- WorldCuP: A database of checklists documenting the World’s Cultivated Plants and their distributions. Cool new database records 1,444,325 occurrences representing 91,358 accepted cultivated plant species across 2,718 regions in 156 countries. Geographic coverage is extensive but uneven, with notable gaps in parts of Africa, southwest and central Asia, and Oceania. Most of the taxa recorded are not in existing major crop and useful-plant databases.
- Integrating multiple disciplines to locate the origins of domestication of crops. Combining evidence from botany, biogeography, genetics, archaeology, linguistics, and history overturns the traditional Mesoamerican hypothesis for cacao origins, supporting domestication in western Amazonia, probably involving multiple events. Peach palm’s domestication is best placed in southwestern Amazonia. Cupuaçu remains unresolved. Now for the other 91,355 species.
- Plant Species Mentioned in Abrahamic Scriptures: Implications for Biodiversity and Traditional Agriculture and Horticulture. Olive, grapevine and fig, together with cereals such as wheat and barley, occur prominently across the three scriptural traditions examined, while date palm is particularly prominent in the Qur’an. Not clear whether scriptures qualify as checklists.
- Crop landrace conservation, status, challenges and motivations in Great Britain. A national inventory (checklist even) identifies 566 landrace populations maintained on farms by 197 growers, alongside 1,876 British-origin genebank accessions, representing a total of 1,201 distinct landraces. Cereal and vegetable landrace cultivation has gone up since 2004, but forage diversity is increasingly threatened. Climate change, labour shortages and lower yields are the main challenges reported by growers.
- An inventory, threat and conservation assessment of UK wheat landrace diversity. The UK currently has 27 wheat landrace varieties growing on more than 700 hectares, an increase in both variety numbers and cultivated area since 2009. Interviews with 50 farmers identify insufficient market demand and limited seed availability as key constraints. So, not climate change, labour shortages and lower yields.
- Strong differentiation between source and ex situ populations of rare plant species revealed by next-generation sequencing. Across four rare plant species, ex situ populations showed significant genetic differentiation from their wild sources despite only one generation in cultivation, while overall genetic diversity and inbreeding did not differ significantly. Unrepresentative seed collection, unconscious selection during propagation or genetic drift could explain the differences. Something to test on all those British landraces, labour permitting?
- Rethinking the vineyard of Santorini in a changing climate and preserving an historic wine region. Recommends a staged transition from vineyard recovery to ecological regeneration, prioritising soil organic matter, drought management and indigenous grapevine diversity. Sounds like lots of labour will be needed.
- Conservation dilemmas: Xylella fastidiosa and the future(s) of olive farming. In Puglia, disease management is pushing olive farming towards competing futures: intensive, mechanised production vs the preservation of ancient trees as cultural landscapes. The fate of traditional groves depends less on technical disease solutions than on whether markets, subsidies and labour arrangements make their continued care economically viable. Well that doesn’t sound promising. Maybe try prayer?
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.
Nibbles: African food systems, Uganda cassava, Uganda pastoralists, Butternut conservation, Seed transfer zones webinar, Frozen Zoo, India fish genebank
- Swapping maize for indigenous crops won’t fix African food systems designed around markets and policies that still favour a narrow range of crops.
- Cassava is both a food security fallback and a commercial crop in Uganda, but disease, climate change and declining diversity make its conservation an increasingly urgent form of insurance. But what about the markets and policies?
- When livestock and crops fail, Ugandan pastoralists draw on wild plants for food, underlining how much food-system resilience still sits outside the formal agricultural system, with its markets and policies.
- The Morton Arboretum is using living collections and genetic research to help the threatened butternut tree cope with changing conditions.
- Webinar discusses global approaches to seed provenancing and transfer zones, useful for anyone who wants to move native plants without moving the wrong genes. Butternut very interested.
- San Diego Zoo Wildlife Alliance’s Frozen Zoo preserves genetic material of plant and animal species that may disappear, from DNA to cells to organisms. Butternut volunteers.
- New Indian facility combines ex situ fish conservation with community aquaculture. Good model for much of the above?
Nibbles: Historical photos, Belgian pears, Miombo fruits, Kenya seed treble, Nepal landraces, Women
- Haga Hideo’s 1950s photos of Fukushima farming rituals are now being used to revive them: ex situ conservation, but for culture.
- Long before photography, or “pre‑breeding” was a buzzword, Belgian pomologist Jean‑Baptiste Van Mons was running massive pear selection trials and gifting us Beurré Bosc and Doyenné Boussock.
- As Southern Africa’s miombo woodlands shrinks, scientists are cloning wild trees so the fruit — and food security — outlive the forest. Now for the pre-breeding.
- Greenpeace Africa’s Seed Project makes the case for indigenous seeds as a route to farmer independence. And you can help.
- And oh so coincidentally, a network of community seed banks in Kenya is rescuing indigenous seeds so the diversity is still around when opportunity (or crisis) knocks.
- Also in Kenya, the national genebank’s collectors are racing to secure opportunity crops.
- Nepal’s indigenous crops and landraces are at the same time more needed than ever, and under threat. So, much like in Kenya.
- The Alliance of Bioversity and CIAT says women are at the center of sustainable food systems; the fine print adds: “as they have always been.”
Brainfood: From data to action
- A three-decade-long analysis shows rising threatened species and responsibility gaps in global supply chains. Data says that we must make responsibility for biodiversity traceable from production to final demand.
- Development of an evidence-based integrated germplasm prioritization framework for conservation and breeding. Data says: here’s how to extract some defensible conservation and breeding priorities from this large collection.
- A methodological framework for the standardised evaluation of olive genetic resources: GEN4OLIVE harmonized protocols. Data says that we should standardise phenotyping across countries to make olive germplasm more useful in breeding.
- High-throughput phenotyping of Bambara groundnut [Vigna subterranea (L.) Verdc.] seed morphometrics using videometer. Data says that we should use multispectral imaging to really speed up seed characterization and breeding in Bambara groundnut.
- Predicting the cross-continental spread of the cassava brown streak disease epidemic in sub-Saharan Africa. Data says that we must strengthen surveillance and delivery systems for clean planting material before cassava brown streak disease reaches Nigeria.
- The Sustainability of Robusta Coffee Under Global Change—A Review. Data says that we must match robusta production to genuinely suitable environments, plus invest in lower-input cultivation and alternative coffee species.
- Borassus Akeassii Facing Societal and Environmental Challenges: Case Study of the Gouin Society of Southwestern Burkina Faso. Data says that we need to conserve this multipurpose palm once central to Gouin livelihoods together with the local knowledge and practices that make it useful.