R. palustris ploidy

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matt lustig
Posts: 42
Joined: Sat Jan 28, 2017 10:05 pm

R. palustris ploidy

Post: # 65927Post matt lustig
Sun Jul 02, 2017 1:03 pm

I understand that there are diploid and tetraploid members of R. palustris. Do we know whether these ploidy levels are distinct geographically? For instance, in an entirely different group of plants (Chelone, a genus of wildflowers), the literature documents that one of the species has distinct ploidy levels separated by geographically. Presumably there is a thin line of contact where the different populations meet, but their ranges are evidently largely distinct.

In R. palustris, I assume that whether the "varieties" are separated geographically or not, they must at least be somewhat reproductively isolated, since I presume that their triploid offspring would have limited fertility.

Anyone know of solid information (great if it is published) about whether the ploidy levels are separated geographically or mixed?

Karl K
Posts: 1340
Joined: Sat Jun 02, 2012 4:49 pm

Re: R. palustris ploidy

Post: # 65930Post Karl K
Mon Jul 03, 2017 12:31 pm

Matt,
I did some googling, but the only reference to tetraploid R. palustris specimens are on this forum. The original (?) was in the MN Landscape arboretum.
viewtopic.php?f=2&t=4668

Diploid species sometimes produce triploid or tetraploid offspring, but apparently these do not persist long in the wild except in special circumstances. E.g., a tetraploid might gain an advantage at high altitudes.

Newly formed tetraploids often suffer from reduced fertility due to irregular "pairing" of chromosomes during meiosis. Instead of the usual pairs, some groups of three or four chromosomes may become entangled. Resulting pollen grains or ova may have too many or too few chromosomes. After a few generations, however, this may get sorted out.

Rosa macrophylla var. Korolkowii is (or was) a tetraploid form of the species that was found in a garden.
http://bulbnrose.x10.mx/Roses/Rose_Pict ... kowii.html


Don
Posts: 1865
Joined: Wed Dec 31, 1969 7:00 pm

Re: R. palustris ploidy

Post: # 65935Post Don
Wed Jul 05, 2017 1:07 am

Palustris is an elusive critter - are you asking for edification or do you have palustris in hand?

You don't necessarily need a tetraploid palustris to get tetraploid pollen. You can dredge up discussions here on the fact that all roses make pollen grains having a variety of ploidy levels which can be distinguished from one another by their size.
What doesn't kill them makes them stronger.

matt lustig
Posts: 42
Joined: Sat Jan 28, 2017 10:05 pm

Re: R. palustris ploidy

Post: # 65942Post matt lustig
Wed Jul 05, 2017 11:11 pm

Don--Yes, I was specifically asking about the R. palustris that I have seen in the NY/PA region. It sounds like most or all of these specimens will be diploid, although I gather that rare tetraploid specimens may occasionally be present.

My own presumed R. palustris were collected (with permission) in the vicinity of Hanging Bog in Western NY. This autumn I hope to harvest palustris x 'Iceberg' (which I understand to be a triploid with some fertility as a pollen parent) seeds from an initial cross.

Regards,
Matt

henry kuska
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Joined: Thu Dec 15, 2011 9:06 pm

Re: R. palustris ploidy

Post: # 65943Post henry kuska
Thu Jul 06, 2017 12:11 am

Concerning Don's comment about pollen size:
http://rosebreeders.org/forum/viewtopic ... ter#p17228

Karl K
Posts: 1340
Joined: Sat Jun 02, 2012 4:49 pm

Re: R. palustris ploidy

Post: # 65972Post Karl K
Wed Jul 12, 2017 11:42 am

matt lustig wrote:My own presumed R. palustris were collected (with permission) in the vicinity of Hanging Bog in Western NY. This autumn I hope to harvest palustris x 'Iceberg' (which I understand to be a triploid with some fertility as a pollen parent) seeds from an initial cross.
Matt
Matt,
This item might be of interest to you:
RHA Newsletter 6(3): 8-9 (1975)
Persuading Reluctant Seed Bearers
George Sherwood

Sometimes, roses are reluctant brides. What can be done to ameliorate this reluctance?

In nature, when a plant is in danger of dying, or is in poor health, it will endeavor to reproduce in order to perpetuate the species. It is from here that we take our cue, and that is to make the plant struggle for survival.

Allowing long grass to grow up around the plant and creating competition works in some cases. In one township in New Zealand, I remember seeing just how roses should not be grown. In this case it was a small roadside area someone had evidently tried to tidy up, inasmuch as it was next to a major turnoff. A few roses had been planted in the lawn, and the grass came right up to the stems of the roses, with no cultivated area at all. Under these circumstances, it was safe to assume that the roses received no fertiliser whatsoever and no watering save when it rained. One of these roses was Iceberg, a poor and miserable specimen if ever I have seen one. Normally, Iceberg seldom sets seed; if it does, the seed count is very low. Well, here it was with more hips on it than I have ever seen for this variety, and I very quickly grasped the lesson that it taught me.
http://bulbnrose.x10.mx/Roses/breeding/ ... s1975.html
Karl

roseseek
Posts: 5156
Joined: Sun Dec 11, 2011 6:54 pm
Location: Zone 9b Central California, Sunset Zone 15

Re: R. palustris ploidy

Post: # 65977Post roseseek
Wed Jul 12, 2017 1:16 pm

When Joe Winchell found roses reluctant to set seed, he would pollinate them, then "root prune" by driving a shovel into the ground around the plant to sever the roots. It worked for him, but also resulted in a forest of Dr. Huey in his yard. Each severed root generated a new Huey plant! Stressing a plant often results in seed set. When times are good (sufficient rain, food, benign weather conditions) the rose simply grows to produce a good organism. Severely stress it, make it "think" it's going to die and it reproduces to perpetuate the species...if at all possible.
Kim
California Central Coast
USDA Zone 9b
Sunset Zone 15
Cooler inland coastal valley with strong marine influence

Karl K
Posts: 1340
Joined: Sat Jun 02, 2012 4:49 pm

Re: R. palustris ploidy

Post: # 65978Post Karl K
Wed Jul 12, 2017 3:21 pm

roseseek wrote:When Joe Winchell found roses reluctant to set seed, he would pollinate them, then "root prune" by driving a shovel into the ground around the plant to sever the roots. It worked for him, but also resulted in a forest of Dr. Huey in his yard. Each severed root generated a new Huey plant!
Yikes! A forest of 'Dr. Huey' is not something I'd care to have around.

Ringing is another method that has been successful with a wide range of plants. Here's an article about ringing grapes.
http://bulbnrose.x10.mx/Heredity/Husman ... g1920.html

And my bibliography on the subject.
http://bulbnrose.x10.mx/Heredity/King/Girdling.html

matt lustig
Posts: 42
Joined: Sat Jan 28, 2017 10:05 pm

Re: R. palustris ploidy

Post: # 65979Post matt lustig
Wed Jul 12, 2017 10:22 pm

Thanks so much for the interesting insights. Stressing the plant to promote seed production is an interesting idea. I have heard of a similar technique being used with an Oriental fruit tree called jujube (Ziziphus sp.), to increase fruit production. If I recall, in that case the trees were being partially girdled to stress them.

I also remember observing an (apparently) naturally stressed persimmon tree that was evidently close to death but also loaded with fruit. Good insight into the potential use of this phenomenon in roses.

Thanks,
Matt

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