Nice seedling

This is a nice open-pollinated Bonica seedling, nothing special, but the colour is nicer than Bonica and it is quite floriferous. It gave me two blooms before it produced this cluster of flowers. There is another cluster on the young seedling. I have about 50 seedlings and not one flowers as heavily as this one (yet). As expected the fragrance is only very light. I wonder what happens if I plant it outside, in wind and rain…


It looks very nice Rob. Does the plant seem to be smaller than ‘Bonica’ with more petite plant parts in general? With root tip squashes I learned ‘Bonica’ is triploid. Who knows what ploidy this seedling may be. It would be neat if it was diploid. It doesn’t look like it produces normal pollen or pistils, at least here in this photo. Does it produce some normal reproductive organs sometimes so you can use it further in breeding? I look forward to your updates on it. Sincerely, David

Is it possible that Bonica has different ploidy levels?

In my own breeding experience Bonica was looking to be tetraploid.

Also in the thesis by Leen Leus (Table 5.1 Ploidy levels in the DVP-rose collection) is Bonica analysed as being tetraploid.

As Henry Kuska mentioned before, the thesis of Leus can be downloaded from:


Good question Martin. Leen told me she confirmed it was 4x in last Sept. It could be that there are 3x and 4x lines out there. ‘Royal Bonica’ is 3x, a sport of it. The version I confirmed of ‘Bonica’ is what Bailey Nurseries is selling. ‘Bonica’ does have good fertility for a 3x plant. Perhaps it is a chimera? 3x in layer 3 of the meristem where root tips originate on cuttings and 4x for layers 2 and 1 to give it good fertility? I think Leen used flow cytometry. Flow can be used to help understand if a plant is a “mixoploid”- different ploidy in different layers. I have to look at her thesis again. Flow is an indirect assessment tool and errors can occur as described in another paper with roses. Maybe in Europe they have a 4x version?



Hi David,

My Bonica is very fertile and self-seeds readily. The OP seeds also germinate very well. If it truly is triploid there is no reduction in fertility at all. My seedling has about the same leaves and flower size as Bonica, so I don’t think it is diploid. Either triploid or tetraploid. Before the five flowers in the picture, this seedling had only two flowers. All had a vegetative center. However, the flower on the left (the youngest) also had some pistils. I often read that vegetative centers disappear when the seedling matures. Maybe the other younger cluster on the seedling shows more pistils. I’ll have to wait a bit longer before the flowers open.


In my experience vegetative centers often persist and may come and go dependent on the vigor of the plant. It seems vegetative centers are most common when the plant is growing vigorously.

I have read in W. Kordes II book, DAS ROSENBUCH in German, (where I learned “ALL” my hybridizing from 35 years ago) that once a vegetative centre, you will most likely always have vegetative centres.

It would be interesting to learn how your seedling does in it’s second year.

Unless, like many of us with seedlings we particularly like, you have been fertilizing it excessively… Robert R. is right…

Concerning the ploidy level of ‘Bonica’. As mentioned by David, I checked the leaves with flow cytometry, they were tetraploid. But as David tells, it is possible that other cell layers have other ploidy levels. We noticed before in other plant species roots can have different ploidy levels compared to leaves, but this is very rare.

I also checked the size of the pollen as you can see in fig. 5.2 of my PhD. I must say I checked more cultivars than mentioned and the pollen of ‘Bonica’ was the bigest of all. So a second reason to think it is a tetraploid cultivar. What is the fertility of ‘Bonica’ in the US?

Bonica is a trade mark, not a cultivar name as such, so in theory it is possible that there exist different genotypes with the same commercial name. But I don’t think that will be the case.

The variety Bonica is quite fertile here. The majority are supplied by Star Rose (like many Meililand roses) but a few other companies like the own-root vendors offer it as well. Except now (within the past 2 years or so)it is also quite available from a lot of cheapie bareroot bags companies.