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The Yam Checklist: Starting a Backyard Dioscorea Germplasm Collection

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Well, I think I finally cracked. I went too deep, and now I mostly have yams on the brain. But that's okay... I'll never go hungry with a good yam collection.  ;)

Having read the 6 documents of "Tropical Yams and their Potential", as well as other sources, I've come up with a list of yams that I'm looking to collect, multiply and disseminate to other growers (these are marked with a checkmark: ✓). I've also listed a couple of other yams that are deemed edible by the literature, but that don't strongly catch my attention (also marked with a checkmark anyway: ✓), have been outright rejected (these are marked with an X), or have poorly-known qualities regarding their edibility (asterism: ⁂ ).

The Big 5 (or 8, depending on how you segregate the species): ✓
1 - D. rotundata (White Guinea Yam) + D. cayennensis (Yellow Guinea Yam)
2 - D. alata (Greater / Winged Yam) + D. purpurea (Ube / Purple Yam)
3 - D. bulbifera (Asian Air Potato) + D. latifolia (African Air Potato)
4 - D. esculenta (Lesser / Potato Yam)
5 - D. trifida (Cushcush / Mapuey Yam)

The Lesser 5:
1 - D. pentaphylla (Five-leaf Yam) - ✓
2 - D. transversa (Australian / Pencil Yam) - ✓
3 - D. nummularia (Pacific Yam) - ✓
4 - D. dumetorum (Trifoliate Yam) - ¿✓?
5 - D. hispida (Intoxicating Yam; also known as D. reticulata) - X

The Temperate 3: ✓
1 - D. polystachya (Nagaimo / Chinese Yam; also known as D. oppositifolia & D. batatas)
2 - D. japonica (Japanese Yam)
3 - D. hamiltonii (¿Nameless? I'd just call it Hamilton's Yam)

The Leftovers? (not a great name, but  don't know what else to call 'em; it doesn't mean they're of bad quality):
1 - ¿D. pseudo-tomentosa? (¿Nameless?) - ✓
2 - D. remotiflora ("Camote de Cerro" / Mexican Mountain Yam) - ✓
3 - D. dodecaneura (Ornamental Yam) - ✓
4 - D. orangeana (¿Madagascar Yam?) - ⁂
5 - D. brachybotrya ("Papa Cimarrona" / "Jaboncillo") - X
6 - D. humifusa ("Huanqui") - X
7 - D. deltoidea (¿Nameless?) - X
8 - D. rupicola (¿Elephant's Foot?) - ⁂
9 - D. altissima (Dunguey) - ⁂
10 - Rajania cordata ("Ñame Gulembo") - ¿X?

I'm currently growing D. rotundata, alata, purpurea, bulbifera, trifida, and polystachya. I have some possible sources to check out for D. esculenta, japonica, latifolia and additional strains of bulbifera. D. cayennensis eludes me, but though I'm sure it's here in Puerto Rico, it's not common nor easy to find (if anyone has some, send 'em my way).

I recently received a mystery yam in the mail from eBay, but it arrived so thoroughly dried out that I don't expect it to survive (though the vendor assures me that it should or they'd reimburse me, which I declined); nevertheless, I planted it anyway and hope against hope that I'll get something out of it. It was sold as a D. pentaphylla, but the vine photos reminded me of alata, and the bulbil photos resembled bulbifera. The vendor confirmed it was not pentaphylla, but I bought it anyway 'cause it was cheap and I felt like trying it out. At any rate, the vendor confirmed that it was fully edible, bulbils-and-all, so I considered it valuable anyway. If it survives, I hope to be able to deduce the species from the anatomy.

I have some D. hamiltonii seeds coming in the mail, as well as some true pentaphylla bulbils. When asked about the pentaphylla bulbils (as opposed to the tuber), the vendor said they don't eat them, but they never explicitly confirmed that they were toxic. I'd really like to know if they're edible, but since there are toxic pentaphylla strains out there, I'm reluctant to try them; if I could find a lab able and willing to analyze a cooked sample, I could lay that doubt to rest. The tuber was confirmed to be edible steamed.

There's another mystery yam coming in the mail, sold as D. pseudo-tomentosa. I couldn't find anything in the literature about this species being edible (or toxic), only that it's endangered. The photos of the yam may have vaguely resembled D. esculenta, but I may be reaching with that conclusion. Truth be told, I'd love for it to be genuine D. pseudo-tomentosa, to add another good species to the germplasm. Link here.

D. transversa is very high on my wish list (specifically the large-tubered bulbil-bearing strain), but no luck finding it yet. No idea where to find D. nummularia (which is said to closely resemble rotundata), but I also consider it important as a supposedly good-quality species. Interestingly, one document claimed that some nummularia cultivars were introduced to Puerto Rico; also, there seems to be some confusion in the literature whether to consider the cultivar "Wael" as a type of transversa or of nummularia.

I don't object to D. dumetorum if I can obtain it, but I'm not really looking for this one. The best strains still seem like poor quality yams and they have to be eaten quickly after harvesting or they turn hard (even after cooking) and difficult to peel (as if their strange shape didn't already make that a challenge). The worst strains are downright toxic, which leads me to its close relative... I don't even know how D. hispida made it into the original documents. I don't even care that they have in-fact been eaten before (and they're probably still eaten to this day), even the best strains are dangerously toxic and require jumping through hoops to detoxify and turn them edible, and we all know how I feel about that... Famine food. So I just mentioned it for completion's sake, but I don't consider that species edible, nor am I interested in it in the slightest.

D. remotiflora is an edible wild mexican yam that barely even has a presence in the literature. If it weren't for a single isolated YouTube video (link here) showing its harvest, I wouldn't even know this species was edible. It seems to bear some resemblance to D. polystachya, which is also referred to as "Camote de Cerro" in Mexico. As it seems to be rare and difficult to find, with few traits to explicitly recommend it, I won't go out of my way looking for it. But if someone out there has some and is willing to share, I'd be very grateful nonetheless.

D. dodecaneura doesn't seem like an especially important species, but it is listed in several sources as being edible raw or cooked with an almond-like flavor; it's also a beautiful ornamental. I'm kinda interested in it. A few links: Link 1, Link 2, Link 3

D. orangeana is Madagascar's only edible native Dioscorea, and is a recent discovery. I've yet to find an online source that knows anything about it, or if it's even conventionally edible (as opposed to a hispida-like famine food). Unless it's explicitly confirmed as conventionally edible, I'm not too interested in it (and even then, it's like remotiflora, where it's so rare I'm not sure it's worth going out of my way for it).

I saw brachybotrya, humifusa, deltoidea and rupicola on a YouTube video (link here) where a guy was trying to germinate them from seed (along with other rare supposedly edible species... like reticulata/hispida). When checked online, the Chilean brachybotrya & humifusa turned out to be toxic and bitter (¿saponins?), and probably require special preparation, so I'm not interested in either as a crop. Deltoidea from Asia was also said to be bitter but edible in PFAF, though the article (link here) urged caution, and mentioned that it's boiled with wood ashes to remove bitterness. It doesn't seem like a good prospect either, so I'm not interested. Regarding rupicola, I could barely find anything about it online, but one seed seller claims it to be edible (link here). I couldn't see the details because when I clicked the link it failed to open for me. Maybe the link will work for one of you and you can post the screenshot. At any rate, I'll be interested if it turns out to be conventionally edible, but as a desert plant I doubt it'd be particularly prolific as a crop, so I probably wouldn't go out of my way for it anyway.

Edit: Another species:
D. altissima was present in another seed sowing video. There's not much in the literature about it, but it's apparently wild harvested and occasionally home grown for its edible tubers in parts of its native range in South America; it's also present in Puerto Rico. A photo search revealed a very thorny stem and small aerial bulbils. I wouldn't grow it from anything other than seeds, for fear that it might carry the same virus as R. cordata, but since there's no details available on preparation & toxicity level (¿Conventionally edible? ¿Detoxification necessary?), I'm not too interested in trying it... Maybe a little. Info link here.

And finally, Rajania cordata, our very own Ñame Gulembo. It's a close relative of Dioscorea. I don't recall having tasted this one (though I might be mistaken). I'll have to ask around for am account of its flavor, but my grandmother mentions that it is fibrous. It grows wild in the mountains of Puerto Rico and is wild-harvested here. So why have I rejected it? Because it is a carrier of a virus that is a very nasty disease of D. trifida (and also affects other species, to varying degrees). That's a big risk for a crop that's probably not very decent (though it requires no special preparation). Why the question marks? Well, I've yet to find out if the seeds carry the disease. If they don't, I wouldn't mind trying my hand at this species. But first I need assurance that I'm not endangering my other yams before I'd be willing to even consider it.


So this is a taste of what I wish to achieve. There's a lot of edible yam roots out there, and I wanna grow as many as I can, especially the better types, and help get them to other interested growers. It seems absurd to me that something as widespread, productive and gastronomically wholesome as the air potato was so hard for me to find in the first place. And it seems even weirder that other good yams (which don't have the same legal issues) seem even harder to find. So let's get a good germplasm collection up and running to get these species into the hands of other hobbyists. The more people join our exchange network, the better.

WOW!!! You are The Yam King!  ;D
Thank you very much for this great info!

Haha, the Yam King... I like the sound of that. But surely the original document authors have me beat in that regard. I remember that when I first got into agriculture, having decided to become a farmer, I'd facetiously tell my friends that my work would be growing yams in the hillsides. I never imagined that I'd actually be dreaming of doing just that. Oh well, yams are only part of it, I love all edible crops. I hope I'll be able to get a piece of land soon.

I took some photos of the backyard, particularly the yam trellises. Please disregard the mess, I need to clean up soon.  ;)

Here's the pvc trellis, still under construction (just a couple of posts so far). I'll add some t-jointed side bars on top, and link everything with clotheslines. I'll also link it to the bamboo trellis, with which it's perpendicular at the corners.

Here's the bamboo trellis, with some very vigorous bulbifera vines reaching past it and into the big pigeon pea bush in the side yard... They'll be reaching the Açaí palms soon!

The bulbifera tote (six plus the original rotundata and a trifida), the tomato tote (with a second rotundata strain, a trifida and the two alatas - one of them the purpurea strain) and the Lerén tote (three of these, with four potato mints and six trifidas):

And a nice view of the rotundata growing up alongside the bulbifera:

I'll be adding more totes over time, as well as a few buckets for those that I'd like to grow more isolated or compact (like the polystachya & hamiltonii). The green tote off to the side (currently housing some turmeric that I'll move to the ground) will house the Hodgsonia vines.


I forgot to post a pic of my dried up mystery bulbils, so here it is:

And the links to the pentaphylla bulbils (I bought the first one):
Link 1, and Link 2.

Also, either I misread the information or it was outdated, because I found two to four extra Yams from Madagascar that are allegedly edible: D. acuminata and/or D. maciba, and D. alatipes and/or D. bako.

Hi! That's great! But this bulbs rehidrate and growth?

I did rehydrate them prior to sowing, but my concern was the extent to which they were dried, the fact that some were apparently squished in the package, and the fact that all of them had already sprouted, and the sprouts were nothing but dried twigs at this point. They'll probably succumb to rotting, but I'm still praying for a miracle.

I got my D. hamiltonii seeds yesterday, I think there were like 30 in the package. I planted 10 in a jar covered with plastic wrap to preserve moisture, and soaked the rest, per the instructions. I'll be planting those soon in a plastic pot.


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