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Not all Andean tubers are potatoes

Our regular reader botany professor Eve Emshwiller makes a plea on behalf of some under-appreciated — though not by her — Andean crops.

“That’s a potato?” asks the heading of the photo gallery called “Potato Variety” in the “Food Ark” feature on the loss and conservation of agricultural biodiversity in the latest National Geographic Magazine. Well, actually, no. No, not all of the images shown are potatoes. Five of the eighteen tubers shown are oca, Oxalis tuberosa, one of the three other Andean tuber crops.

As far as I can tell, the gallery of “Uncommon Chickens” and the one for “Rare Cattle” didn’t include any ducks, turkeys, or goats. People would have noticed. In the case of their “Potato Variety” gallery, on the other hand, they missed half of the story. If they’d gotten it right, they would have been able to educate their readers about more than variation within a single crop. They could have gone on to explain about the values of cultivating a diversity of different species, diversity that far exceeds even that in the amazing native Andean potatoes.

The three “minor” tuber crops may not have gained the worldwide importance of the potato, but for a story that focused on the loss of diversity, these other tubers offer even more poignant examples. In my travels in Peru with the germplasm coordinators of INIA (which currently stands for Instituto Nacional de Innovación Agraria), we came across many places where oca was being abandoned by farmers, due either to severe weevil larvae infestations, or in favor of more marketable crops such as commercial potato varieties.

Among the not-so-lost crops from long-before-the-Incas, are a whole bunch of Andean root and tuber crops (often lumped together as ARTs). Ancient Andean people not only domesticated potatoes in all their incredible diversity, but also other tuber crops from three completely different plant families. For those who haven’t met them yet, the three non-potato Andean tubers are (1) oca, Oxalis tuberosa, of the Oxalidaceae, the wood sorrel family; (2) ulluco or papa lisa, Ullucos tuberosus, of the Basellaceae, the same family as Malabar spinach; and (3) mashua, añu, or isañu, Tropaeolum tuberosum, from the Tropaeolaceae, the family of garden nasturtiums. None of these are closely related to each other, or closely related to the family to which potatoes belong (Solanaceae, the nightshade family). No other area of the world domesticated so many different tubers.

Ancient Andean people also domesticated several root crops as well, which are also each from a different plant family. 1

Don’t get me wrong, I think it is absolutely wonderful that the NGS is featuring agricultural biodiversity in their magazine and online. Maybe it bodes well for another spurt of attention to this theme from magazine journalists — don’t they return to it every 25 years or so?

In truth, people are constantly mixing up the Andean tubers, so it is really no surprise that it is happening again. Ulluco is often mistaken for a colorful potato, and it seems as if oca and mashua are mistaken for each other more often than not. Many of the images online that are purporting to be oca, are not. Meanwhile, oca is often mistaken for a native Andean potato, just as in the case of the five tubers of oca (one of them fasciated) that were called potato by National Geographic. So, this is not an unusual case.

Illustration from: Origins of domestication and polyploidy in oca (Oxalis tuberosa; Oxalidaceae). 3. Am. J. Bot. (2009) Eve Emshwiller, Terra Theim, Alfredo Grau, Victor Nina and Franz Terrazas.
I could go on and on about how oca and the other ARTs are overlooked, even by researchers on Andean crops. Archaeological remains of tubers are too often assumed to be potato, local conservation efforts often ignore the non-potato Andean tubers (but see below), and even the Crop Wild Relative project in Bolivia, incredibly, did not include oca’s wild relatives among its featured taxa.

But, looking on the bright side, at least CIP has a program on ARTs, now prominently displayed on their newly redesigned website, including a brief introduction to the non-potato Andean tuber crops. And I trust that some of the many celebrations of Peruvian food recently featured on this blog certainly must include dishes made with ARTs, in an effort to overcome these crops’ stigma as “poor person’s tubers.”

In fact, perhaps things are better than I thought. See the image in the Food Ark Photo Gallery that has a caption that begins “A nest of hay preserves harvested potatoes and tubers in Pampallacta, Peru.” Pampallacta is part of the Parque de la Papa, yet the tubers pictured are oca again. So, does that mean that the Parque de la Papa is indeed working to preserve the non-potato Andean tubers as well?

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Vote early, vote often…

Many thanks to the World Vegetable Center for running a poll on Jacob’s seeds-with-yoghurt idea. Head on over to their Facebook page and vote!

Alternatively, because we are such Social Media Mavens that we serve even people who aren’t on Facebook, head on over to our own sidebar, over there on the right, and vote here instead. Or as well. Do people who vote here vote differently from people who vote at the other place?

You’ll note that we’ve modified the question ever so slightly, as we’re not sure how many subsistence farmers in, say, Mali, eat store-bought yoghurt. Even with free seeds.

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Rice domestication roundup

In the past few weeks there’s been a number of papers on the genetics of rice domestication. I’ll just give you the main findings here, and leave you to battle with the details on your own. With the help of various other bloggers.

Dorian Fuller did a great job of summarizing the multiple domestication (or indica and japonica) theory at The Archaeobotanist a couple of weeks back. This seems to have the upper hand at the moment. Wild perennial rice is cultivated in wetland margins in the Neolithic Yangtze, and as the water ecology begins to be altered by humans, creating seasonal drought conditions to stimulate seed production, particular adaptations are selected (annuality, short stature, less branching etc.), which leads to the domestication of japonica rice. This is then taken to the area of an independently-domesticated proto-indica, probably around 3800-4000 years ago, and some genes are exchanged. So far, so good, and there is now a pretty comprehensive database of rice archaeology to back up the recent studies of single and multiple genes.

Well, certainly the “genetic and selective basis for domestication” seem to be different for japonica and indica, but another recent paper throws some doubt on the multiple domestication idea. Now, I’ve briefly discussed this with people who know a lot more about rice than I do and it seems the main sticking (as it were) point is the dating of the indica-japonica split to 3,900 years ago. Previous estimate were in the hundreds of thousands of years, supporting the multiple domestication theory, but the problem is that the newer, lower estimate was based on domestication genes only. Lots more argument on the horizon, I suspect.

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Ecoagriculture reviewed, again

It was over two years ago that we mentioned a meta-meta analysis of ecoagriculture. Since then we’ve had Prof. Olivier de Schutter, the U.N. Special Rapporteur on the right to food, weighing in, among other celebrities. Now David Suzuki, no less, tells us about yet another review, with much the same bottom line:

…our review supports the claim that the solutions to the problems of widespread food insecurity and biodiversity loss need not be mutually exclusive, and that it may be possible to address both using appropriate alternative agricultural practices.

Here I just want to throw something else into the mix. We know from yet another recent meta-analysis that there are recognizable socioeconomic patterns to the distribution of infraspecific crop diversity on farm. A study has just been published which suggests that the number of species cultivated by a traditional society can be predicted by latitude, environmental heterogeneity (mainly altitude), and the commitment of the society to agriculture (as opposed to herding, foraging and exchange). Does this mean there are some intrinsic limits to the level of intra- and inter-specific agrobiodiversity a given agricultural system will support? And if so, what does that mean for ecoagriculture in that region?

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Making the most of bitter gourd diversity at AVRDC

Another interesting agrobiodiversity piece in AVRDC’s newletter today:

The AVRDC Nutrition group is locked in a struggle with a cucurbit – and so far, warty Momordica charantia appears to be winning! As part of the project “A better bitter gourd: exploiting bitter gourd to increase incomes, manage type 2 diabetes, and promote health in developing countries,” researchers have begun preparing samples of the vegetable for later laboratory analysis.

Interested? “Like” the project’s Facebook page then!