Sugar beet X yellow and red chard

[Steph S]

A couple of years ago my friend discovered that sugar beet greens were sweet and tender - the answer to bitter chard and beet greens.   I've been growing them for greens ever since, and last year I had overwintered sugar beet and red and yellow chard, which I put outdoors together to flower in hopes they would cross.  Since I read that colors are dominant to white in the beet family, I sowed the seed from the sugar beet plant this spring, to see if I could find any colors.  They are just big enough to see colors in the stalks, and indeed there are plenty of red and yellow ones so they crossed quite a bit.

Would I be right to assume that these F1s are all basically identical?   Or is there much heterozygosity in beets and chard?

If they are identical, I'm thinking to keep three plants each of the yellow and the red to overwinter for F2 seed next year, then select for good tasting plants with some color and the bigger stalks.

[Steph S]

This article, if I read correctly, suggests around 20% heterozygosity.
Genetic diversity among cultivated beets (Beta vulgaris) assessed via population-based whole genome sequences
doi: 10.1186/s12864-020-6451-1
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7053042/
So I will give all the crossed seedlings equal chance and select which ones to overwinter in the greenhouse for seeds.
It's too bad I can't do that in ground outdoors, but every stray root crop got gnawed into the ground last winter, including those outdoors in pots.  Nothing left to sprout from.

[Steph S]

So I planted out these F1 seedlings to see if anything stood out besides color, and they didn't grow too big or get any attention, until a few nights ago a mother moose and two calves came by and very attentively mowed the lot.   They were pretty gentle about it only the calf pulled a couple out - sugar beet in another bed the roots were yanked and strewn.  They're fond of the tops but left the roots.
I went out today to pick out a few plants to pot up for seed in the spring, and I discovered that the moose had been selective.  Some plants were not touched at all.  Since moose have a very keen sense of smell, I wondered if they preferred the better tasting ones.   I took up most of them and the plants they didn't touch got moved to a bed where they can overwinter if they turn out to be "moose resistant".  The visible trend was that the moose rejected plants with more slender roots.   A number of the rejected plants turned out to have a very long deep tap root, while the preferred plants had rounded top roots.  Those moose-selected plants came into the greenhouse to regrow.

[Diane Whitehead]

We're able to fence deer out of our vegetable gardens here. Wire fence a bit taller than me does it since I have a lot of trees and they can't get a good run at my fence to go up and over it. 

I guess it would take a big strong fence to keep moose out.

[Steph S]

It wouldn't be possible to fence the entire area, and for sure you'd need a minimum 6 ft fence to exclude them.  But minor barriers to vegetable beds have worked well with rabbits and even moose.  They are deterred by flapping row cover afaict, and less interested in shorter crops generally.   A simple rail which they can see (poor eyesight there) keeps moose from trampling the beds when planted in garlic, and row cover is very visible and in past experience they generally avoid it.   I did have row cover around that bed but removed it before hurricane Larry, and so doing I guess I signalled to them that they could freely glean. 
Until this year the moose visits have pretty much been limited to autumn gleaning, which I don't begrudge them.  The missus mooses come with their young calves, eat the evening primroses and/or the black currant bushes, and introduce the little ones to a variety of other herbs and shrubs, and the occasional vegetable such as late peas on trellis, or previously enjoyed brassicas, if the row cover is gone.  They do seem fond of sugar beet as well.  But there are things I can grow that they won't bother, garlic obviously, and I'm learning what else does or doesn't appeal.  Mustard and oats and wheats weren't bothered by the lurking yearling moose this summer, but barley was distinctly a favorite along with the peas.

Relationship with moose is subject to continuous evaluation, but regarding the tall peas I really got the trouble I expected.  Experiment confirms hypothesis ha!  Not sure where I will go with that in future but shorter peas and earlier peas are a definite must, and those I can more easily protect.

[Steph S]

Things have heated up early in the greenhouse, and a surprising amount of growth on those overwintering sugarbeet-chard F1s.
I potted up only the ones that I could see are differently colored, so as to have a more or less even number of different colors.
There were only two red ones, and they are two different shades.   And there were quite a few which have pink at the base of the stem but not much higher.  So it appears there are several genes involved in the red shades.   I also suspect that some of the yellow ones have the 'pink base' gene as well, because they have a much more intense color at the base of the stalk.
I had a lot of extra plants in the pink and yellow groups, which also got rescued and are alive but just heeled in not potted up.
I may go through them carefully and see if there's anything distinctive that I should include.
Otherwise, it seems that the seven F1 plants I have representing the full range of colors are enough to produce plenty of F2 seeds.
I'm thinking to allow them to cross freely again amongst colors, rather than separating them from one another.
IDK if anyone has any advice about that but any comment or suggestion would be welcomed.   

[bill]

Beet color genetics are pretty straightforward.  It is a two gene system: R (red) and Y (yellow).

R-Y- gives red.
rr-Y- gives yellow.
--yy gives white.

Another way to look at it is that Y is the master color gene.  A dominant Y gives you the possibility for yellow or red, while homozygous y gives no color.  I don't know anything about the specifics of sugar beet or chard genetics, but assuming that they do not have additional genes involved, the sugar beets should all be --yy.  They might well have dominant red alleles that are not expressed, which opens up the possibility that reds will outnumber yellows in the F1.  My guess is that, since chard has been selected for intense stem color, the yellow chards are probably rrYY and the red chards are probably RRYY or RRYy. 

If those assumptions are correct, then your more intense reds are probably RRYy, while the pinks are RrYy, with lower dosage of the color alleles giving less intense color.  There are probably other, lesser, probably quantitative genes involved since there almost always are.  Your yellows would all be rrYy.  You probably don't have any --YY plants because they have all inherited a recessive y from the sugar beets.  In that case, the goal would be to cull everything that lacks intense color because you want to get rid of as many contributors of the recessive y as possible.  You might also want to separate the reds from the yellows, since your population will favor reds in the event that the sugar beets carried a red allele.

I am curious to learn about your taste testing results.  My guess would be that the leaves of the colored varieties will taste more like chard, because it is the betalain pigments that are producing much of the flavor.  If they are non-bitter like sugar beet greens, that points the finger elsewhere.  Are non-colored chards as bitter as the colored varieties?

[Steph S]

Thank you Bill.
I suspect that it is the oxalate content that contributes bitterness to the 'earthy' betalain flavors. 
I've always noticed that the green leafy part of chard is more bitter than the stems.  Also I find common beet greens to be even worse.
I did a little search this morning and was not able to find anything on the oxalate content of sugar beet leaves perhaps because they're not usually eaten.
But what I did find tends to support the probability that oxalate content is the more bitter and unpalatable component.

This article confirms variation in oxalate content among beet and swiss chard cultivars, sufficient that it could be the subject of selection.
https://journals.ashs.org/jashs/view/journals/jashs/136/1/article-p54.xml
They identified Fordhook Giant - a white swiss chard cultivar - as having the lowest oxalate in their tests.   I haven't noticed a big taste difference in white vs colors of other Swiss Chard varieties, but I can't say I'm an expert or gourmand of any of them tbh.  I
I also browsed a couple of studies on preparation methods which reduced oxalate to some extent.  A study in NZ gave figures for stem vs leaf of chard, and confirmed that the stems are significantly lower in oxalate compared to the greens.   Since the stems are the most highly colored part, that suggests to me that the betalains themselves are not bitter.
One article looked at bioavailability of oxalate from sugar beet roots compared to spinach, and found the SB roots bioavailable oxalate to be really quite low, although the reason was not determined.  One suggestion was that high content of calcium and magnesium may have played a role in, I guess, binding the oxalate.
https://pubmed.ncbi.nlm.nih.gov/2731814/
So at this point it's not clear to me why the sugar beet leaves are less bitter than their cousins.   
I did read earlier that the sugar beet has been through a severe genetic bottleneck compared to other members of the Beta family.
It is possible that in the process of selecting for high sugar in the root, they also selected away from the higher oxalate content unintentionally?  Or intentionally - I've not found any work confirming that though, at this point.  Or perhaps it is present but less bioavailable due to Ca Mg contents?  All guesses.

I found an article that identified oxalate as the unpleasant taste in spinach:
https://www.researchgate.net/publication/316808535_Is_Oxalate_Responsible_for_the_Unpleasant_Taste_of_Spinach_Leaves

Another possibility is the bitter saponins which are common in the Chenopodiaceae.
https://www.researchgate.net/publication/303888730_Triterpene_saponins_as_bitter_components_of_beetroot
https://www.researchgate.net/figure/Relationship-between-sweet-and-bitter-taste-of-skins-A-and-flesh-B-of-evaluated-red_fig2_303888730

[Richard Watson]

Interesting project Steph. Ive got Mangle beet in my collection as well as Fordhook Giant, think I might make that a project for next growing season, cant at the moment as I have a beetroot grex crop in the ground atm.

[Steph S]

I don't think I've ever tried the Fordhook but it sounds like a good candidate for sure.
It was really helpful to think about 'what makes beet greens bitter' this morning.
I wasn't even aware that saponins were also present, and hadn't thought about the oxalate.  Being sugar beet, it made sense for the leaves to be 'sweeter'. 
It also makes perfect sense that when sugar beet was selected (1700's) they selected away from anything bitter, so maybe lower in both for that reason.

The research from NZ was using yoghurt to neutralize the bioavailability of oxalate.  Calcium binds it, less risk of adverse health effects.

It might be helpful for selection purposes to have a simple screening test for oxalate and saponins.  They are both water soluble.
Also they say that there's less oxalate in the young leaves - regrowth leaves have more.  Which could make it more difficult to screen a lot of plants at the smallest stage, because they all have less.   Assuming I get lots of F2 seeds, maybe my farmer friend would use them for the yearly crop, why not.  She grows one of the rainbow colored types - this means all those combos of Rr and Yy in different shades. 

I'm not a huge fan of Swiss Chard - eventually settled on quick pickle as the easiest and most pleasant way to use it.
But in conversation with gardeners around the world, it seems that the chard may be the ultimate survival food.  It tolerates virtually all conditions including cold and heat.  You plant it once and it continues to produce a crop all season.  Right to the 'bitter end'. 
Actually the sugar beet is probably just as hardy and as dogged a producer of greens.   Not much of a stalk though.
The sugar beet leaves were delicious just thrown wet into the pot and wilted over a drop of sesame oil. 

[Greenie DeS]

I've found "perpetual spinach" to be the least bitter chard, but I'm not especially sensitive to chard bitters. It also has less of a stalk and more leaf than most chard.

Did you ever taste the difference between the moose-favoured and moose-rejected chards?

[Steph S]

The moose rejects are planted outdoors - they've died back completely but may yet sprout if they survive.  Part B of the critter test is that no hungry animal chews them back in the spring.  I suspect hares or maybe squirrel were the ones who gnawed the tops right off the roots when I left some sugar beet out in containers.  I didn't taste these (yet) and did no comparative taste test on any of them last year other than munching a few.
So today I decided to taste the potted up F1s and compare.  They are into their second year now and overall bitterness is pretty bad.  Considering I don't usually eat them raw, I definitely would not eat these raw.      But I tasted them, stem and leaf tip.   I do think there are two types of bitter, with the oxalate having more of a puckering effect at its worst. Laid out by order of most to least bitter in the pic.     One of the yellows was the mildest by far, both stem and leaf tip, while the other was quite bitter.  This surprised me because I've always found the yellow to be mildest of the lot, but my impression now is that there's a fair bit of variation from plant to plant.   The fully red RR stem tasted just like a beet.  Call it "earthy" and very strongly so but not bitter.  Milder but similar on the RrYy? stem.  But the RR red had a lot of oxalate pucker in the leaf tip taste.
I was also surprised that both of the pink-white stemmed are strongly bitter.  To be fair, the leaf is a mild pleasant green with a stunning unpleasantly bitter finish.
Since I do have a lot of extras in the pink-white and yellows, I'm now thinking I should taste all of them and see if I can find any milder ones that I should include in the seed production.    Shame the moose isn't tame, I'd try and talk Rosebud into doing the job for me.
 

[Steph S]

Updating this project, since I've just started a flat of 72 F2 seedlings to do a color check and hopefully some taste testing.

In the end, I didn't separate the colors to reduce the impact of R and --yy, mainly because the bolting rate of the plants was so different.  In particular, the fully red plant remained very small and produced flowers much later than the others, while the white stem with pink at the base was also quite late.  The yellows bolted much earlier than the others, followed by the pink stem, with a significant time gap before the white and red.  Seeds were collected in 3 lots, with most seed produced by the earliest yellow and the pink stem, second lot including overlap with the white stemmed, and last and smallest lot from the red and white alone.

Bolt resistance has been identified by my farmer partner as a key trait, since she tried a different chard this past season and was miffed that the red ones bolted.  So I will be keeping an eye on that, and try to avoid selecting for bolting - although none of these bolted in the first season, and certainly the red was very resistant.

A note on the parentage in this cross: the Sugar Beet is an OP which I bought from Pinetree Seeds.  The yellow chard is from Rainbow Chard, which is the usual one grown at the farm.  I took a plant home from the farm one fall and overwintered it for seeds.  The yellow chard in this cross was grown from those selfed seeds, while the red was the OP "Rhubarb Chard". 

You can see from the pic in april that the plants all look equally mature, although the dark red is slightly smaller and perhaps it just couldn't compete with the more vigorous pink.  At any rate it remained smaller and slow to flower through may and early july.

In planting the color test, I tried to select seed 'randomly', that is, to control my tendency to plant the larger seeds only and reject the smaller ones.  Not sure what effect that might have except that largest tend to be the earliest ones produced, so there might be a time factor.  I'm hoping to get a representative sample of the colors expected in each seed lot, with 36 from Lot 1, 27 from Lot 2, and 9 from Lot 3 (red/white).

[Steph S]

Seedlings are mostly up.  Some empty cells (8/9 in lot 3, 8/27 in lot 2 and 3/36 in lot1) and overall fewer reds than expected.
Lot 1, from the yellow and magenta plants has 52 seedlings:
16 white rryy
16 yellow shades rrYy or rrYY
13 red shades R-Y- or RRY-
7 pale pink (white stalk expected) these are R-yy according to:
https://naldc.nal.usda.gov/download/IND43968811/PDF
There are more yy plants than expected, probably overlap with the Ryy flowering.  So as Bill pointed out, these will want to be separated from the others after I select for non-bitter, and select out or separate white ones emerging from the colors next generation.
Red shades have been explained as a triallelic system affecting the ratio of betacyanin and betaxanthine, so magenta and 'orange-red' represent different alleles while RR vs Rr or combinations of the two R alleles makes for the variety of red shades. 
https://academic.oup.com/jhered/article-abstract/80/1/33/812526?redirectedFrom=fulltext
I'm not sure if both red alleles are represented in lot 1, and so far I have only one red in lot 2 and none in lot 3, where the orange red is expected from that F1 parent.

I found this interesting work which associated vigor and emergence with oxalate oxidase activity.
https://www.researchgate.net/publication/10682574_Cultivar-specific_seedling_vigor_and_expression_of_a_putative_oxalate_oxidase_germin-like_protein_in_sugar_beet_Beta_vulgaris_L
This left me wondering if the low vigor of the orange-red plant and its seeds is an indication of higher oxalate (from low oxalate-oxidase activity or other genetic cause) in the plant as well as the seeds.
This could be a convenient marker for selection against higher oxalate by choosing most vigorous seedlings/emergence, which is a desirable trait anyway.
Will be interested to see if any later germinating reds are more bitter.

Just noting as well that there appear to be two shades of yellow, so that looks triallelic too.

One other gleaning of interest, is that R, Y, and Stc the gene for stem color are part of a linkage group with B bolting, which determines annual vs biennial habit.
https://www.researchgate.net/publication/6871841_Genetic_study_of_a_new_color_of_the_beet_Beta_vulgaris_L
Considering it is still winter here, I may get some bolting if/when I put the seedlings out in the greenhouse early and they experience some low temperatures that could be taken for vernalization.  Hadn't thought about this last year, when they were started at a more normal time for transplant (no bolters at all).

[Steph S]

Two weeks from seed, this batch has true leaves and needs to be potted up soon to grow them big enough to evaluate the taste.  The late germinators didn't emerge, and there's a spread in vigor for sure, which is selectable.
Also, in the cold wet soil there were 5 seedlings that developed brown stem (I assume Pythium) and perished.  So in the february batch we have also selected for surviving the cold/wet and or for resistance to the unexpected rot.  Temps in the window usually 60F but into the 50's at night, which isn't that cool for a chard.

Ideally I would like to start a second batch when these get potted, and it looks like I might have time and light space to do multiple batches like this in the usual winter time frame, before tomatoes need all the lights. The plan to move our winter greens out to the greenhouse when grown large enough has worked really well, they're all surviving and plenty to eat without continually using up light space, and gives me a chance to work on these projects.