Brassica juncea x B. napus cross

[farmermike]

This plant appeared near a row of Giant Red Mustard (B. juncea) from a seed crop I saved in 2010. The seeds had spent the past 5 years in a storage unit until I rediscovered them last winter. It seems to have characteristics of the red mustard and Red Russian Kale (B. napus), or maybe rapini (B. rapa). It is likely I was growing both of those in 2010.



It has both the sweetness and mild bitterness of the Russian kale AND the spicy, mustardy flavor of the red mustard. It has the whitish green ribs and purple veins of the mustard, but the thick succulent leaves of the kale. The red mustard behind it in the photo is all in full flower, but this plant seems to be in the same stage as my spring planted russian kale. I really like this one!

So, I need some advice on how to attempt to continue this line. Anyone have experience growing out a cross like this? There is only one plant, so will it be able to pollinate itself and create a population from a single plant, or should I try to get it to back-cross with my Russian kale?

[steev]

I don't know, but it sounds worth preventing further crossing at the moment; at the least, I'd prevent any likely crossers from flowering in the area.

[steve1]

farmermike Brassica''a often have self incompatibility in mature flowers- effectively meaning they only outcross. You can overcome this by doing bud pollinations, it's what commercial breeders do to develop inbred lines. Hope that helps.
Cheers
Steve

[farmermike]

Well, my B. juncea x napus hybrid is about to start blooming. Thanks for the bud pollination suggestion steve1. I can't seem to find any explanations of how to actually do bud pollination on brassicas. Is it just a simple as: open the bud before it opens naturally, then transfer pollen from the stamen to the pistil? Can anyone point me in the right direction?

I found this article about hybrids between these 2 species. Apparently, the F2 generation tends to contain a high percentage of B. juncea type plants. They seem to be most interested in transferring agronomically useful traits between species. My primary interest in this F1 plant, is the unique flavor. It is basically like a Russian kale with a spicy, mustardy flavor. I could eat a lot of this!

The plant is very stocky, and has new shoots growing from the base, in addition to the apical inflorescence -- so I may have more than one shot a getting seeds. It is also blooming in perfect synchronicity with my Western Front Russian kale, and it is very tempting to just let that cross with my hybrid -- particularly if F2 segregation tends towards B. juncea types.

If I can ever manage to stabilize this phenotype, I may have something to pledge to OSSI -- but I won't know for a while.

[steev]

You may be stuck producing F1 seed, to get the particular flavor you like.

[farmermike]

I would be satisfied if I could just get a diverse population that produced some small percentage of this phenotype. Of course, I don't understand brassica genetics well enough to know if that is possible.

At any rate, in the future I will try to plant my B. napus and B. juncea crops together in hopes of more hybridization. The problem is getting them to bloom together. My spring planted juncea bloomed in late May and the napus is just starting now.

[steev]

Adjust planting dates?

[ilex]

You could try a few root cuttings

[ilex]

If you have other flowering brassicas, it's time to practice bud pollinization.

[steve1]

farmermike - yes open the immature flower and dab on mature pollen.
You could also do some pollinations on mature flowers by cutting the stigma and dabbing the pollen directly on the style. Both ways bypass the self incompatibility mechanism. One way or the other you should get seeds. Plant them together next year and let them pollinate each other in isolation and let those plants of the type you are after cross together. That should work... Because of the small size (guessing) of the flowers cutting off the stigma on mature flowers with small set of nail clippers or like might be easier than trying to open buds. Let us know how it goes.

[farmermike]

Aug 24, 2016 17:00:06 GMT -5 steve1 said:

farmermike - yes open the immature flower and dab on mature pollen.
You could also do some pollinations on mature flowers by cutting the stigma and dabbing the pollen directly on the style. Both ways bypass the self incompatibility mechanism. ...cutting off the stigma on mature flowers with small set of nail clippers or like might be easier than trying to open buds.

Thanks for the advice! I'll definitely try both methods.

ilex, good idea. This plant is sprouting some basal shoots, so I should be able to also propagate it vegetatively, just like people do with Daubenton.

steev, right, maybe if I plant more B. napus in the fall, and B. juncea in the spring, I could get them to flower together and possibly produce some more hybrids.

Or get some juncea with CMS and get all hybrids...haha!

[oxbowfarm]

Jun 9, 2016 11:47:03 GMT -5 farmermike said:

This plant appeared near a row of Giant Red Mustard (B. juncea) from a seed crop I saved in 2010. The seeds had spent the past 5 years in a storage unit until I rediscovered them last winter. It seems to have characteristics of the red mustard and Red Russian Kale (B. napus), or maybe rapini (B. rapa). It is likely I was growing both of those in 2010.



It has both the sweetness and mild bitterness of the Russian kale AND the spicy, mustardy flavor of the red mustard. It has the whitish green ribs and purple veins of the mustard, but the thick succulent leaves of the kale. The red mustard behind it in the photo is all in full flower, but this plant seems to be in the same stage as my spring planted russian kale. I really like this one!

So, I need some advice on how to attempt to continue this line. Anyone have experience growing out a cross like this? There is only one plant, so will it be able to pollinate itself and create a population from a single plant, or should I try to get it to back-cross with my Russian kale?

It is highly possible that it will produce seed all on its own. Juncea has essentially zero self incompatibility and selfs heavily even in an open pollinating situation with lots of other plants flowering and lots of pollinators. If it is a napusXjuncea then seed set might be low, but I bet you get some seed, if you can protect it from the birds.

[steve1]

farmermike - it would be worth bagging some flowers for pure selfs too. One way or the other you should have seed to work with...

[farmermike]

Well, this plant finally started blooming. The first 50-100 buds aborted and dropped before ever opening....until yesterday.


It is interesting that on many buds the stigma seems to be already exserted well before the bud is open. I wonder if this means I don't even need to open up a bud to get mature pollen onto an immature stigma. Maybe this is how B. juncea manages self-compatibility -- as oxbowfarm suggested.

I have been attempting the some of the bud pollination methods recommended on this thread, but it makes me realize I need to get a little more prepared: with a good set of tweezers, magnifying glasses, and some kind of pollination bags. I had a bunch of flowers pop up on a patch of gai-lan, which is busy ripening seed, over the past few days as well. I'm removing these flowers, but I'm not too worried about them contaminating my junceaXnapus. Triangle of U suggests that B. oleracea is not likely to cross with juncea or napus.

[oxbowfarm]

Sept 11, 2016 1:02:38 GMT -5 farmermike said:

Well, this plant finally started blooming. The first 50-100 buds aborted and dropped before ever opening....until yesterday.


It is interesting that on many buds the stigma seems to be already exserted well before the bud is open. I wonder if this means I don't even need to open up a bud to get mature pollen onto an immature stigma. Maybe this is how B. juncea manages self-compatibility -- as oxbowfarm suggested.

I have been attempting the some of the bud pollination methods recommended on this thread, but it makes me realize I need to get a little more prepared: with a good set of tweezers, magnifying glasses, and some kind of pollination bags. I had a bunch of flowers pop up on a patch of gai-lan, which is busy ripening seed, over the past few days as well. I'm removing these flowers, but I'm not too worried about them contaminating my junceaXnapus. Triangle of U suggests that B. oleracea is not likely to cross with juncea or napus.

Looks very promising. My understanding is that B. juncea doesn't have a self-incompatibility system due to being an allopolyploid. This is true also for napus and carinata. I was recently discussing B. juncea crossing via email with Frank Morton and he felt that in his experience 75% of juncea seed is selfed even in his wild garden with abundant pollinators and in crossing blocks with other varieties available. I'd personally bet good money that many of those flowers will self without you having to bud pollinate at all. The one email conversation I had with Tim Peters about bud pollinating he said he just uses his thumbnail to open the sepals quick and dirty to expose the stigma, does not bother emasculating or any other manipulation.

I would just tag your pollinations, but I bet you get more seed from flowers you don't touch. I also wouldn't bother with pollination bags etc.