Regarding your intended use of Spinosissima roses as seed parents (Rosa altaica is closely related), keep in mind it generally takes two years to germinate the seed.
Also keep in mind that with species roses crossed with modern shrub rose cultivars, it seems to work best if the former is used as the staminate parent. Even with Rosa rugosa cultivars crossed with species roses, I think most of the time the former has been used as the pistillate parent. It certainly is my approach in this type of breeding program, but perhaps more work needs to be done doing the reverse cross and then comparing results.
‘Metis’, of course, is a successful example of using a species (Rosa nitida) as the pistillate parent with a complex hybrid (‘Therese Bugnet’).
By the way, ‘Winnipeg Parks’ may not have a great reputation producing disease resistant seedlings, but I have one with Rosa acicularis as the staminate parent and the shrub is clean after two years. It should flower for the first time next year.
Thank you Paul, I am glad your cross of Winnipeg Parks & R. acicularis worked, it gives me great hope! And thank you for the tip on the two year time required to germinate Spinosissima seeds. Have you had any success with embryo extraction?
Larry, my goodness, how could I have forgotten about Therese?!!! She is also a favourite in my yard. It is great to know you got hips from Therese in 8 weeks, that is fantastic. I find Therese is a refined monster - I appreciate her smooth new red canes, unique matte pointed narrow leaves, elegant buds, early fragrant blousy blooms, tall height, vigorous growth and extreme hardiness. It’s funny, one of my Therese Bugnet plants was a bagged bare root rose from a big box store, and the bag said it was from the Texas (http://forums.gardenweb.com/discussions/3036707/bodybag-roses-in-the-north?n=9). Amazing to have a rose bred in this province make it’s way all over the world! Now I am imagining if a white or apricot flowered Therese Bugnet was developed one day, or one with a darker pink center and lighter outer petals.
I noticed only a couple roses on HMF which used Therese as the seed parent in 1st generation and which had photos, ‘Thérèse Bugnet × Topaz Jewel’ and ‘Helvi.’ Again this gives me hope. I do like how these roses with Therese as seed parent seem to have retained more characteristics of Therese’s foliage, unlike the other crosses where Therese is listed as the pollen parent. Is it more common for a rose to resemble the seed parent?
Another rose I may re-add to my collection for breeding purposes is Prairie Princess. I killed her when I tried to overwinter her in a pot, at the time I thought she was just another pink rose but I’m learning: it looks like she has many, many descendants and might be a good one to practice breeding with. Although I wonder if Prairie Princess would work better if the breeding plan gears towards the modern roses…
It appears my first step in choosing the right plan is to determine who my main seed parents will be. Thank you again to everyone for all the helpful input! I also welcome any ideas in other good seed parents for my area.
I’ve used Prairie Princess for the first time this year, and it is setting some huge hips. I remember an offhand statement that Julie Overom, a very experienced breeder, made about Prairie Princess that she produced some of the more cercospora-resistant seedlings she has had. (I don’t know if you have cercospora leafspot in your area yet; the best indicator is William Baffin, which is healthy otherwise but defoliates from cercospora.)
It seems like it would be wise to cross Prairie Princess with some of the more disease resistant-moderns such as Will Radler’s roses to try for a rose that is as stunning and hardy as Morden Centennial but healthier. Or is as lovely, hardy, charming, and disease resistant as Prairie Joy but with heavier rebloom. This morning I pollinated her with Peppermint Pop and Darlow’s Enigma.
If you have room for a huge species rose in your yard, I’d recommend getting a R. carolina or R. virginiana. I think they do great things when crossed with moderns in terms of vigor and disease resistance. Because they are tetraploid, they are fairly easy to cross with moderns (when using the species as pollen parent) but it is a somewhat long road to recover rebloom. I would love to see Therese Bugnet x R. carolina, for instance. I am in zone 3b and they have been quite hardy here. About eight feet tall this year.
Going back to Prairie Princess, I wonder if that would be one to try with rugosa pollen. First generation modern polyploid x rugosa or vice versa can give interesting results, and with the hardiness, doubleness and potential to pass on rebloom of Prairie Princess you could end up with a winner.
‘Prairie Princess’, of course, is one of the parents of ‘Morden Centennial’, so I don’t know if there is much advantage to use it compared to the latter, except its characteristic of producing tall seedlings if one is pursuing a Climber or Pillar rose breeding program. For example, in a cold climate combining it with some of the Explorer Rosa kordesii tall cultivars, and Rosa laxa hybrids (still mainly to be developed). But it’s hard to ignore this cultivar as a staple pistillate parent in a cold climate (Zone 2 and 3), because of its very good fertility and large hips that produce seeds that germinate easily. I always like to have it.
I can’t adequately judge. The seeds did germinate. Nothing spectacular in their first year. I think I had several PP x Lemon Fizz…fairly bland colors there. Probably a tendency towards lankiness.