Root sports

A meeting place for rose breeders.
Karl K
Posts: 898
Joined: Sat Jun 02, 2012 4:49 pm
Contact:

Root sports

Post: # 67809Post Karl K
Wed May 09, 2018 10:16 am

Root sports can be interesting and useful. For one thing, chimeras sometimes can be sorted out. Isolated genotypes or phenotypes are more easily used for breeding than the original chimera. E.g., a thornless blackberry turned out to be an ordinary thorny blackberry with a thin "skin" of a dwarf thornless type.

Then there are root sports that differ from the original in unexpected ways. 'New Dawn', for example, reblooms though its "parent", 'Dr. W. Van Fleet', does not. Both 'Happenstance' and 'Little Mermaid' are dwarf versions of the spectacular 'Mermaid'. (Has anyone seen both of these at the same place and time? It is curious that 'Mermaid' produced two dwarf root sports in California).

I mention these cases because I happened on an item in my old notes. I first mentioned it on rec.gardens.roses 12/4/1996.

In his 1959 ARA article, 'Roses Have Satellites, Too', Edward Risley wrote:
"N.H. #5425 (Skinner's Rambler x Yellow Pinocchio). A sterile triploid with 21 chromosomes. Only 33% of the cells examined had all 21: 4 had 20, 7 had 19, 6 had 18 and 3 had only 17."
American Rose Annual 44: 141-145

I can only wonder whether repeatedly raising a sterile triploid from root cuttings might eventually give rise to a diploid ... or something close enough to diploid to be reasonably fertile. And there's no telling what sort of sports might turn up with various chromosome numbers.

jbergeson
Posts: 1099
Joined: Thu Dec 15, 2011 11:54 pm
Contact:

Re: Root sports

Post: # 67817Post jbergeson
Wed May 09, 2018 9:39 pm

I wonder if there'd be any way to induce root sports.

philip_la
Posts: 857
Joined: Thu Dec 15, 2011 10:28 pm
Contact:

Re: Root sports

Post: # 67820Post philip_la
Thu May 10, 2018 12:55 am

I was wondering the same, Joe. I had a plant of Limoncello die to the ground during a drought/heatwave, only to return from the roots a year later. The first to emerge was a micro-mini (I called it Limoncellini) but other root parts soon followed and overshadowed the micro-mini. I tried to save the Limoncellini portion, but the root from which it emerged was ridiculously deep, and I was unable to successfully re-root the portion I removed -- it was summer again already, and the poor beast really resented the whole affair.
Philip F.
[size=small][color=#669966]Zone 8 / Sunset Zn 30 (Austin, TX -- formerly New Orleans, LA)[/color][/size]

Karl K
Posts: 898
Joined: Sat Jun 02, 2012 4:49 pm
Contact:

Re: Root sports

Post: # 67821Post Karl K
Thu May 10, 2018 5:03 pm

jbergeson wrote:
Wed May 09, 2018 9:39 pm
I wonder if there'd be any way to induce root sports.
Cells that had fewer than 21 chromosomes, if they could be regenerated into plants, should have differed from the original type in some way.

And now that I look at the numbers again, there seem to be some missing.

33% of the cells examined had all 21
4 had 20,
7 had 19,
6 had 18 and
3 had only 17.

Did he mean that 4% had 20 chromosomes, or 4 cells? If the latter, then he examined a total of 30 cells: 10 of them (33%) had the expected number of chromosomes.

Whatever it was, these could be regarded as sports.

Rob Byrnes
Posts: 1531
Joined: Thu Dec 15, 2011 2:34 pm
Contact:

Re: Root sports

Post: # 67851Post Rob Byrnes
Tue May 15, 2018 11:06 am

Hi Karl. I've discovered what I believe is a root sport of Therese Bugnet. The buds are light pink and the blooms open to a very light pink. The bloom form is very similar to Therese Bugnet. I'm trying to propagate the 'sport'. If this is a sport, it would be interesting to find out if the chromosome count might have changed.
Rob Byrnes

Historic Village of Roebling, NJ Zone 7a
On the right bank of the Delaware River

Don
Posts: 1744
Joined: Wed Dec 31, 1969 7:00 pm
Contact:

Re: Root sports

Post: # 67852Post Don
Tue May 15, 2018 1:14 pm

Then it must be possible to create graft chimera's by 'skinning' a piece of, say, Carefree Delight and replace the missing dermis tissue with some from, say, Tropicana. Would we not expect flowers from such a chimera to be structurally the same as those of Carefree Delight but orange in color instead of pink?

>> a thornless blackberry turned out to be an ordinary thorny blackberry with a thin "skin" of a dwarf thornless type.
What doesn't kill them makes them stronger.

Karl K
Posts: 898
Joined: Sat Jun 02, 2012 4:49 pm
Contact:

Re: Root sports

Post: # 67853Post Karl K
Tue May 15, 2018 8:02 pm

There was a Devoniensis over White Banksiae chimera back in the 19th century.
http://bulbnrose.x10.mx/Roses/breeding/ ... a1891.html

Then there's this:

Pakistan Journal of Biological Sciences 6(19): 1644-1648, 2003
ISSN 1028-8880 © 2003 Asian Network for Scientific Information
Separation of Thornless Rose Chimeras into Their (Rosa sp.) Consistent Genotypes in vitro
Fatih Au Canli and Robert M. Skirvin Department of Horticulture, Faculty of Agriculture, Suleyman Demirel University, Central Campus 32260 ISPARTA, Turkey 'University of Illinois at Urbana-Champaign, Urbana IL USA

Abstract: To isolate a pure thornless rose, a thornless sport of Rosa multiflora ('Fairmount 1') was established in tissue culture. To determine whether the sports were chimeral and consisted of both thorny and thornless tissue, the regenerants obtained in the tissue culture studies were assessed for the thorny or thornless condition both in vitro and ex vitro. Chimeral plants were expected to yield both thorny and thornless regenerants. Among these regenerants we expected to obtain a pure thornless rose. All tissue culture experiments with 'FM1' yielded both thorny and thornless regenerants, clearly demonstrating that 'FM1' is chimeral. TDZ significantly affected segregation both in vitro and ex vitro. The percentage of thorny plants was highest at 14.4 FM TDZ and lowest with control (0 FM TDZ). The linear relationship between increasing TDZ concentrations and percentage of thorny plants at vitro was significant. These results show rose chimeras can be separated into their component genotypes by growing them on media with high concentrations of TDZ (3.6, 5.4 7.2 and 14.5 FM TDZ). Also among 240 plants from the TDZ experiments, 21 plants were classified as thornless after a seven months in the greenhouse.
http://www.docsdrive.com/pdfs/ansinet/p ... 4-1648.pdf

Post Reply

Who is online

Users browsing this forum: Bing [Bot] and 6 guests