Brassica oleracea crosses

[farmermike]

Does anyone have experience growing out crosses between very dissimilar B. oleracea varieties? I know there are crosses between broccoli and kale, or broccoli and cauliflower, but what about cauliflower x cabbage, broccoli x Brussels sprouts, or kohlrabi x anything? Am I likely to end up with anything useful?

Right now in my garden I have broccoli that is almost done flowering, Brussels sprouts that are just starting, and just a few cauliflowers that are at their peak of florescence. I imagine there are a few crosses between the broc and cauli, but I'm trying to decide if I should nip the last few broc flowers before the brussels really get going.

A couple of the cauliflowers are male-sterile Graffiti F1 that have a few seed pods ripening, so I guess I'm guaranteed some crosses there.

Any thoughts would be appreciated. Thanks!

Mike

[philagardener]

Kale x Brussels Sprouts is an interesting combo. www.kalettes.com/ Lots of little heads along the stem. Certainly worthy of a little experimentation, farmermike !

[farmermike]

Good point, philagardener. I hadn't heard of those.

Brussels sprouts that grow a bunch of little broccoli or cauliflower heads along the stem, instead of sprouts,  would be pretty cool. But if it was possible, I imagine someone would have done it already.

[steev]

That's what they said about flight, 150 years ago.

[rowan]

My Fulstaff brussels sprouts do this. I sell the little 'flowers' in punnets and people love them. Pity they are so small though so a larger sprouted type that also does this would be a seller I think.

[robertb]

I've got Dorbenton's x broccoli crosses. So far they're acting like normal broccoli; the crucial thing is whether they're truly perennial. I'm going to let them flower uncropped to put them under the maximum stress, and see what happens.

[farmermike]

Mar 18, 2016 13:19:18 GMT -5 rowan said:

My Fulstaff brussels sprouts do this. I sell the little 'flowers' in punnets and people love them.

It turns out some of my Catskill Brussels sprouts did this to. They didn't make any real sprouts, but only little loose ones. I had thought they were a total failure, but after reading this I tried one and it was really tasty!

[reed]

I'v had sprouts do that a lot. They often grow the little loose ones after the others have been harvested. Unfortunately I have never been able to get seeds from anything other than broccoli, most kinds I'v grown act like annuals here. I'm hoping to cross other things with it and make them annual too, I don't care what they look like or what kind of heads they make. I like leaves, stems and stalks of a lot of brassicas as well or better than what ever they are traditionally grown for.  

[farmermike]

Mar 18, 2016 11:45:12 GMT -5 farmermike said:

Brussels sprouts that grow a bunch of little broccoli or cauliflower heads along the stem, instead of sprouts, would be pretty cool. But if it was possible, I imagine someone would have done it already.

Well, I guess I spoke too soon. The mother of this plant was Sunset F1 cauliflower, which is male sterile. The father was presumably a Brussels Sprout.


From the top it looks pretty much just like Collard Greens.


From the underside you can see that, along the stem, it has a bunch of little sprouts that each have a little cauliflower head growing from the middle.

I generally cull CMS from my garden, but it sure is an easy way to see what wide crosses within B. oleracea will produce. I won't include CMS germplasm in any of my landraces (primarily because I want to share seed with other landrace gardeners), but I will admit that I'm not entirely convinced that it would cause any detriment in a Brassica landrace. I had previously presumed that the presence of CMS, within a population, would result lower seed production, but this Sunset F1 (flowering alongside Brussels Sprouts and Broccoli) produced a tremendous amount of seed. It seems that it would actually increase the rate of outcrossing, although that might be totally unnecessary in species that are generally self-incompatible. Are there other potentially detrimental results CMS could produce? In any case, I may keep playing with a few CMS varieties for educational purposes. It makes it so easy to test wide crosses -- without needing to do any bagging, tagging or hand pollination.

If nothing else, this experiment has inspired me to try crossing some fully fertile cauliflower and Brussels sprouts, and see if I can stabilize a strain similar to the specimen pictured above.

[reed]

That is a pretty nifty looking plant.

I'm afraid of CMS cause I don't want it's seeds volunteering. It is interesting though in how it can tell you for sure that you had a cross. I hope to achieve the same basic thing just by alternating plants. Each sprouts plant for example is next to a cabbage or broccoli on each side instead of another sprout. Bees tend to make their way methodically from one flower to another so I figure there's high probability of crosses. I'll just wait till following seasons to see what turns up. My next step is to almost immediately replant mature seeds and see what lives through winter. A thorough mix up of genes is the goal at first then winter survival is my first selection criteria, I'll look at other specific traits later.

[Joseph Lofthouse]

I was growing carrots that were 70% male sterile. They grew fine, and made seeds fine.

I choose to have fully functional flowers on my farm, but there isn't any reason that amateur plant breeders couldn't be making hybrids by using CMS.

[reed]

I just don't like the notion of CMS. An unnecessary complication. It might be good for making specific hybrids but if I remember right it is inherited from the mother's side. I think that could mess up a continuously evolving and sustainable landrace pretty quick.

I'm not interested in doing it but out of curiosity. If you need to continuously maintain two distinct inbred lines for use in making a particular hybrid each season, how do they maintain the pure CMS inbred strain?

[philagardener]

To keep generating a hybrid a company maintains two parental inbred lines that are crossed to make the genetically uniform, heterozygous F1 seed. The identities of those lines often are a deeply held secret, since a competitor would need to know/have those to make the product.

Great question about the CMS maintenance. The CMS female parent typically is generated by taking an OP, self-fertile line and crossing in the cytoplasmic sterility trait; this is then back-crossed repeatedly to the original line (over about 7 generations) to generate a CMS line that is virtually identical in other respects to the original OP line. The female parent plant is the one that passes on the CMS trait, so it is pretty straightforward (but takes time, one reason that GMO approaches appeal to BigAg as that could be accomplished in one generation).

Then the CMS line can be maintained indefinitely by crossing to the original non-CMS line; all of the seed from the CMS parent will have the CMS trait (and all of the seed on the pollen parent would not, so both versions can be maintained in adjacent blocks to keep both lines going).

[reed]

So you have for example, OP cabbage (A) you use it for pollen on CMS cabbage (B). The CMS seeds from (B) are pollinated again with OP (A) the following season and so on until there is little left of CMS (B) except for the CMS part. So now you got CMS (C), is nearly identical to OP (A) which can be maintained indefinitely and you can easily cross it to any other OP and make a new proprietary hybrid? Interesting.

Where did the original CMS come from? Does it naturally coexist in plant populations?

[philagardener]

Nature is full of all sorts of incompatibility systems, CMS among them. Many male sterile traits emerged by natural mutation and were noticed and studied by botanists (including Darwin, who was fascinated by plant reproductive biology). It can get a lot more complicated (nuclear restorer genes, etc) but that is a simple and direct way to think about it.

CMS also can happen in some interspecific crosses because of coordination issues between nuclear and cytoplasmic (mitochondrial and/or chloroplast) genes that affect pollen formation. There are high tech approaches that mimic this natural process to make CMS lines by using somatic cell fusion to transfer incompatible cytoplasm into a line in a single step.