Brassica juncea x B. napus cross

[steve1]

oxbowfarm - I don't agree. There is plenty of publications to say there is SI and multiple alleles in B.napus link.springer.com/article/10.1007/BF00042617 There has also been versions of re synthesized napus with SI deliberately built in for hybrid seed production. My reasoning for a pollination bag or two was to see whether SI is present or not as it is a dominant trait in Brassica. But hearing and seeing the stigma is exerted leads me to wonder whether the line is protogynous which may complicate that further and may explain the bud drop of the first 50-100 flowers. The flip side is that most napus lines that aren't f1 hybrids are self compatible which I'm guessing is your knowledgeable sources points.
My point which I should likely have expressed better, is given the nature of the incomplete knowledge of the parentage the best approach I could think of for of ensuring self pollinations of a one off plant that could be difficult to re-create would be to bypass the possibility of SI being present. Hope that explains my thought process and advice.

[oxbowfarm]

Sept 12, 2016 5:03:57 GMT -5 steve1 said:

oxbowfarm - I don't agree. There is plenty of publications to say there is SI and multiple alleles in B.napus link.springer.com/article/10.1007/BF00042617 There has also been versions of re synthesized napus with SI deliberately built in for hybrid seed production. My reasoning for a pollination bag or two was to see whether SI is present or not as it is a dominant trait in Brassica. But hearing and seeing the stigma is exerted leads me to wonder whether the line is protogynous which may complicate that further and may explain the bud drop of the first 50-100 flowers. The flip side is that most napus lines that aren't f1 hybrids are self compatible which I'm guessing is your knowledgeable sources points.
My point which I should likely have expressed better, is given the nature of the incomplete knowledge of the parentage the best approach I could think of for of ensuring self pollinations of a one off plant that could be difficult to re-create would be to bypass the possibility of SI being present. Hope that explains my thought process and advice.

That is interesting. Its certainly not consistent with my experience, but I've mainly focussed on saving seed from napus kale, and most of that research seems to be with rutabagas and oilseed rape/canola. I also don't see it as very applicable to juncea which is frustratingly self compatible in every variety I've worked with. This is nice when you are trying to stabilize a line, but frustrating when you are doing crosses and do not wish to mess with hand pollinating or fussy things like pollination bags. I suppose it depends on your approach. In my experience, no matter the species of Brassica, allowing nature to take its course is the easiest way vs doing tedious manipulations (although I've played with bud pollinations etc.) My own attitude is that it doesn't matter if any derived seed is selfed or not. When farmermike grows out the seed he will select for his preferred phenotype. Does it matter if that preferred phenotype is the result of a selfing or another cross in the long run? My own attitude is that it does not, because farmermike is there to do the selection. Selection is the most powerful tool, all the other tricks and steps are just there to help focus that selection.

[farmermike]

Well, that juncea x napus cross finally croaked without producing any seed. I attempted the bud pollination while it was blooming back in September, but to no avail. Maybe it was self-incompatibity (and my pollination technique failed), but I suspect the bigger problem was that it began flowering in the midst of our late summer heat. We can easily have 100deg days May through Sept. My brassicas typically flower Feb-April and are done ripening seed by the start of our summer heat. Whenever any of my brassicas try to flower during the heat, they don't manage to ripen any seed.

I fully expected this plant to perk back up with the start of cool rainy weather last fall, but it never did. It was plagued by powdery mildew and perhaps other diseases all fall and winter. It was also in a spot that flooded regularly during our frequent deluges this year. I guess my mistake was planting the seed in March. Maybe if it had been fall planted, and gotten to vernalize early in its life, it would have flowered in April along with its brethren. B. napus and oleracea perennialize in my garden pretty reliably, but juncea never does; I guess those juncea genes won out.

Oh well, easy come easy go! I'll have to try to get another one of these crosses to take. It sure had an interesting flavor.

Thanks for the suggestions and discussion, steve1 and oxbowfarm!

[walt]

You mentioned earlier that you could remake the origional cross in quantity using CMS.  It appeared you meant it as a joke, but it is an option. 
Another option is to try to get your B. juncea and your B. napus to bloom at the same time every year, so you might have a few of these hybrids every year.
Or you might try to save pollen from the eariier blooming parental species and hand pollinate a plan tof the later blooming parent.  That might not be too hard,
Your  hybrid had genomes AABC where AA is B. rapa, BB is B. nigra, CC is B. oleracea, AABB is B. juncea, and AACC is B. napus.  your AABC hybrid would have had low fertility, I don't know how low.  But that accounts for some of the failure to set seeds  It is usually better to lear to make crosses with plants with good fertility.  Then you find out quickly if you are ding it right.
I have read, years ago, about someone making AABBCC allohexaploids.  I would expect it was nothing like your AABC plant because of the great diversity in each of the Brassica species.  But if you could aquire, or make, an AABBCC plant, then it might cross with you AABC, and might give a fertile strain of these AABBCC that was similar to yours.  
This isn't just idle chatter.  It seems like a worthy challenge for me.  Could you spare some seeds of your B. napus and B. juncea?
The AABBCC plants I have read about were of no garden value, but maybe that was due to just using any handy AA, BB, and CC.
Also an option.  Doubling an AABC seedling to get AAAABBCC.  That's a lot of chromosomes and one wouldn't be guaranteed fertility, even viablity.  But it might work.


Yes, I saw that the triangle of U shows AABB X CC, BBCC X AA, AACC X BB are all impossible.  But how impossible?  The tringle was published in 1935.  A lot of things were impossible then.

[walt]

www.australianoilseeds.com/__data/assets/pdf_file/0007/6874/26_An_alternate_procedure_for_resynthesis_of_B._juncea.pdf

This paper says that octaploid Brassicas tend to lose chromosomes, especially chromosomes from the genome with 4 sets of chromosomes. In other words, if AABB X AACC gives AABC, and that is doubled to AAAABBCC, in as little as 2 generatios, it can drop to BBCC. Truely strange. Now that is with selection for BBCC. The paper doesn't say what happens if you select strogly for the octoploid type.
But it does cast doubt on the possibility of stablizing this hybrid by doubling chromosomes.

[steev]

Damn, walt! So informed; respect!

[walt]

First thing I do when I get an interest in something is google and see if someone already tried.  Saves a lot of time in the long run.
Still this seems like an interesting project.

[farmermike]

Thanks for all the info, walt. Very interesting! It would be great to see if you could make a cross of these two species. I may indeed try making the cross again using one CMS parent -- if nothing else, just to train my eye at recognizing the phenotype of the hybrid.

I would be happy to send you some of my seed stock. I have plenty of the B. juncea (Giant Red Mustard). Some of it was saved in spring 2016, but I also still have seed from the 2010 batch the produced the original hybrid last year (it still had near perfect germination in Feb 2016). I have less B. napus, but still happy to share. I have a little seed from a single plant of Western Front Kale that flowered without vernalization last year (the rest of that sowing didn't bloom until this spring -- and produced no seed due to aphid epidemic). I also have enough to share from the original packet of Groninger Blue Kale (Fertile Valley Seeds 2016). Let me know and I'll get some in the mail for you.

That Groninger Blue, by the way, is a very interesting variety. It is touted as B. napus, but it is very different from any other napus kale I have grown before. Based on flavor and growth habit, I am inclined to wonder if it is B. napus backcrossed to B. rapa. (Would that make it AAAACC?) I guess that would make it like the Gilfeather Turnip. Or maybe the GB is just descended from Rutabaga stock (B. napus), but bred for leaf production instead of root -- which are also very different from most napus kales. 

[bajes94]

That's impressive, that that happened. I am an amateur so take what I say with a grain of salt. You could recreate the cross with two other plants and then cross-breed these plants together and then select plants from the resulting population. I would think that would be the most surefire way to maintain that cross but I am not an expert. If you think that is a decent idea go with it but some of the other answers seem better so go with those first.