- Sir Nathaniel Bacon’s painting records the arrival of American crops in early modern England. And the cookmaid gets equal billing.
- North America’s bison survived near-extinction, but how much of its genetic diversity is left? Past and present DNA is helping reconstruct what was lost, with implications for how what remains is conserved and managed.
- China’s wild rice collection in Hainan now holds more than 15,000 samples. A genetic treasure trove, but its value ultimately depends on what breeders can make of it. Much like what’s left of bison diversity.
- Mycorrhizal fungi form vast underground networks that support plant life and store carbon. A new global map begins to show their extent, and just how much of this biodiversity remains overlooked.
- Africa’s herbaria hold centuries of botanical history, much of it still effectively invisible. Specimens can reveal shifting plant distributions and overlooked species. First, though, someone has to do the painstaking work of getting the data online.
- Africa has done painstaking work on seed laws, but getting good seed to farmers remains hard in practice. The gap between policy and delivery is stark, and commercial companies need to work alongside farmer-managed seed systems, not pretend they don’t exist.
Ducks walking in a row
The League for Pastoral Peoples and Endogenous Livestock Development has taken the FAO global livestock distribution maps and added information on the pastoralist groups that keep each species. That goes with other fascinating interactive online maps they have on threats, migration routes, and more.
Which gives me the opportunity to point out that there is such a thing as duck pastoralism, for example in Tamil Nadu:
Ducks can walk a maximum of a kilometre a day. For longer distances, the rearer hires a lorry. Ducks from Tamil Nadu migrate as far as Mangalore and Bellary in Karnataka, Cuddapah in Andhra Pradesh and Ernakumlam in Cochin, and as far as Goa, 850 km away on the west coast. Small-scale rearers may pool their flocks and hire a lorry. The duck rearers often migrate with their families . Only school going children stay back in their native home with grandparents or relatives.
I’d really like to see that one day.
The chocolate formerly known as lost
The Quest to Save the World’s Most Coveted Chocolate is an engaging story in Smithsonian Magazine about Ecuador’s ancient, iconic Nacional cacao. It was published three years ago, but I only just came across it. It rang a bell, so I went back through the archive. And there was lots more there than I suspected. Again in celebration of our twentieth anniversary, let’s go through it.
It all started in 2009, when Jeremy first described how witches’ broom had devastated Nacional cultivation in the early 1900s, how breeders responded, and how farmers eventually widely adopted the more productive and resistant, but much less tasty, new variety known as CCN51. Nacional basically disappeared.
But not totally. In 2011, we Nibbled the rediscovery of Nacional populations in northern Peru by a USDA team, as reported in the N.Y. Times. A glimmer of hope, perhaps?
In 2015, Jeremy returned to the story. We learned that more than half of Ecuador’s cacao trees were then CCN51, which of course made the industry again vulnerable to the next disease. And, even worse, that the chocolate they produced tasted like “rusty nails.”
But now — thankfully — comes a much happier chapter, nicely described in the Smithsonian piece.
Encouraged by the discovery of Nacional in Peru, a motley crew of conservationists, chocolate makers and agricultural scientists went looking for it in Ecuador. In 2013, they found a grove of century-old trees in a coastal valley called Piedra de Plata. DNA showed that nine of 47 trees they sampled were genetically pure Nacional. They established them in a field genebank in 2018, and started producing planting material for interested local farmers.
More than 30 families are now working … to reforest their lands using seedlings from the nearly extinct tree. The rebirth of this once-lost treasure isn’t just a miracle for the chocolate-loving world — it’s also a milestone in reviving the rich heritage of Ecuador’s coastal forests and farming. And it may even offer hope for saving other endangered trees worldwide.
The plan was that within three years the nursery would be producing 5,000 Nacional seedlings annually. That would be about now. Alas, I was not able to find an update, but I do hope they’re on track.
The moral? Conservation pays — especially when what you’re conserving makes chocolate that doesn’t taste like rusty nails.
Cassava, revisited, and revisited again
Cassava has been a persistent thread through this blog since the beginning. It first appears as a staple with a dark side: capable of keeping people fed, but also of causing a nasty disease under some conditions. Over time, it resurfaced repeatedly, showing how one crop can illuminate many of the key issues in agrobiodiversity conservation and use. As part of our anniversary celebrations, let’s pull some posts out and see how that might work…
An early post we called Detoxifying cassava looked at the complex ways konzo epidemics in Africa are linked to the consumption of bitter cassava. A later Nibble pointed to a very digestible (sic) introduction to cassava and cyanide. And Manihot esculenta, I presume? widened the lens historically, drawing on Dr Livingstone’s Zambesi Expedition papers to show how he understood cassava’s diversity, its promise and its danger back in the day.
Several posts over the years have looked at how well we now know and conserve the diversity of the crop. Gaps in cassava collection in Africa highlighted sounded an alarm: eastern and southern Africa seemed to be under‑represented in international genebanks. Later, More on cassava germplasm from Brazil and an earlier post compared the geographic distribution of CIAT’s genebank holdings with the that of both accessions and cultivation in Brazil, illustrating how national and international collections overlap — and where they don’t.
A post on safety duplicating germplasm collections explained the mechanics of backing up diversity, using Embrapa’s genebank as a concrete example. It also included a reference to the global cassava conservation strategy, during the development of which I got schooled on the diversity of the crop. And a paper on sources of pest resistance in cassava we included in a Brainfood showed the value of genebank holdings, identifying landraces in CIAT’s global collection with resistance to thrips, mites, and whiteflies.
This particular arc culminates in a summary of two papers on 50 years of cassava conservation at CIAT, which looks at that genebank from both ends: what went in over five decades, and what actually came out in breeding. A recent Nibble notes that cassava’s diversity is spread across multiple genebanks, and why that’s a good thing, up to a point.
Then came the TME 419 saga: Is there more than one TME 419 cassava? unpacked confusion around an IITA genebank accession number; I say TME 419, you say TMe‑419 revisited the same named clone in Nigerian fields years later. Another intricate tale centred around how some modern varieties got their resistance to post-harvest rotting. Spoiler alert: a wild relative was involved.
Genebanks, however, are not the full story. Cassava’s diversity also has to survive in farmers’ fields, where diseases constantly test its resilience. An early post, Ho hum … another deadly disease, placed cassava brown streak virus (CBSV) alongside then emerging threats like Ug99 wheat rust. CBSV was duly much in the news a few years later in 2011, and we were of course all over it, though not always one hundred percent correct in our judgements. That’s what the comments are for.
A Nibble on cassava pests questioned the crop’s “indestructible,” Rambo-like image as new problems appeared in Southeast Asia and elsewhere. An experiment on cassava degeneration, Twitter‑style focused on what to do about the widespread viral infection of cassava planting material across Africa, which badly affects performance. And a Nibbles roundup on cassava bad and good news captured an apparent mismatch between FAO worry and CGIAR optimism back in 2011. Maybe we should do an update on that, now I think about it.
Another theme has been how the crop is promoted, produced, and woven into everyday food systems today. In Cassava on a roll? I traced production ups and downs in Kenya, intrigued by seeing new products in supermarkets on my return to the country. I followed that up with The flour of Kenyan agrobiodiversity marketing, which shows cassava (with finger millet) being used to diversify staple flour, connecting conservation to real products and diets. And a Nibble on Ugandan cassava from a couple of years back highlights local innovation in value chains, if you interpret it charitably. No doubt all part of the African cassava revolution touted by Forbes in a 2023 Nibble.
I hope this roundup of our past encounters with cassava, incomplete as it inevitably is, has given you a little taste of what twenty years of this blog have been about: following stories as they unfold, picking up old threads, occasionally digging really deep, other times not deep enough. Do search for your favourite crop in the archive, and tell us what you come up with.
Brainfood: Nutrition edition
- Role of indigenous foods in addressing malnutrition and diet-related diseases in Africa: a systematic review. Traditional foods contribute to dietary diversity, micronutrient intake and food security. Nutrition policy should pay more attention to what people used to eat.
- Regenerative agriculture for dietary diversity and food security in Zambia. Soil-focused regenerative practices are associated with more diverse diets, through a mixture of production, income and market effects. Soil health has a dietary dimension.
- The Relationship among Food Environment Types, Diet, and Nutrition Outcomes in Women, Children, and Adolescents from Low- and Lower-Middle Income Countries. What surrounds people matters as much as what they grow: food environments influence dietary diversity and nutrition in complicated ways, but access to wild foods is usually a good thing.
- Allele-specific expression reveals complex regulatory divergence underlying fruit phenotypic differences between cultivated and wild tomato species. Wild tomato relatives harbour genetic variation for sugars, volatiles and other flavour traits that domestication left behind. A reminder that “improvement” can be a process of subtraction. Not nutrition you say? I bet flavour is connected with nutrition — in complicated ways.
- Large-scale phenotyping and multi-trait selection identify low-methane Napier grass accessions under contrasting environmental conditions. Napier grass accessions differ substantially in methane yield, digestibility and other traits. Feed diversity could help reduce livestock emissions without sacrificing everything else. Cows need better nutrition too.