Clearing up the confusion on Brassica Cross pollination

https://www.redwoodseeds.net/blogs/the-story-of-seed/14200361-brassica-basics-seed-saving-101

"What is going to seed in our garden now? We have Red Winter Kale (B. napus), Collards (B. oleraceae), Pak Choy(B. rapa) and Giant Red Mustard(B. juncea) all going to seed. They all have the same genus but different species so there will be no cross pollination. Easy!"

Amit Enventres wrote:https://www.redwoodseeds.net/blogs/the-story-of-seed/14200361-brassica-basics-seed-saving-101

"What is going to seed in our garden now? We have Red Winter Kale (B. napus), Collards (B. oleraceae), Pak Choy(B. rapa) and Giant Red Mustard(B. juncea) all going to seed. They all have the same genus but different species so there will be no cross pollination. Easy!"

They can actually cross. I have had radishes and mustard cross in the garden before. I now plant them staggered so they won't bloom at the same time. In fact, crossing brassicæ is so easy that new species are coming to market all the time. One that comes to mind is misome, which is a cross between komatsuna and tatsoi. In Asia, there are hundreds of varieties of brassicæ which have mixed ancestry.

The brassicas are complicated. A wikipedia article details the relationships and crossability among common brassica species. Here's the image from that article.

I would be so grateful to anyone who could give me a bit more clarity here...from the diagram it looks like pretty much any brassica can cross-pollinate with other brassicas, is this deduction correct? For example, if I want to save seeds from turnips, cabbage, bok choy, and cauliflower, I should take measures to keep them from crossing (I guess with my small-ish planting area the best option is to stagger planting dates)? Or, in accordance with the landrace theory, would it really be that awful if some of the seeds cross-pollinated? Could I be so lucky as to come up with a turnip that gives cauliflower on top? Hehehe

I am dead-set on saving all of my own seeds but this is my first year and it seems a little overwhelming. Would love to hear anyone's experience or advice.

Some collaborators tell me they are saving mixed-heritage brassica seeds. They are selecting for highly edible leaves and flowers, and not worrying about specialized traits like kohlrabi shape, or cabbage heads. In other words, they end up with awesome tasting flowers, and often tasty leaves.  

In my own garden, I haven't seen interspecies hybrids. I haven't seen hybrids between turnips and bok choi, because they flower at different times. Kale/cabbage hybrids are common for me. I reselect for kale types.

I don't grow a lot of brassicas, because of the aridity of my climate most springs. By the time the irrigation is active, it is too hot for them to taste good.

Excellent info, thanks so much!!! I think very few people know when different plants flower, because we are so conditioned to harvest "when ripe" and we miss out on the full life cycle of the plant. I let my radishes go to seed this year, and they were some of the prettiest flowers in my garden! I never knew.

Is there a particular reason that I see lots of people on here selecting for kale characteristics over cabbage? Personal preference, or another reason? Seems like cabbage would be better for storage but maybe I am missing something.

P.S. just found another of your posts on a thread called "Preventing Cross-Pollination". Explained tons of things for me, I like the 95% purity standard--totally achievable. Now I'm armed and ready to Save All the Seeds!

In general, older, flat-leaf kales are more resistant to pest infections. They are much truer to the natural form of the species. Brussels, cabbages and even curly kales are relatively modern, bred to fill specific niches (for example brussel sprouts travel well to market, cabbages are well insulated and so don't freeze when left outside in the winter) but less hardy as a trade-off.

One way around this is that most types of seeds, including most brassicas, as far as I know, can easily last for 4 or 5 years if stored properly (cool and dry). So you can decide to let just one type flower at any given time, and then not let that type flower again until a few years later when you need more of that seed.  Also, if you let several individuals of one type go to seed, you are likely to get a lot of seed, enough for a few years.

The diagram posted here previously is interesting but I don't understand it exactly. It seems to mean that each species can cross with its two neighbors in the diagram, but not with the others that are more distant. Is that right?

Joseph Lofthouse wrote:Some collaborators tell me they are saving mixed-heritage brassica seeds. They are selecting for highly edible leaves and flowers, and not worrying about specialized traits like kohlrabi shape, or cabbage heads. In other words, they end up with awesome tasting flowers, and often tasty leaves.  

In my own garden, I haven't seen interspecies hybrids. I haven't seen hybrids between turnips and bok choi, because they flower at different times. Kale/cabbage hybrids are common for me. I reselect for kale types.

I don't grow a lot of brassicas, because of the aridity of my climate most springs. By the time the irrigation is active, it is too hot for them to taste good.

I can't say for sure if I have interspecies crosses or not, I have a lot of radish, turnip and mustard that has basically gone feral in my garden. The flower stalks and buds and especially the seed pods are what I harvest to eat, I select for mild flavored seed pods and crisp non-stringy stems. These species were very easy to adapt to this method. The mustard and turnips are perfectly winter hardy and now with introduction of what was described as "fall" radishes they are getting that way too.

For cabbage, broccoli, brussels sprouts and the like I failed several times in producing seeds. I tried to plant them in the spring, as traditional, and to keep the mature plants over winter, it didn't work.  I got the idea to start them in late summer or early fall instead and it has worked wonderfully. This year I have a large patch of this species currently maturing seeds. Unfortunately the seed pods, unlike radish and turnip are terribly tough and stringy but the flower buds and stems are amazing.  They tend to snap just at the point where the tender part ends are great raw or steamed. They have been producing since early march and no issue with the ubiquitous cabbage worms because it was too cold for them.  

I could have harvested a lot and I mean a lot, more of them but this  the first year of success and I had no idea how big they got (over six feet) or how many side shoots they would produce. Every time I picked one they grew a bunch more.

I didn't keep track of what plant was what but I think those most productive of the tender and tasty stems are Brussels sprouts. Also those with a lot of purple are the most delicious.

I also have feral kale which I have treated similarly for a long time but we are not especially fond of kale so I culled most of it so as not to overly influence the other patch, assuming of course they will even cross. The kale with bluish and wrinkled leaves are our favorite and they are extremely winter hardy so I left a couple of them to cross in a little bit, if it does.

My goal was winter hardy greens with a cabbage like flavor that matured food outside the range of those worms and am really pleased with how it has turned out. I will probably just harvest a pint or so of the first seed and pull the plants to use use the spot for something else. From the looks of it now though if I saved them all I would have pounds of them.  

(add)  I am almost shocked at the success of this project. Where keeping mature plants alive over winter failed nearly 100% in multiple attempts, 95% of these plants, sown in late summer survived winter.  

Our coldest temp last winter was about -5 F, without snow. It can get considerably colder than that here but with this big stock of seed I'm confident I can develop my new worm proof, drought proof cabbage like  vegetable. I can enjoy bountiful harvests, weeks even months before the time I used to plant this species.

It was really hard for me to try to overwinter mature turnips. If I plant them in late summer, they overwinter splendidly, in the garden, as golf ball sized roots.

I am LOVING all of the free information flowing here! Seriously, you guys are so generous with sharing tips and hard-won experience, it's unbelievable really what a great community we have here on Permies.

Sounds like late summer/early fall plantings are the way to go if one wants their brassicas to bolt in time to make seed the next summer. Also, given various posts by various people in this thread and others, it sounds like cross-pollination isn't nearly as awful of a danger as we've all been led to believe.

Something that I am learning from permaculture is that food storage isn't nearly as important as proper food cultivation. In other words, it makes more sense to have a crop of turnips in the ground all winter than it does to have them slowly rotting in your pantry. Same could be said for other atypical practices like growing a second potato crop during winter, or planting a variety of root-crop species that are harvested in different seasons of the year. Someone told me recently about an island near here that is still inhabited by indigenous peoples who have created their own climate and landraces, and even the fruit trees bear year-round. How's that for a solution to food storage! I think once travel restrictions open up here I'll try for a trip and bring back lots of photos.

In short, thanks everybody for the sharing of information. I still refuse to grow kale! But I'll share progress on my brassica-breeding adventures and maybe we'll come up with a sweet, crunchy, winter-hardy 50-lb cabbage landrace. Yum!

Lacking a root cellar and having very limited space, alternative methods of having food available is important to me so finding or developing things that can just be left be in the garden and harvested as needed is a goal.

Along with that I tend to favor things that can be stored easily without processing or refrigeration. Dry beans and corn for example. Sweet potatoes are an important crop for me as they store for a very long time just at room temperature and can be grown for greens in a south window all winter.

When I first decided to become independent in my seed saving I got a book called "Seed to Seed" by Suzann Ashworth. She is affiliated with the Seed Savers Exchange and her book is focused on saving seeds of pure varieties and includes all the info on isolation distances to insure purity and population sizes to prevent inbreeding. I was very discouraged because I didn't have the space to accomplish either of those things.

Then I realized I didn't care about "pure" varieties. A vegetable is a species not a variety, I don't care if my oxheart carrot crosses with my other carrots. The result is still a carrot. The issues of isolation distances and population sizes are irrelevant, crossing of varied individuals eliminates genetic depression for generations to come.

Now I love her book, it has all kinds of great information on what crosses with what, how to process and save the seeds and so on. I just use that information a little differently than it was intended.

There is a new book now called "Landrace Gardening" by Joseph Lofthouse. I haven't read it yet but am pretty familiar with it's concept and plan to add it to my library. I suspect that those two books will complement each other in a way that is extremely valuable to someone such as me. That is someone interested in self sufficient gardening but not overly concerned with learning all the specific technical detail of genetics and so on.

As far as my winter hardy cabbage(ish) vegetable goes, now that I have my first good crop of seed I will plant a bigger patch this fall. Winter will do the first selection, showing me which ones are most hardy. Next year by favoring them in seed saving I will begin selecting for those that make the most and largest of the tender stalks and flower clusters. All the other traits will be left to do as they will. My new vegetable will never look the same one year as the next or even all the same in the same year but it will be adapted to my garden and it will never suffer from genetic depression.

For me Brassica oleracea isn't cabbage and broccoli and kale. It's Brassica oleracea. It isn't even biannual, it's just that it's annual cycle runs from summer to summer and the winter period it needs to produce seed just conveniently occurs in the middle of that cycle.  

 

This PDF is really good for clearing up the likelyhood of crossing between Brassica genusses.
It contains percentages of succeeded crosses per genus by handpolinating with the most likely candidates.

https://www.agronomysociety.org.nz/files/2002_9._Review_-_Brassica_cross-pollination.pdf

I love all this conversation. I want to save cabbage seed but live in zone 4. Can I plant in fall and harvest seeds in fall. Or should I do summer to summer planting for seeds.

Cabbage grows as a biennial. Therefore, plant this summer for seed production next summer. Late summer to early fall plantings tend to work well, and may prove easier to overwinter than early spring cabbages.

Mae Hein wrote:I love all this conversation. I want to save cabbage seed but live in zone 4. Can I plant in fall and harvest seeds in fall. Or should I do summer to summer planting for seeds.

Joseph Lofthouse wrote:Cabbage grows as a biennial. Therefore, plant this summer for seed production next summer. Late summer to early fall plantings tend to work well, and may prove easier to overwinter than early spring cabbages.

Joseph,       Our being in zone 4 also has me wondering -- is it really possible to overwinter cabbage here even with heavy mulching?  Wouldn't one need to pull a few cabbages in the fall....roots and all....for winter storage in the root cellar and replanting in the spring for seed production?  This past one was the first winter since we've been here that Swiss chard seed in the garden survived and gave rise to many volunteers.  A friend is quite interested in some of these plants for examining for cold hardiness since, even though it was a mild winter by our standards, it may have provided pretty strong selection for cold survival.  The seed came from plants that bolted in the first year so skipping the normal biennielism.