Hello all,
Last season I pollinated Darlow’s Enigma with various parents and have experienced quite divergent germination rates. Does anyone have any thoughts as to what influence pollen parents have on germination might be? Here is a sampling of pollinations and corresponding results:
x Mutabilis - nearly 100%
x Abraham Darby - about 50%
x Carefree Copper (thanks for the pollen Larry) - 0%
x Baby Love - 0%
Interested to hear your thoughts.
Mike
How many seeds did you get per hip? That will tell you something of the compatibility of the two parents. More is better obviously but but the potential # is set by DE. A low # indicates a poor match which might yield a seed that is inviable after partial development. So the hips may contain only empties.
Also recall that it was shown many moons ago by Risley that for a single mother plant the pollen parent to some extent determines the time until germination. When did you plant or stratify your seeds. It is quite possible they entered in to a deep dormancy. Some CV take a great many months at 4 C to germinate. For instance R canina may be 6-9 mo. That depends greatly on date of harvest and the extent of after-ripening that happened before dealing with them.
Different selections of the same species may have a large variation in time and % germination. I found that with hips of R. palustris from several relatively nearby locations sent to me by jwindha.
Sometimes if you warm them to room temp for a month after 3 mo cold, then return to cold another 3 mo you can get a decent sized response if you take them out of cold again. That is what von Abrams and Hand (1950s) did with all their crosses trying to use species and moderns combined. I believe they used 4 cycles. I have done similar with canina, pomifera. Continuous cold is no substitute for cycling. Dr. van Fleet typically retained flats with planted seeds for 4 years using the natural weather cycles of summer and winter around Washington DC.
Mike,
First comment, Hooray for ‘Mutabilis’.
The ancestry of ‘Abraham Darby’ is somewhat complicated, so maybe 50% is pretty good.
Rosa foetida bicolor was the pollen parent of ‘Carefree Copper’, which does not bode well for pollen fertility, and compatibility is another complication.
As for ‘Baby Love’, which one? The single yellow is a triploid, another bad omen. I have no info on the pink Italian variety.
Have you tried pollen mixtures? There is evidence (including an item from Darwin) suggesting that a seed parent can be “tricked” into providing extra nourishment to seeds fathered by an unfavored pollen parent. Just add some pollen that is known to be compatible. With both pollen types growing down the same style, the seed parent provides about the same nourishment whichever pollen tube gets to the ovule first.
Karl
Larry & Karl - Thanks for your responses. Apparently Darlow’s Enigma is not a prodigious producer of seeds per hip, but does set very small hips easily. Generally I could depend on about ~4 seeds per hip and the general count was not different between Mutabilis, Abraham Darby or Carefree Copper. As father Baby Love (Scrivens) produced smaller hips, usually with only one seed in them, a circumstance that cropped up (excuse the pun) for this father with a few different mothers last season.
Seeds were stratified in my little wine fridge which has temps between 45-55 depending on position in the fridge, for about three months, then about three or so cycles of two-week periods of warm (countertop) then cold (wine fridge), then planted out.
I think Darlow’s Enigma has much to commend it, and would try using the pollen, but have read (maybe here) that it is much superior as mother than father.
I wonder if anyone here has obtained nice seedlings from it - I would be interested to see or read of results.
Best regards
Mike
I cannot speak as to why, but I had read that mutabilis pollen is frequently quite cooperative, and often can be used to pollinate some otherwise unwilling mothers. I have some setigera x mutabilis seedlings growing now, but R.setigera is usually selective of other synstyllae, reportedly. I was able, that same year, to get hips from some (I believe triploid) wichuriana derivatives, but none germinated.
I’m not sure of the ploidy of your roses in question, but I would imagine that is another potential issue.
The saga of Darlow’s Enigma continues. I don’t know if you’ve read the posts from earlier this winter in which I bemoaned my low germ percentages from DE. Jim was kind enough to send me some open pollinated hips from his plant, and I was hoping that I’d have better luck because maybe mine had been attacked by some sort of insect that burrowed into the hips (something Margit had mentioned here a year or so ago). Anyways, I tried some complicated stratification methods for half of the DE seeds from Jim, while keeping the other half moist at about 50 degrees F. I got two germinations out of 333 total seeds.
It’s really interesting that you got near 100% with mutabilis.
I admit jealousy of those that can work with Darlow’s Enigma, as I think it has a lot to offer. I’ve had about five OP seedlings of it in the field, and they showed good promise in terms of combining hardiness, bloom power, and blackspot resistance.
I’ve also used it a bit as a pollen parent. I don’t see anything inherently wrong with that. It’s just that if you’re putting its pollen onto a tetraploid the influence of DE will not be as strong as it would when paired with another diploid. Sometimes hard to know for sure if a seedling is the result of a successful cross. Using it as a pollen parent might be what I will have to be resigned to if I can’t figure out how to germinate the seeds.
Your results with different pollen parents make me want to try some controlled crosses. So far every time I’ve tried to pollinate DE I pollinate about two blossoms and get so frustrated with the tiny blossoms and flimsy pistils that I quit.
In regards to different pollen parents and germination, I want to note my experience with R. setigera var “Serena”. I did a few pollinations onto it and collected lots of OP hips. Hundreds and hundreds of OP seeds yielded zero germinations, but I got a handful of germs from the hips that had been hand-pollinated. Not sure if Serena can have “cryptic” seed set where it makes achenes without embryos? I didn’t cut any open at the time.
And one other note with regard to germination and pollen parents…I think I posted about this a few years ago. I remember having R. foliolosa seed in the same flat from different pollen parents. Sown on the same day, the seeds of one pollen parent germinated a few days earlier than those of another pollen parent.
Risley (1958) studied this matter. His mistake, I think, was overlooking the fact that embryos derived from different pollen parents may also differ in their preferred temperatures for growth. After dormancy is broken, but the seeds are still kept cold, some of those emerging sprouts will grow rapidly in the cold, while others slowly trudge along. The latter group are more likely succeed in the north, or any place where winter is often interrupted by warm spells.
Now I’ll state an obvious fact: pollen tubes are tiny plants with properties and traits that are based, in large part, on the genes they carry. Some plants are habitually pollinated at low temperatures, so we should expect that their pollen tubes will grow best at lower temperatures. Sometimes the pollen tubes grow well enough, fertilize the ovum and all seems well, but the seed fails to germinate. It is easy to dismiss this as “just the way things are”, but sometimes it is a matter of temperature, as Takatsu et al. (2001) reported for Gladiolus tristis.
http://bulbnrose.x10.mx/Heredity/PollenTemp2001.html
Egg sacs (female gametophytes) are also little plants with inherited properties of their own, but I don’t have any useful information on them.
A while back I was reading up on desert plant life and was a bit surprised to learn that many desert plants are pollinated primarily in the early morning or late evening. Insects, even in the desert, avoid very dry hot air. And I have observed here in the southern California desert that hummingbirds are active in the early morning and late evening, but are nowhere to be found during the heat of the day. So, when working with desert plants or presumed xerophytes, cooler temperatures might give some advantage to their pollen tubes. [Note: Rosa x hardii originated as a chance seedling, presumably from a cross of R. clinophylla and R. persica. Attempts to duplicate the cross reportedly failed. Did anyone try pollinating at low temperatures, rather than whenever it was convenient for the experimenter?
On a separate track, I recently learned that Rosa nitida is fragrant in the dark. This suggests that it might be bred more successfully at lower temperatures,
Karl
I want to mention another fact that seems to get overlooked. When it comes to pollen, quantity counts. So does quality (diversity).
Back in the 19th century, Naudin experimented with pollination of Mirabilis jalapa (four o’clock). Twelve flowers were given two grains of pollen. Only one seed formed from the group. Seventeen other flowers received one grain each. Again, only one seed from the group. And the two seeds grew into miniature plants.
Subsequent research has verified Naudin’s research, and expanded on his observations. For one thing, the one-grain plants were short-lived as well as dwarfed. After 90 days, none survived. But a more telling observation (I think) is that diversity of pollen was about as important as quantity.
Mirabilis has a single style leading to a single ovum. Only one seed can form, so what do the other pollen tubes contribute? I doubt that they contribute anything. Rather, they stimulate the seed parent to invest more heavily in the seed.
Roses have multiple styles. Quantity and diversity of pollen would have to be figured for each pistil, rather than for the whole flower. John Cook, who gave us ‘Radiance’, acted on this principle. In 1905 he wrote, “As the pollen sometimes is very scarce, it is better to put it only on two, or three pistils, repeating the operation the following day.” And in 1906 commented, “It took twenty flowers of the Marechal Niel to produce enough pollen to fertilize one flower.”
Karl
Philip - the ploidies are as follows (as far as I have been able to determine):
Mutabilis - 2x
Abraham Darby - 4x
Carefree Copper - 4x
Baby Love - 3x (but has proven itself as both mother and father judging by the HMF 1st-gen descendants).
If you’re looking to “spread any pollen around” (or vegetative material) on your setigera serena x Mutabilis, you’ve found a very willing and highly interested recipient 
Joe,
I read on this forum, maybe in relation to your post from earlier this winter, which I cannot recall having read or not, that A) Darlow’s Enigma was thought to be very similar to multiflora (I can’t vouch for that one way or another) and B) that it germinated better with constant temps around 50F (or was that for multiflora?). Not sure, but reading that gave me the idea to use the wine fridge, with temps around 50 vs the regular fridge with temps just slightly north of freezing - I believe it’s usually set around 37F or so for most residential fridges.
The number of hips for each cross was low…only five or less for each pollen parent. I can’t imagine 333 seeds of anything at this point!
The flowers ARE very small and the hips ARE very small, so the pollination does take some patience. Not to mention that the flowers sometimes snap off easily while you are pollinating if you grasp them too tightly. So not an easy parent to work with from that perspective. But sometimes bigger doesn’t necessarily mean better.
I had read somewhere that Darlow’s Engima as pollen parent tended not to confer the disease resistance it is renowned for, with many seedlings prone to mildew especially if I recall what I read correctly. Perhaps that resulted more from the choice of mate, however. I did not use Darlow’s Enigma pollen in any crosses last year.
Coincidentally, I have a plant of R. setigera serena and hope to work with it perhaps this year, if it blooms. I am discouraged to read of the “hundreds and hundreds” of non-germinations, though I’m not really planning on OP seeds. Fingers crossed that controlled pollinations will result in germination as they have in some cases for you. I would be interested to know what crosses you did with serena that resulted in successful germination and what the resulting offspring were like.
Regards,
Mike
Karl, how do we characterize what is “enough pollen to fertilize one flower” if a single pollen grain will do the trick? Or do we assume from this comment that most of the pollen collected was not viable? Something about this quotation doesn’t smell right.
Thanks
Mike
Mike,
I used Cherry Frost pollen onto Serena for my few successful germinations. The seedlings are not thornless, are sprawly a la Serena, and the one that bloomed had very double red blossoms. I see little path forward with them and might have dug them out. If I could get a reblooming form of Commander Gillette it would be fun to put that pollen onto Serena. Might try again this year…it’s really fun to pollinate Serena knowing that self-pollination is an impossibility…no need to emasculate.
Yeah, the 50 degree thing was something that David Zlesak has observed for polyanthas and others of multiflora heritage. I tried to keep my DE seeds at about 50 degrees, too, this year, but may have killed them with too much moisture or something.
Maybe combining your experience with DE and my experience with Serena means that I should attempt to pollinate DE again this year and maybe will get more germinations from the pollinated hips. I should probably root a cutting and get one started in a pot, as well, because I might be able to give the hips more ripening time and warmth with a potted DE.
Joe
Mike,
One grain of pollen does not always “do the trick”.
Variation of Animals and Plants vol. 2
Charles Darwin
With respect to plants, nearly the same results were obtained by Kölreuter and Gärtner. This last careful observer, after making successive trials on a Malva with more and more pollen-grains, found,14 that even thirty grains did not fertilise a single seed; but when forty grains were applied to the stigma, a few seeds of small size were formed. In the case of Mirabilis the pollen grains are extraordinarily large, and the ovarium contains only a single ovule; and these circumstances led Naudin15 to make the following experiments: a flower was fertilised by three grains and succeeded perfectly; twelve flowers were fertilised by two grains, and seventeen flowers by a single grain, and of these one flower alone in each lot perfected its seed: and it deserves especial notice that the plants produced by these two seeds never attained their proper dimensions, and bore flowers of remarkably small size. From these facts we clearly see that the quantity of the peculiar formative matter which is contained within the spermatozoa and pollen-grains is an all-important element in the act of fertilisation, not only for the full development of the seed, but for the vigour of the plant produced from such seed.
14 ‘Beitrage zur Kenntniss,’ &c., 1844, s. 345.
15 ‘Nouvelles Archives du Museum,’ tom. i. p. 27. 1865
I disagree with Darwin’s interpretation, though. I think it is a maternal response. A plant with numerous flowers does well to invest more resources into well pollinated flowers, rather than in those that get only a grain or two.
Mike, my setigera serena x mutabilis was a germination from last year, and it is still too small for material. I don’t know that it will have pollen to offer when the time comes – my impression is that the likelihood favors a dioecious female. I expect another 2 years before it blooms regardless. If it grows enough, I might be able to offer a cutting before then.
Glad to hear you got a setigera serena! David Z. proposed synstylae seem to be the most compatible matches. I know of no other American native synstylae, alas, which might offer as much inherent resistance to RRD, but multifloras being prone, I had wondered about trying e.g. multibracteata and/or some of the other synstylae more readily available in commerce. I wish I knew the relative resistance of the various species.
David had also offered that setigera offspring tend to have panicles of flowers arranged in a more flat arrangement – almost corymb-like, I suppose one could say.