I thought I’d throw this out for discussion. I’ve noticed that some roses basically put out a hip for every bloom (in my case the two roses that do this for me are the Austin roses “Graham Thomas” and “Sharifa Asma”). Since these roses are quite double and I don’t know that I’ve ever seen a bee pollinating them (although I don’t get a lot of mid-day viewing of my roses). I suspect in the case of a rose like this that most of the seeds in those hips are selfs. I believe that roses generally have self-incompatibilities built in, but also that the doubling of the chromosomes may have ‘broken’ this mechanism.
I would think the consequences of this might be two-fold. There would be less variation the seeding population from such a cross and the seedlings might be weaker from inbreeding depression.
Any thoughts?
Chris
Hi Chris,
Great points brought up. A few years ago I wrote a couple articles for RHA regarding inbreeding. In one of the articles I described the characteristics of ~28 selfed seedlings of ‘Carefree BeautyTM’. From it I learned that CB has some “recessive” alleles for dark filaments (like in ‘Dainty Bess’ and others) as well as only having one copy of the dominant allele for the major gene governing double flowers. This information helps me choose pollen parents that would have a better chance at drawing out traits of interest.
I raise op seeds from new rose seedlings or cultivars I am considering using as parents to see the diversity of progeny even though the seedlings may be from self or cross pollination. Seldom have I obtained a superior seedling worthy of cultivar consideration from op seed. However, raising especially selfed seed I believe has great value. Not only does it reveal some of the potential traits we can draw out from the original parent, but we can use the most vigorous selfed plants possessing valuable traits as parents and can make greater progress in the end at times. Investing in parent building for traits of interest can definately pay off. Using inbreeding to “sieve” out some of the “deleterious recessive alleles” or unwanted dominant traits can in the end produce better progeny as we outcross such inbreds. This is a common technique used in polyploid agronomic crops that suffer from inbreeding depression such as alfalfa as well as the ornamental chrysanthemums. In alfalfa, if one got progeny after a couple generations of selfing the general average quality of further selfing generations began to increase as the deleterious recessives were sieved out. In mums sometimes selfing is too extreme of inbreeding and with sporophytic self incompatibility it may be hard to continue, so other forms of inbreeding which are less intense are used like sibling mating.
When I try to use ‘Baby Love’ or ‘William Baffin’ as female parents they don’t take the pollen I apply on them usually, but set a lot of op hips. I wonder if they are primarily from selfing. As I raise op ‘Baby Love’ seedlings they are all single and yellow suggesting that may be the case.
There’s a recent paper Henry highlighted in the newsletter about using diploid roses with strong self incompatibility to study gene flow since seedlings are primarily crosses with other roses. I take advantage of this with my diploid polyanthas and rugosas trusting that progeny are primarily crosses.
Are you going to raise your Graham Thomas and SA seeds to see what you get?
Take Care,
David
There was a thread on the forum last year that had some discussion related to this topic:
Link: www.rosehybridizers.org/forum/message.php?topid=913
Are you going to raise your Graham Thomas and SA seeds to see what you get?
At least some. I also have some crosses with each of these, so it will be interesting to compare. I have more
crosses with GT for though I prefer SA, I’ve been told through this forum it’s progency tends to be poor.
Another thought about these “selfs”. As hybridizers we would probably need to be extra careful with these as it may be hard to know (except, possibly, from the results) whether our cross is from our cross pollination, or unintended selfing
Chris Mauchline
David, I noticed exactly the same thing this year when I tried to use William Baffin as a pistillate parent; everything I’d pollinated simply aborted some time later, while the flowers that were left to their own devices easily set OP hips.
Chris, careful emasculation of a bloom at the right stage can eliminate much of the worry over unintentional selfing. Even though there is always a small chance of it still happening, the majority of seeds produced will still probably be from the planned pollination. This brings up something else I’ve been curious about: is it possible that fertilization from several sources could be an advantage in attempting crosses where the pistillate parent tends to refuse pollen from some certain other rose when it’s used alone? In other words, if you mixed a minute quantity of pollen from one “palatable” variety with a larger amount of pollen from another that is generally refused, might a seed or two resulting from the former act as a sort of crutch that allows the plant to tolerate pregnancies in the same hip by the latter pollen? Maybe it depends on the cause of the initial refusal, but it might be worth trying before abandoning a cross - especially if it’s potentially very valuable. Or is the answer to this all old news?
Since you brought up pollinators, I thought it might be interesting to add what I’ve witnessed. There are virtually no honey bees in my garden, and bumblebees tend to do a lot of the work of pollination here. But they seem to rarely, if ever, bother about roses. The only bees that tend to visit roses are small ones, maybe carpenter types, and I’ve always observed them engage in a collection dance around the anthers while very carefully avoiding the female parts in the center. Whatever pollinator (if any) is causing OP hips to form here is actually a mystery to me, and I’ve never seen it happen in the cases of very double flowers with anthers buried amid the petals. If such a thing ever did happen here, I’d probably wonder if it wasn’t because of rose chafer beetles or earwigs, or some other such creatures : )
Stefan
Stefan,
I agree that emasculation should eliminate most of the concern, but in one case I did a cross of Sharifa Asma X
Reine des Violettes. RdV has very paltry and poor stamens (requires multiple flowers to get enough to do a pollination), and I’m not convinced of the pollen viability. So when I opened the hip and got 3 seeds (only one of which sank [though I’m stratifying all 3], I’m not sure whether the seeds are from selfing or from my deliberate cross. I guess I’ll have to see what I get.
I do know that on Graham Thomas (and perhaps Sharifa Asma) that of the most successful pollinations I deliberately did the hips are larger than the most of the OPs.
I also noticed from some crosses, that even with significant seed set, on some crosses, none (or almost none) of the seeds sank, but on other crosses w/ same seed parent that most of the seeds sank. This raises two possibilities with me 1) the crosses where the seeds did not sink are non-viable (at least in this attempt) or 2) [and IMHO less likely] the seeds may be still viable but that the pollen parent can affect seed “weight”. Example: Graham Thomas X Scentimental - all floated/ Graham Thomas X Gina Lollibrigida - most sank.
By your message, are you saying you’re not seeing hips form on very double flowers? I’m not sure where SA and GT fall in the double/very double scale, but they are agressive hip formers. (Maybe Japanese Beetles are doing the pollination? 
Chris Mauchline
Of course, I realized today that the agent responsible for the selfings is probably the rose itself - as the anthers so often curl towards the center to finish any job previously left undone or incomplete. That’s probably why very double flowers never set hips for me, because there are too many petals in the way even if the meager few anthers did want to move about. I’m also not sure just how double Sharifa Asma and Graham Thomas are, but if there are anthers in the center close to the stigmas, they can probably behave just like any other functionally self-fertile rose.
I think it was Enrique who mentioned before that Reine des Violettes has good pollen, just not a lot of it. I’d say chances are reasonably good that your three seeds are the products of artificial fertilization if your emasculation didn’t go horribly awry and/or bees didn’t find your newly pollinated GT blooms strangely intoxicating for some reason ; )
If you had a lot of floaters available, you could cut some of the seed open to see if a healthy embryo is present or missing - but germination rates will prove just as telling so I’d wait.
We’re not supposed to have very much Japanese beetle activity here yet (though they are known to be in the area and increasing). I’ve always thought that they are the beetles I find in the petals of Iceberg towards the end of the first flush and beginning of the second, but even if they are, they disappear for the year after I’ve killed that batch. They seemingly never bother any of the other roses, but I did find one hiding in a White Dawn blossom last year. White Dawn did set a number of OP hips but as it doesn’t have terribly many petals, I (hopefully) doubt I should have any JBs to thank just yet : )
Stefan
I should have said that it is the stamens that curl toward the center… and more correctly the filament… not really the anthers. Not that anyone here would be confused, but innocent visitors could accidentally be led astray and I’d hate to see that happen : )
Stefan
Bee and Bumblebee and generaly insect efficiency should not be underesteemed. Everywhere many/most flowering plants rely entirely on insect pollination. Species roses particularly.
Honey bee activity is maximum when dew stops building up and begins drying if temps are above 12
Pierre, what you said is very true - and as I do have such an abnormal garden, my experiences probably don’t apply that well to other areas! If I didn’t have the conditions I have to deal with, I’d probably learn to expect a great deal more insect pollination - and open-pollinated hips - than I do now. But I must say that it probably often works to my advantage to have such a picky set of natural pollinators : )
Stefan
Stefan, you’re garden may not be all that abnormal. It sound similar to mine (NH. I have very little open pollination despite the fact I grow about 500 roses in my garden. I have very few honeybees if any, quite a few bumble bees that just as soon pollinate the rhododendrons. I also have many small native bees similar to what you described that tend to hop around the anthers without touching the stigmas. The first flush of roses during late June and early July end up with very few OPs. The later blooms have more OP’s but don’t ripen before the cold weather sets in. The only time I have seen the small bees on the stigmas is after I have emasulated the rose and applied a good amount of pollen onto the stigmas. I have also seen these small bees go between each of the different cups in which have the pollen I’m using. (So much for pollen integrity).
You also referenced that Reine des Violettes has good pollen. This may be the case but I have had little success with it. I’ve used it on at least a dozen different varieties in the past couple of years and have only one seedling from it(Heritage x RdV)that has yet to bloom. I have never got a hip to set on Reine des Violettes that resulted in viable seeds despite pollinating it with everything I had available.
Chris metioned using Sharifa Asma which I find is very fertile as either a pollen or seed parent. I have had success with it both ways but it does produce a lot of dogs in the process.
John
Sharifa Asma has produced nothing but garbage for me, and so I abandoned it. Try St. Swithun instead. (see URL below)
Regards,
Paul
Link: rdrop.com/~paul/gallicas/allegra.html
Hi Chris:
I think of roses as being a very mixed bunch of individuals. Some may have built-in incompatibility that helps put pressure on the production of true crosses. In other cases, it seems that some roses prefer to self pollinate. I don’t know why, but it seems to be the case. In those situations, I believe that avoiding emasculation and just applying your selected pollen early would be a good strategy.
The vast majority of my seed fertile seedlings that are grown in the greenhouse will very readily self pollinate. I have grown thousands of self (open) pollinated seedlings. There are very few that are exciting and the color range is always less than when selected pollens are applied. I agree with David though that planting ‘OP’ seeds is a very important step in rose breeding for the reasons he has given. Also, it gives me a chance to assess germination rate. Efficiency in rose breeding has been very important to me. I have been fortunate to discover very fertile (seed fertile) roses among my seedlings which I use extensively.
Jim Sproul