Known CMS cultivars

[triffid]

Knowledge of which F1 cultivars carry cytoplasmic male sterility is particularly useful to those using commercial material in their brassica/allium/umbellifer breeding projects. This information isn't always easily accessible, so perhaps this topic could serve as an invitation to list which cultivars are known CMS lines.

[Joseph Lofthouse]

I assume that all commercial F1 hybrids of brassicas, alliums, and umbelifers carry CMS.

Brassica hybrids can also be made through self-incompatibility, but who would be willing to invest in the resources of labor, and materials to do it that way? Especially when CMS hybrids can be grown in an open field.

[Steph S]

Is it not the case that a gene to restore fertility is also used to neutralize the CMS?
So, the female parent carries the CMS and does not produce viable pollen, but the fertility restoring gene is contributed by the male parent?
I suppose there might be reasons for omitting or including the fertility restoring gene, depending on the crop.

It's a good question, and worth researching to find out the answer.

I don't often grow F1s.  In the case of Blues Napa cabbage, they bolted and readily set seed in isolation from any other brassicas, and the F2 generation were very self fertile as well, with nice fat pods in abundance and 100% or close germination rates.  So if CMS was used to produce the F1 seed, it was completely neutralized by another gene.
I don't know if restoring fertility is common practice in brassica crops.

[Joseph Lofthouse]

Is it not the case that a gene to restore fertility is also used to neutralize the CMS?
[...]
I don't know if restoring fertility is common practice in brassica crops.

The fertility restoring genes, if they exist, are closely guarded trade secrets. In any case, why would I want to grow a crop with defective cytoplasm? In the case of broccoli for example, the defective cytoplasm DNA is from a radish.

In the case of any crop that is eaten as a vegetable, there would be no reason to provide the restorer genes to the farmer.

[Steph S]

Hmm yes, but there is a reason according to this recent paper 2022:
2022:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9409259/
"The Ogura cytoplasm has been introduced into different Brassica crops, including B. napus (AACC), B. oleracea (CC), B. rapa (AA) and B. juncea (AABB), by intergeneric hybridization, somatic hybridization and repeated backcrossing. In rapeseed, it is essential for the Rfo restorer gene. In vegetables, because the leafy organ is used as a product for consumers, it is not necessary for fertility restoration to be possible in the vegetative growth stage. However, the wide usage of Ogura CMS has led to a new problem: all offspring not carrying the fertility-restored gene exhibit MS, which has inhibited germplasm innovation and breeding. Therefore, there is an urgent need to create a fertility restorer to promote the innovation and reutilization of germplasm resources in all Ogura CMS Brassica vegetables.  Corresponding restorer lines have also been successfully created in crops such as B. napus (AACC), B. oleracea (CC) and B. juncea (AABB)."

WRT the B rapa napa cabbage:

"Although Ogura CMS Chinese cabbage has been developed over a long period, it is generally believed that the lack of excellent Ogura CMS Chinese cabbage varieties with good economic traits and large-scale production is due to the problems of disease resistance, poor combination ability, low yield, negative cytoplasmic effects and the severe degradation of backcross generations despite some progress in addressing the problems of yellowing and nectary development. In addition, restorer lines of B. rapa have not been created or reported."

So it appears that CMS chinese cabbage is not marketable due to defects.
I wonder if Blues is marketed as F1 although it really isn't? Or is there a method of F1 seed production without CMS.

 Also since there are no restorer genes for B. rapa, you can pretty well expect that any F1s are either sterile or non CMS.  That would apply to turnip, rutabaga and others in this group.
Edited to add: The lack of restorer genes for B. rapa appears to be untrue - the paper linked below discusses turnip "MF" Maintainer Fertile and CMS lines in China:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6568414/

I had a volunteer brassica that overwintered one year and produced copious flowers but not a single seed - it might've been an F1 turnip (although I don't grow them, I've seen other vegs turn up in the manure).

[Joseph Lofthouse]

Brassicas are generally self-infertile, therefore, if you grow exactly one plant, it cannot pollinate itself and won't produce seeds.

Because of the self-infertility, brassica hybrids can be made by growing exactly one plant of each parent in isolation. They can be isolated either through distance, or by isolating the two plants inside a cage. Then you have to introduce pollinating insects, such as flies, into each cage.

It might also be possible to create hybrids by applying a poison to the plant that kills the pollen.

[Steph S]

Right you are Joseph.  B. rapa in particular, now I recall, - the flowers are self infertile.
But you can still get pollination between different flowers on the same plant.
Isolation would do it though - greenhouse production of seed and manual pollination between two parents.
That would explain the high price for 50 seeds in a packet.

[Steph S]

In the case of carrots, petaloid CMS is the most commonly used, probably in most F1 carrots.
"Tendersweet" is a variety with 'brown anther' CMS.  The Maintainer genetics is complicated for brown anther and makes it more difficult to create Maintainer lines for F1 carrot seed production.

Pics of petaloid CMS flower vs its Maintainer line with normal flowers, scroll down:
https://www.nature.com/articles/s41598-019-53717-x
 

[Klaus Brugger]

In Europe, FiBL (Research Institute of Organic Agriculture) publishes a positive list of "cell fusion free" vegetable varieties of brassicas, chicories, and root parsley that is binding for producers of certain organic farming associations.
"Cell fusion free" doesn't necessarily mean "CMS free", but in these crops it generally does, I think.

https://www.fibl.org/en/shop-en/1179-cf-free-varieties 

[Steph S]

Just reading more about this, since I'm pretty ignorant on the topic.
The CMS that occurs naturally in carrots, beets and others is widely used in F1's but is not a threat to diversity since the maintainer genes also occur naturally and are present in the F1, so entirely available. The CMS can be avoided simply by taking no seeds from the hybrid mother plant.  Pollen is viable due to presence of dominant fertility restorer gene in the F1.

Cell fusion CMS is described and commented here, with particular concern about brassicas:
https://efao.ca/cell-fusion-cytoplasmic-male-sterility/

And several other methods of CMS are described at the end of this publication, as well as the companies that developed certain proprietary methods of CMS: examples detailed are in corn.

https://iastate.pressbooks.pub/cultivardevelopment/chapter/new-line-development-and-new-line-evaluation-single-cross-hybrid/
Mumm, R.H.  (2023). New Line Development and New Line Evaluation Single-cross Hybrid. In W. P. Suza, & K. R. Lamkey (Eds.), Cultivar Development. Iowa State University Digital Press.

WRT brassicas in particular, I read several comments about Hakurei turnip F1 producing no viable flowers, but I also found some ongoing work at Fruition Seeds using Hakurei F1 as a parent:
https://www.fruitionseeds.com/learn/blog/cultivating-curiosity-cultures-of-care-breeding-turnips-beyond/

So there are F1 turnip seeds available that don't have CMS.
There are still companies that produce their B. rapa F1 seeds old school, using self incompatibility and isolation.   It seems that the bigger companies, more invested in genetic modification tech, are the ones likely to produce by cell fusion CMS or other forms of CMS without genes for fertility recovery.