Help explain mini rugosa?

I crossed Rosa rugosa ‘Rubra’[/url] with ‘Ferdinand Pichard’ in 2000. Of the approximately 300 seedlings that germinated all the leaves looked intermediate between rugosa and FP except for three seedlings. These seedlings had very rugose and quite tiny leaves. These seedlings were quite slow growing, and one died in the first month, another in the first year. The third, after three years of growth, is only 15 inches tall, and opened it first flower[/url] this week. This rose looks mostly like a miniature ‘Rubra’ except for the narrower leaves.

The thing that confuses me is this rose seems nothing at all like FP, yet I’m sure I opened the bud and removed the anthers from ‘Rubra’ long before it could be shedding pollen. The flower was always covered except for when I actively applied pollen. I’ve read that plants can sometimes divide in such a way that they produce a viable seed without pollen, but shouldn’t that then produce a plant almost identical to the mother? Why is this rose so small? There are no miniatures anywhere in its geneology.

Any guesses as to what quirk of genetics produced this rose?

Here is a picture of the whole plant[/url] as well as a comparison of parent and child leaves[/url].

P.S. I have a nagging memory of reading of someone else who did a wide cross with rugosas and got tiny and slow growing seedlings, but I can’t recall. Does it ring a bell for anyone? Maybe it was R. rugosa x R. arkansana?

The very small OGR Pompom de Bourgogne has narrow little leaves. Perhaps FP has something similar in its ancestry.

I had a very small rugosa that survived the first summer outdoors but was dead the next spring.

I have had several Theresa Bugnet granddaughters or great granddaughters similar to yours in size. One had very nice double flowers ( http://home.neo.rr.com/kuska/Theresebugnetdaughter.htm )

Its offspring is http://home.neo.rr.com/kuska/theresabugnetgranddaughterleft.htm

and http://home.neo.rr.com/kuska/tbugnetoct.htm

and http://home.neo.rr.com/kuska/ThereseBugnetGDXWILLALDERMAN.htm

The following is one where the great granddaughter was used as the pollen parent:

Http://home.neo.rr.com/kuska/hansaX32.htm

These are 2 to 3 foot plants; but other offspring were 7 or 8 foot plants. I have other plants from the same mother that do not appear to have any rugosa blood in them (both large and small).

Eric, I got some miserable runts from R. rugosa using R. eglanteria pollen. Took quite a few years to bloom, and those blooms weren’t worth waiting for. But unlike your seedling, I could see definite traits from the eglanteria. The seedlings were not so similar to the rugosa parent. I don’t know if roses have ever been documented to do this, but the first idea that popped into my head was that your seedling looked like what I’d imagine for a haploid rugosa. I know some other plants will make haploid offspring when crossed to a distant relative, but most of those examples (that I know of) are in the grass family. I’ve seen pictures of haploid tobacco (I think) and some other dicots, that have been grown from anther culture. They have that same diminutive appearance. Just food for thought. Tom

Haploid roses were grown in southern France by INRA (Agricultural Research National Institute). They got as well dihaploid (that is diploids from tetraploids) roses. The later from irradiated (dead) pollen are being further bred with success. The curious is that with the expected diploid progeny they got aneuploids, triploids, tetraploids and pentaploids.

About Eric’s rugosa seedling if fertile it is probably an unwanted cross. If sterile aneuploidy or haploidy are possibilities.

Friendly yours.

Pierre

Hey, that looks interesting! It looks like it might be fun to work with crossing it back to fertile mini seed parents.

Jim