incompatability systems

I picked up a ‘throw away’ mini-flora a few months ago that is from the Patio Hit series of Poulsen. I think that it is the rose Farourite, but the tag was short on details. It will not set hips. Just for kicks I decided to pollinate it with Party Girl and it is setting hips. So I am concluding from this that the rose has a functional self-incompatability system and I’m guessing that it is the sporophytic type rather than the gametophytic type. I have not come across much information on these types of SI systems in roses. I did find a paper by Y. UEDA and S. AKIMOTO Cross- and self-compatibility in various species of the genus Rosa. Journal of Horticultural Science & Biotechnology (2001) 76 (4) 392-395. But the paper was not all that informative, other than suggesting that SI breaks down with polypoldization. Anybody have any info or insights into the SI systems in tetraploid roses?

Google Scholar lists which papers cite a specific paper. The Ueda and Akimoto paper was referenced by six papers:

http://scholar.google.com/scholar?hl=en&lr=&q=link:CYPNS-Ggn3AJ:scholar.google.com/

Link: scholar.google.com/scholar?hl=en&lr=&q=link:CYPNS-Ggn3AJ:scholar.google.com/

Most links lead only to the abstract; the following link gives me the full paper:

http://www.plantcell.org/cgi/content/full/16/suppl_1/S72

Let me know if the link does not work for you.

Link: www.plantcell.org/cgi/content/full/16/suppl_1/S72

Roses have a gametophytic SI system. There is no evidence I have seen that anything in the Rosaceae family has a sporophytic system. Female sterility or nearly so is common in many modern 4x roses and I believe has more to do with other factors than SI. Lack of a decent hypanthium to support fruit development is one factor I notice in some cvs. In addition, there are a lot more male gametes than female. Even with the same fertility rate for male and female gametes, one can have a better chance at successfully using a low fertility parent as a male because of sheer numbers. Sincerely, David

Yeah, I guess that GSI would also give you complete sterility. While I have this topic started, any evidence of male sterility in roses?

Liz

Male sterility example:

Miniature rose plant named “Jacrepor”. Zary, Keith W. (Jackson + Perkins Wholesale, Inc., USA). U.S. Plant Pat. (2004),

Patent Family Information

Patent No. Kind Date Application No. Date

US 15019 P2 20040713 US 2002-300572 20021119

Priority Application

US 2002-300572 20021119

Abstract: "Miniature rose plant having high petal count of flowers of stable, red color; long shelf life as a pot rose; absence of pollen; and its ability to grow well on its own roots. "

Hi Liz, I’m not sure what you mean by GSI giving complete sterility. It is a system where proteins produced by the gamete interact with proteins in the style. If the S alleles are the same for what segregated to the pollen as is in the female the pollen tubes are often hindered- grow more slowly and may rupture. Warm temperatures, early or late pollinations, cutting the style so travel distance is less are all ways which a GSI can be circumvented. The pollen actually germinates and pollen tubes grow, unlike the sporophytic system where germination of the grain is typically inhibited. A GSI system tends to be more “plastic” and leaky. A GSI system typically in roses is active in diploid species. If one chromosome doubles the plants to make tetraploids the system breaks down somewhat and selfing can occur more readily. I found this with my chromosome doubled polyanthas. THere is evidence that what actually happens is that the pollen grains which segregate for two different SI alleles are the ones actually getting through and the others are not. So if we start with a diploid rose with two S alleles, say S3S5 and chorosome double the plant we will have S3S3S5S5. So if the reports are accurate, the pollen grains which segregate for S3S5 can produce pollen tubes which grow well enough to readily form selfs, but those that are S3S3 or S5S5 do not typically make it.

Yes, there is male sterility in roses and in particular in R. setigera, the only dioecious rose species. There are plants which are functionally only male and some functionally only female. I am working on determining the inheritance of gender in this species, but need more time and data before I can confidently develop a good genetic model which fits with the segregation patterns.

Sincerely,

David

Many plants have a self incompatibility system that has variable strength. Ultimately allowing self pollination if no compatible foreign pollen has been met.

Another possibility is that the incompatibility genes may mutate: making cross pollination possible within a single self sterile individual. This has been shown for large isolated intertropical trees. A clone is comparable to a tree.

Pierre Rutten

Yeah, my experience with incompatibility is in maize where it is basically a pollen competition issue. Both alleles are present in the progeny, but there is considerable segregation distortion. I’m quickly discovering that roses are not maize when it comes to genetics and breeding for that matter, too.

Liz

Have you looked at http://3e.plantphys.net ?

A companion site to a textbook, you can look up Topics, Essays, and Readings with each containing interesting material along with substantial and surprisingly current references. I

Sorry 'bout that - posted reply in the wrong spot - see mitochondria…