+ months of entries/photos as examples). I am predicting from this occasional embryo work I have done on OP Iceberg, that Iceberg is not the greatest of seed parents, but this is conjecture based on some of these indirect observations.

*Climate/temperature…the sowing was done very late already into warm cycling of weather.

*The harvested hips were very deeply colored, some rotting, and so the achenes were likely at their hardest possible state.

*I am pretty confident the fertilizer solution was not a negative factor, as I have even sprouted naked embryos floating in such a solution for like 7 days or more, and ended up with some happy seedlings.

CORRECTION>>>>>BTW the fertilizer solution stated in the final summary above as 10% NPK was meant to have read as “10% X (full strength) NPK”.