Author Topic: Canna edulis breeding  (Read 114 times)

S.Simonsen

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Canna edulis breeding
« on: 2018-10-20, 10:19:30 PM »
Hi everyone. I am the odd bod who has decided to tackle breeding Canna edulis/achira. We have an old clone called "Queensland arrowroot" that was grown extensively here in subtropical Australia as a starch crop in the early days of agriculture. When mechanisation arrived the Canna crop that required lots of more or less slave labor to process could not compete. We still have a local arrowroot biscuit but it now contains less than 1% arrowroot flour, and it is Maranta from Central America. Sad.

Anyway- I love this crop because it can grow under all sorts of marginal conditions. Once established the plant tolerates our irregular droughts well even in fairly dry locations, growing again when conditions are good. Its tubers grow across the surface of the soil, making harvesting easy and the plant tolerant of thin mountain soils. It is still grown on some scale in marginal mountain soils in south east Asia and the starch extracted and processed into noodles. You can eat whole cooked tubers but people report varying levels of inexplicable revulsion to the whole tubers despite them having a very neutral flavour. Very few pests seem interested in the tubers so I suspect there is an unidentified defence chemical in them. Normally after a few bites they give up. Whatever it is it is removed when the starch is processed out by grating the tubers in water and letting the giant starch grains sink to the bottom. The resulting starchy sludge can be washed and dried to make a high quality flour.

My breeding plan is to take the original clone and pollinate it with as many species as possible, plus a few ornamental strains with interesting traits like dwarfing. Plants are easy to hand pollinate though I have to get up early to beat the bees that strip the pollen off the flowers. I simply swipe my finger across the pollen, then transfer to the stigma on the target species, with good results. The Queensland arrowroot clone flowers through the winter when the other species have often finished flowering. I did experiments to find the correct sugar solution to germinate Canna pollen grains, then tried different pollen drying and cooling combinations but found all viability was rapidly lost, similar to banana pollen. Only keeping undried pollen in the fridge gave modest viability after a week. I solved the timing issue by cutting back the other species in autumn during the beginning of their flowering phase, causing them to shoot again and resume flowering in early winter. Hand pollination is necessary for seed set on the Queensland arrowroot clone, unlike the other species. I have found I need to wrap developing seed pods in gauze, held in place with clothespegs to protect them from mice and birds. Interestingly the other species seed pods seem be rarely bothered by these pests.

The aim is to develop a seed grown strain of canna that produces a useful amount of starch in its tubers. Tuber size isn't the main focus as a large number of small tubers could be more productive than a small number of large ones. I am also interested in selecting the strain to be compatible with small livestock (geese and goats in my case) so that weed control can be managed by the geese, and goats can periodically graze the tops (which they rather like). This will allow the crop to be grown in a mixed silvopasture system in order to give a starch product to complement the meat and dairy outputs. The grated roots still contain a significant amount of unreleased starch and could be used as animal feed as well after cooking or fermentation. Growing from seed also allows better management of canna viruses (the only significant pest or disease at this stage), and also allows the crop to be stored, transported and scaled up more rapidly than can be done using vegetative reproduction. Canna seeds are incredibly resilient, retaining viability for extended periods even under non-ideal conditions of heat and humidity. Seeds are supposedly also edible when ground up but I am yet to experiment with this.

The first successful season of hand pollination has wound down and those seeds have all been sowed, and will undergo field trials once they are large enough to transplant out. Those with good tuber quality will be intercrossed and backcrossed, and multiplied so that starch content can be evaluated (might be possible on a smaller scale by staining and microscopy?). Any future collaborators or potential connections in developing nations where this crop may be a useful complement to existing crops are very welcome at this early stage.

Raymondo

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Re: Canna edulis breeding
« Reply #1 on: 2018-10-21, 02:32:16 AM »
Sounds interesting. Iíve eaten tubers cooked on an open fire. They were okay but I wouldnít seek them out. I grew it once as poultry greens but the chickens werenít the least bit interested. Itís marginal were I live but if nothing else, produces good amounts of biomass.
Ray
Growing in slightly acidic clay loam over clay and ironstone

S.Simonsen

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Re: Canna edulis breeding
« Reply #2 on: 2018-10-21, 02:38:53 AM »
Sounds like a typical response eating them. People can't point out any reason to dislike them but find themselves not wanting to eat them again. I am the same with the whole tubers, but the extracted starch is really useful. Other than biscuits (not much of a baker anymore) you can add it to vegetable stews as a fantastic thickener, or incorporate it into desserts to make custard like dishes. I can see it being useful through the hotter months when you don't crave a lot of carbs but can use a little to give substance to vegetable and fruit based dishes. Keep in touch if you want to participate. It should be possible to select for a degree of cold hardiness and jumping in at the early stages gives you the best chance to find those genes in the mix. I should be producing new batches of seed crossing the arrowroot form with almost a dozen different species over the next years as they come into flower. I can probably send you divisions from this first generation of seedlings by the end of autumn if they divide up nicely.

bill

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Re: Canna edulis breeding
« Reply #3 on: 2018-10-22, 12:09:02 PM »
Flavor is my main problem with achira.  It is funny because, as has already been mentioned, it is hard to identify why I don't want to eat more of it.  The taste is fine, it just isn't great.  It makes me appreciate how much complexity there is to potato flavor, because it is something like a potato that has had all the non-starch flavor elements removed.  So, before I get excited about it, I need to find a way to develop better flavor.

The triploid achiras that I have do taste a little better than the starch extraction types.  Too bad they're triploid and therefore sterile.  I have it on my to-do list to try doubling them to hexaploids to see if they can be crossed that way.

S.Simonsen

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Re: Canna edulis breeding
« Reply #4 on: 2018-10-22, 02:10:51 PM »
Are your triploids original Andean crop strains? I had heard about them but never seen any detailed accounts of people who grew them for themselves. A hexaploid canna could be quite amazing. I might get some oryzalin one day and see if I can produce some polyploids as well.
I wonder if it is worth trying to breed for a better flavoured whole tuber, though I suspect that would probably go against the excellent pest resistance traits the genus naturally has. For me starch extraction is a great trait since the final product dries down readily, even in a fairly wet climate, and stores indefinitely, better than the vast majority of grains in this climate. As long as it is well washed there aren't any insects or fungi I know that can survive on pure starch with zero protein content.

bill

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Re: Canna edulis breeding
« Reply #5 on: 2018-10-25, 02:42:23 AM »
Yeah, I have six varieties purported to be Andean achiras.  Two are diploids that seed occasionally and four are either triploid or just poor seeders.

I realized this year that part of my problem with growing this plant is drought.  I usually blame cool summer temps for slow growth, but some plants that were growing near a drip line leak this year grew substantially taller.  So, I have probably been shorting them on water.  They always look perfectly healthy and happy, so it wasn't obvious that they were thirsty.

Gilbert Fritz

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Re: Canna edulis breeding
« Reply #6 on: 2018-10-27, 05:06:51 PM »
I tried growing canna edulis here, in hopes they'd overwinter with plenty of mulch alongside a stone wall. But they failed to come back. They would make an extraordinary edible ornamental.

S.Simonsen

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Re: Canna edulis breeding
« Reply #7 on: 2018-10-27, 07:03:57 PM »
I wonder if they have potential to become an annual crop in temperate climates. With your incredibly long day lengths during summer it may be possible to simply start them from seed every spring and still get a reasonable yield in the end. Stay in touch if you want some of my early high diversity seed to try going in that direction.