Germination research (Rosa canina) Seeds

That last one worked, I can see it! Looks like your problem is solved with the update.
Very interesting to see your pond and get an idea of what your method looks like!

As Cassius said “I beat the big ugly bear” … sort of, … first real rose germination of proto leaves March 15.

First seedling to germinate is a cross of a gallica x explorer, specifically a Nordic hybrid gallica seed parent, and a Canadian Explorer series pollen parent that is documented to be a cross of R. kordessi, with a Simonet effort (modern x R. laxa).

The stratification regime below and as per on-going quest to improve (get) germination from hardy to bone hardy crossings.

e.g. Gallica x Explorer

There was in total ~128 days of cold stratification at marginally +/- 0C for 4 months. Steps as below:

  • cross harvested September 16 2022 cleaned and open bagged
  • 1st stratification period at marginally minus 0C from October 5 - Jan 30 2023 - duration ~110 days
  • 1st warming period at 15C from Jan 30 - Feb 26 for ~ 28 days .
    Zero germination.
  • 2nd chill period at marginally plus 0C from Feb 16 - Mar 6 for ~ 18 days
  • 2nd warming period at ~ 18C started Mar 7
  • 1st germination occurred Mar 16, or 9 days after raised to 18C

Data from from my 2022 season hybridization log.

Post script 1 March 20:

Nordic gallica hybrid seed parent crosses germinated in second warm period vs none in first 28 day warm period. They were three 3 different cold zone pollen parents varying from semi-hardy (explorer), to bone hardy (Suzanne and R. fedtschenkoana). The Explorer cross germination ended at 7.

#1 Nordic gallica hybrid x Explorer (7)
#2 Nordic gallica hybrid x Suzanne (2)
#3 Nordic gallica hybrid x R. fedtschenkoana (2)

If these are true crosses then seed parent is a true star mystery singer whose identity will be unmasked if they fail to qualify beyond the preliminaries. And holding my breathe to see if following germinates, the Nordic gallica hybrid x (Red Dawn x Suzanne)

Ploidy (public domain) information on the 3 pollen parents classified them as tetraploid. The Nordic gallica hybrid singer seed parent ploidy has not been published.

A University of Guelph ploidy historical survey of species ploidy (by McPhail and Kevan 2009) from various qualities of work lists R. gallica “Officinalis” and R. gallica L. as being tetraploid. Therefore an odds on favourite guess is tetraploid for the gallica seed parent.

So the three crosses that germinated are likely true crosses if they are the same ploidy. They were stratified +/- 0C to germinate vs stratifying at a temperature range of 35Fto 45F that failed continuously for me (World go metric and right hand drive - please).

Above are self-taught learnings by 2ndary goal seeking to breed a bone hardy gallica hybrid cross for northern Canada (good to -35C). Might supplement Percy Wright’s “Ruth” hybrid 1947, Agatha (I call it a gallica), Alika and Splendens … and might be 3 new types in total.

Remaining gallica crosses not germinated as to date are triploid and diploid that learnings suggest lower odds of germination.

Nordic gallica hybrid x (Red Dawn x Suzanne)
" " x Bill Reid
" " x Polstjarnan
" " x Porsliini Kaunota
" " x R. blanda “Herttoniemi”
" " x RR#1

Post Script 2March 22:

  1. “0” germination from first long deep chill and 28 days warm period

  2. 12 germination’s from 2nd chill and warming period, consisting of 4 varieties.

  3. Third 3rd chill period started March 21. Using +/- 0C temperature range, with a target duration of 14 days.

  4. 58% of plant count after 2nd chill from the Nordic gallica - explorer cross for 2nd warm period.

  5. Germination % vs total seed count for crosses was 6.6%, and 12% for Nordic gallica x explorer.

  6. Error, qualitatively assigned to seed count as +5% / -20%.

  7. First long duration stratifying at -0C in the method will likely be cut in half next year. Change will be due to no germination during first warming period after long stratification - test temperature cycling - maybe more important.