Saturday, 24 February 2018

Results from 2017 and a sweet potato hiatus

I've been getting some requests to write down the results of my 2017 sweet potato grow-out, so I decided to share the below harvest table (yields in kgs) I made back in October. The numbered plants indicate sweet potato seedlings, mostly from my own seed, which is primarily a cross between Bonita and Purple. There is also some traded seed in there, though that generally did less well than my own. Though the difference in yield between individual plants of the same variety can be substantial (hence the table is somewhat biased against varieties of which I grew more than one), it's quite clear that some of these seedlings are performing at least as well as their parents. S17-022 stands out so much that I'm wondering if I made a mistake somewhere (though I really doubt it), so I'll need to confirm its potential in future seasons.

All plants were grown outdoors, without plastic mulching, and with the application of a floating row cover until the first day of flowering.

I also harvested much more seed than I did last year, probably more than 300-400, I didn't really count, but plenty to work with.

You'll notice that things have been a bit quiet around here lately, which has to do with some accumulating research obligations in my non-sweet potato life (it does exist!). I'm currently away from my garden for a year due to a visiting research stay abroad, which means my sweet potato breeding work is on hold until 2019. I've however shared my material with a number of other growers and hopefully I'll be able to report on their results in Fall. I'm eager to continue working with this material after that, it feels like we're making some early but promising progress on developing more cold-tolerant sweet potato varieties. I'll be back!

Saturday, 12 August 2017

Sweet potato breeding project - generation 1

First to flower and first to set seed -
seedling from a purple-leaved variety.
Let's talk batatas! Last year I managed to get some of my sweet potatoes to flower and produce seed, a first step towards breeding new, and in the long-run hopefully more cold-adapted sweet potato varieties. Since true sweet potato seed is a bit of rarity (at least in these parts of the world) and plant breeding significantly benefits from collective efforts (and since my own gardening successes tend to be somewhat erratic), I figured it would be wise to spread the responsibility a bit and so I distributed about half of my seed to other growers. I also received some seed back in trade, so that in total I had seed from 4-6 parent varieties. All of these were sown sometime in the beginning of April (if I remember correctly). Germination rate was high (it helps if you scarify the seed first), probably around 90%, and I ended up with some 50-ish seedlings of varying leaf types and growth habits. These duly went into the garden in the second half of May, a bit earlier than the varieties I'm propagating from slips. I took cuttings from most of the seedlings so that I would have at least two plants of each new variety, just as an insurance policy against unforeseen circumstances - think inadvertent gross neglect or sudden rodent mayhem.

Flower bud abundance
I cover all my sweet potatoes with a floating row cover until they start flowering, which happened surprisingly early for the seedlings. The first flower buds appeared at the end of June, when most of the plants were still fairly small, and by the end of July some of these seedlings were flowering prolifically. I'm not sure if this has something to do with the fact that seedlings were raised indoors, and that they were therefore subject to a fairly large change in temperature when they were planted out (though to some extent so were the slips, and they didn't respond in the same way), but it's something I plan to investigate further. Most of the plants that are flowering are putting out an abundance of buds, not unlike the variety Purple, which is likely to be one of the parents. In fact, all of my own seed is probably a cross between Purple and Bonita. I noted four flowering varieties last year, but I've since become convinced that the variety I named 'Nordic White' is actually Bonita, while Georgia Jet really only produced a handful of flowers at most, and even then late in the season.

Except for some hesitant hoverflies, the bees and bumblebees didn't seem all that interested in the flowers at first. I suppose that's what I get for seducing them, right next to the sweet potatoes, with a generous patch of lacy phacelia (Phacelia tanacetifolia), which is a veritable bumblebee-magnet. For a while I also didn't see any evidence of seed formation, but something has been busy with those flowers, because after returning from a trip abroad and rushing out to the garden today I found some seed pods on the plants that were flowering first (top picture). Bless you, loyal mysterious pollinator. To be fair, now that the phacelia is done flowering I've seen a number of white-tailed and red-tailed bumblebees on the sweet potato flowers. Together with the fact that the diversity of I. batatas genetic material in my garden this season is a lot higher than last year, I'm hopeful I'll get a good amount of seed by the end of the season. Since we're having a fairly average summer so far, with plenty of rain and so far very few really warm days, that would be a significant indication that I am able to get true sweet potato seed under normal environmental conditions here in southern Sweden. A few seasons of that and I might have reliably-flowering breeding material from which to start selecting for early and temperate climate-adapted tuberization. We're not quite there yet, of course, and it seems like temperatures will be staying below 20℃ over the next two weeks. Fingers crossed!

True sweet potato seed forming

Part of the sweet potato patch - 12 August
Apart from the seedlings, I'm also again growing the best from last year's varieties - Bonita, T65, Nordic Orange, Georgia Jet, Purple, as well as one of my Papua New Guinea seedlings from last year (Papua White-16), an old heirloom called Patriot, and two improved American varieties called Orleans and Bellevue that I received through the people at SLU Alnarp (the Swedish Agricultural University, who are currently also doing tests with growing sweet potato in southern Sweden). As last year, I noticed flower buds appearing on some of these plants by the end of July, and today I saw that Bonita has started flowering. Overall, I would say that things are going pretty well for the sweet potatoes. I lost three seedlings, probably to the voles, but that's it so far. To be continued!

Saturday, 26 November 2016

Seed!, Seed!, Seed!, Or: A bright beginning to batata breeding (for beginners)

So. Things have been a bit mad around here for the last few months, what with defending a dissertation and all, which means a lot of things became hopelessly delayed, including harvesting things, and writing blog updates about harvesting things. I'm slowly getting there though, even though I will abstain from making promises of more regular future updates. It is what it is, my tiny cohort of somewhat-loyal followers!

The sweet potato plot in late August - with bagged pods
First up, this year's great I. batatas success. Damnit.. now I already gave it away. To recap, I had 13 different sweet potato varieties at the start of this growing season. Burgundy never made it out of the house, so only 12 of them ended up happily populating the batata plot, together with some 20 seedlings derived from seed originating in the Papua New Guinean highlands (don't ask...). Of these 12, the two Papuan tubers I had (unsurprisingly) proved somewhat too exotic for these latitudes (the fact that they were late to produce slips probably didn't help) and didn't yield any offspring that I could keep for next year. This left me with 10 varieties that all considering did rather well I think. The table below gives the yields, and my rough attempt to evaluate how much space I allocated to each variety, in order to give an estimate of the relative yields. I should underline that the space allocations are estimates that probably have a significant error margin, since, well, I completely failed to measure them properly prior to harvesting. Still, it should give a general idea of what varieties did best this year. At least the general direction of these numbers corresponds to my (very unbiased, naturally) subjective impressions of the harvest.

Sweet potato harvest table - 2016

As you can see, the most productive variety in my garden this year was not T65 (surprisingly, given its reputation as one of the most cool climate-tolerant, and given its indisputed domination in previous years), but Nordic White, followed by an unnamed variety originating from Telsing (and that might, in fact, be T65 - you didn't think this was going to be easy or straightforward, did you?). Georgia Jet and its clone, Mystery - those sweet potato superstars of the temperate Americas - again failed to live up to its promises here in Sweden. I suspect that even though GJ is a short-season variety, it requires fairly high temperatures to produce decent-sized tubers, and we certainly have cooler summers here than in much of the northern US and southern Canada. That being said, this was in many ways a dream year (in relative Swedish terms) for sweet potatoes here, with a very warm spring followed by a fairly decent summer, followed again by an unseasonally warm September. I've added a temperature analysis below: overall this growing season was about 1.2°C warmer than the same period in 2015. As for a bit more details on my cultivation practices, all of the listed varieties were grown outside, on ridges, without ground cover. Plants were covered with row covers for the first half of the season, until around the end of July, when the first flower buds appeared.

This is most of the harvest except for Bonita, Nordic White and Nordic Purple

As expected, the PNG seedlings didn't produce all that much. Nevertheless, it was an interesting little experiment. There was large variety in terms of growth habbit, leaf shape and colour, tuber morphology and skin and flesh colour among the seedlings. White, cream, purple-ish and various shades of copper-coloured roots were all present. One plant yielded three medium-sized white tubers, which I will attempt to keep for next year. The rest will be discarded. All of this gives me little reason for sorrow because, my friends, I now also have more promising seeds to play with! The (F) behind Georgia Jet, Bonita, Nordic White and (Nordic) Purple indicates that these varieties flowered and set seed this year, which, as the internet might have told you, is somewhat of an anomaly in batataland. Georgia Jet produced only one pod (I believe), but might have contributed pollen to the others. Bonita and Nordic White were earliest  to flower and put out quite a lot of pods in the end, though the absolute flowering and seed-producing champion was Purple, which flowered some two weeks later but when it did made the others pale in comparison. I should note that Bonita and Nordic White, which I obtained from different sources, appear very similar and I'm not entirely sure anymore that they are in fact distinct varieties. For the time being, however, I will treat them as such. None of the seeds fully matured on the plants before I needed to harvest the tubers in the first week of October, so I cut off all of the stems with pods on them and put them in water indoors, until they had fully dried. I've tallied up the totals last week, and in total I now have 104 sweet potato seeds to play with next season. Excuse me while I make a little victory dance. I also got my hands on seed from three other varieties, produced by a fellow batata enthusiast in the US, so there should be a bit of diversity here to start working from. Now it's just a matter of upscaling seed production and growing out tens of thousands of seedlings in order to start selecting for adaptation to northern Europe. Easy! Maybe someone wants to contribute with some land and some long-term research funding?

Sweet potato seed pod
Malmö weather - 2016
2016 compared to 2015: avg temp between June and October 2016 was about 1.2°C higher than 2015

Tuesday, 4 October 2016

A leguminous verdict

Wolverines's orca bean
Summer's over, though it took a while before I could say that with some confidence this year. 26 degrees Celsius in the middle of September is certainly out of the ordinary for this part of the world... If it wouldn't be an indication of a rather ominous trend, I wouldn't have minded so much. As it stands, I can't help but think that I'd rather have my sweet potatoes adapt to the Scanian climate than the other way around.

 In any case, it's time for some harvest updates. I'll start with the legumes, since these are all in, fully dried, shelled, sorted and weighed. As you might remember, I had a few different legumes on the trial table this year: favas beans, peas, beans, lentils, chickpeas and some lupines. As in any good story, this turned out to be a tale of heroic successes (well, kind of), epic failures, and everything in between.

Chickpea pods
Chickpea flower
If we start with the epic failures: I've discovered that something or someone inhabiting my allotment likes chickpeas at least as much as I do. My chickpea plants did fabulous in the beginning. They germinated without much of a problem in fairly cold soil, happily grew on during the warm spring, and were soon filled with cute-looking pods. Quite a few of these pods appeared to be empty, which I had read could be due to bad pollination (in turn due to low temperatures perhaps), but a lot of them seemed to have good-sized chickpeas in them. But then the disappearances started occuring. Somehow a lot of the pods just vanished before they fully matured. I didn't make much of it at first, as I've learned to accept that the various non-humans I share the garden with demand some form of tribute from me, but when the empty pods started piling up between the plants I realized I was dealing with more than your average chickpea thief. Soon I had no pods left. I'm absolutely clueless as to who or what the culprit is. I covered the plants with netting for a while with the idea that the finches might be to blame, but the chickpeas kept disappearing. Since even the pods at the top of the plants were stolen, it feels like it can't have been a mouse or vole either. Whoever it was ate a decent-sized hole in the pods, ate both the immature and the nearly-mature seeds, and then left the empty pods in provocative-looking little piles at the foot of the plants, as well as in the adjacent pea row... Any help with identifying the rascal responsible for this greedy injustice would be much appreciated! The result of all this is that the entire chickpea harvest this year consists of half a handful of tiny seeds. Not exactly hummus material, sadly. But don't you think that I'm giving up yet!

Chickpea massacre
This year's lentil story unfolded in rather similar ways. One way or another, the lentils pods developed and then just vanished in thin air. I didn't even bother looking for survivors, since I had already decided that lentils are a bit too finicky to work with anyway. I dug them all into the soil, may the lentil project rest in peace.

The fava beans did well and I enjoyed a decent amount of them fresh. I left plenty on the plants to dry as well, though here too I had to sacrifice some to the local fauna. The bigger problem manifested itself when I starting shelling the dried beans. The majority of the pods had been invaded by what I surmise is the broad bean weevil (Bruchus rufimanus), whose larvae eat their way into the bean and then emerge from the dried seed as an adult (and rather confused-looking) beetle. The result in my case was a majority of seed with beetles or beetle-sized holes in them... While probably still edible, they're a bit of pain to sort and clean that way. I'll probably stick to eating my fava beans fresh.

On to happier news then. Dried peas are susceptible to weevils as well (Bruchus pisorum to be precise), but luckily this species is a bit less common in these regions (for the moment) and I haven't had any problems with it in my garden the past year. The different pea varieties did very well, even though the cursed pigeons decimated everything that grew out above the trellis that I had constructed. Luckily, since the trellis was pretty high anyway, the damage was fairly limited. Some of the peas had larvae of the pea moth in them (Cydia nigricana, - one certainly learns a lot about insects and their insecty habbits as a gardener), basically a small white larva that eats its way through some of the peas and then leaves a trail of web and excrement behind. Thank you very much! Overall it wasn't too bad, I think I eventually had to throw out between 5 and 10% of the peas. What was left was the following, in brackets is the approximate (and I want to underline approximate) space I had for each variety:

- Govorov - 45g (I only had a few plants of this)
- Klosterärt - 600g (a 2 meter row)
- Biskopens gråärt - 340g (1-1.5 meter row)
- Bjurholms småärt - 840g (2 meter row)
- Gotländs blåärt - 710g (1.5-2 meter row)
- Solleröns gråärt - 300g (1 meter row)

Biskopens gråärt
Bjurholms småärt
Gotländsk blåärt

That's a total 1790g seeds for some 8 meters of peas, or a space of 3 to 4 m2. I'm pretty happy with that, and I look forward to the taste test.

And then, of course, for the beans. Not many problems to report here, the beans were pretty much pest-free and due to a dry and warm late August and September they dried well on the plants. The results, again with an estimate of the growing space for each variety in brackets:

- Huttiternas soup bean: 280g (1.5m)
- Borlotti: 1500g (6.5m)
- Brightstone: 910g (2.5-3m)
- Stella/Bruna bönor: 760g (3.5m - these were supposed to be 2 distinct varieties but they are almost identical and ended up together.. woops)
- Wolverine's orca: 310g (2m)

Stella/Brown bean

Summed up, that's a grand total of 3760g of dried beans for 4 rows of 4 meters, or about 6 to 8 m2.

Lupin bean (L. albus)
The lupine, finally, is still out there braving the current autumn spell we're having. I only have a couple of plants and my objective is just to see if the seed is at all edible. No big expectations there.

The final verdict of The Great Legume Project? I'll be growing more peas and beans next year, drop the lentils and stick with fava beans as a summer crop. I'm definitely trying chickpeas again, against all ods, simply because I'm biased towards chickpeas, but I'll probably be guarding them closely. Think the batata garden, annex chickpea fortress.. something along those lines. 

Saturday, 30 July 2016

Mixing up the maximas

You might remember that I threw all cucurbit seed-saving advice in the wind this year in embarking on something of a C. maxima landrace adventure. I've let the bees do their pollen dance and then saved and planted whatever crosses they've come up with. Since I garden in an allotment, and some of my neighbours grow winter squash as well, there's bound to be some cross-pollination with varieties that I've not selected myself. As I'm fairly picky about my winter squash, I should confess that this instilled some doubt in me at first. If I've understood the science behind this correctly, however, cucurbits are mostly pollinated by themselves or by neighbouring plants, so most of the genetic material should in fact come from within my own winter squash patch. And anyway, it's fun to try and mess things up a bit to see what happens.

 The squash are starting to mature now, which makes this an appropriate time for a first evaluation of what the bees have been up to last year. My main selection criteria, of course, will be taste, but based on growth habbit and appearance I think I can already draw some preliminary conclusions. Without further ado, here's this year's winter squashes. Let's start with the crosses:

Both of the above are a cross of Sweet Mama (F1) and an unknown paternal line. Because of the salmon-coloured spots on the squash on the left I would speculate that there's some Galeux d'Eysines genes involved (which is a pity since I didn't think it was very good, but that's the name of the game of course). Since it's a fairly round squash however, which is unlike either Sweet Mama or Galeux d'Eysines, there might be something else going on here as well. The squash on the right looks like it might be cross with Sweet Meat (because of the colour) and/or Marina di Chioggia (because of the pronounced ribbed structure).

This is another Sweet Mama (F1) cross. I'm not sure if you can tell from the picture but this is one big squash, at least half a meter in diameter. This poses a bit of a mystery since I didn't grow anything this big last year. The only variety that comes close is Galeux d'Eysines, which can, apparently, get quite large. Now genetics isn't quite as straightforward as that; you could very well cross two medium squashes and up with a larger one, but still, there's a likelihood that this is actually a cross with something from one of my neighbours. It's also definitely more yellow/orange than the Galeux d'Eysines I grew last year, though apparently there's a bit of colour variation in the latter as well. The stripes are probably from Sweet Mama (it shows up in quite a few of the crosses, could be a dominant allele?). I'm selecting for small to medium-sized squash, and I've yet to come across an orange-skinned squash that rivals the green or blue ones in taste, so it's unlikely I'll be saving seed from this monster. It looks impressive though.

This Burgess Buttercup cross more clearly includes some Galeux d'Eysines genes. It has the stripes and shape of Burgess Buttercup, and the skin colour, size and some of the warts of Galeux d'Eysines. I hope it inherited its eating quality from its mother...

More Sweet Mama offspring. This squash has a slight teardrop-shape, which makes me suspect that it might have crossed with a hubbard squash. I only grew Blue Ballet last year, which is a scaled-down hubbard, and this is one is quite a bit larger than that, but still, that would be my best guess.

Then there's also some less exciting crosses:

This looks pretty much like a Sweet Mama squash, but it's more vining in its growth habbit and perhaps a bit more squared than your average Sweet Mama, so it might actually have crossed with Burgess Buttercup. 

A Burgess Buttercup cross that looks exactly like a Burgess Buttercup, if perhaps slightly less block-ish. It probably crossed with itself.

This is a Green Hokkaido cross. Again, I fail to see the difference with the original Green Hokkaido at this point.

Finally, I'm also growing a bunch of named varieties this year, mostly to add some more (supposedly) excellent squashes to the maxima mix, and also simply because I seem to have an unquenchable thirst for trying new winter squash varieties. I've only got one plant of each of these:

To the left is Sibley, to the right Guatemalan Blue. Both are banana-type squashes with supposedly excellent eating quality. Guatemalan Blue is significantly larger than Sibley (it's probably about 40-50 cm long), but not nearly as productive (I've counted 4 medium-sized Sibley squash on the one vine that I have, which is quite good for a Maxima squash, at least in my garden)


Ah, Marina di Chioggia (left), one of my absolute favourite maximas so far (taste-wise) but frustratingly late to set fruit and mature. I can't give it up though, so I'm hoping to transfer some of its genes into my proto-landrace. To the right is Bon Bon (F1), a Buttercup-type that I'm quite impressed with so far. I'm not sure if it just happened to get the best and most fertile spot in the garden, or if this is really just a superior variety, but this is one healthy-looking and vigorous plant. If I'm not mistaken I've counted 7 decent-sized fruits on this one vine, which would make it by far the most productive maxima I've grown so far.

Hokkaido, from Real Seeds. This seems like a pretty standard orange Kabocha squash, though it was probably one of the earliest to vine and set fruit. The leaves on this plant have a silvery appearance to them, which is a bit unusual.

Sweet Meat Oregon Homestead or Blue Kuri. I'm growing both, and they seem similar enough for me to have forgotten taking a picture of the other squash. At least Sweet Meat, whichever of the two it turns out to be, seems to be doing much better than last year, so hopefully I'll have the opportunity to evaluate the fully-matured squash this time.    

Crown Prince, a squash with a royal reputation.

Blue de Hongrie. Not so much Blue as white though...

Buen Gusto de Horno. I'm not terribly impressed with this one so far, though I had read a lot of good things about it. This plant isn't particularly vigorous and it has only put out one fairly small squash. The taste better be out of this world!


And last, and perhaps also least, Uchiki Kuri, which put out two tiny squash and then decided to just sit there and enjoy the sun. I'm not sure things will work out between us. 

So far so good, perhaps I've inherited a bit more Galeux d'Eysines genetic material than I had bargained for, but all in all there's some interesting material here to work with. Needless to say I already look forward to the taste testing. I've also become intrigued with the genetics involved in all of this, so next season I'll probably try to make some controlled crosses just to play around a bit. Sweet Mama x Marina di Chioggia seems like an obvious choice; I was already planning on doing that this year but I didn't get around to it.

The winter squash patch, with some reluctant watermelons in front.
The dark green plant in the front row is Bon Bon.