- New webinar series from the American Society of Plant Biologists will explore how underutilized (or is it opportunity) crops like amaranth can contribute to nutrition, food security and rural livelihoods.
- FARA highlights the tiny West African grain fonio as another crop with potential to improve nutrition, strengthen food systems and create new opportunities for farmers and value chains.
- Taiwanese tea has travelled an unlikely route into northern Thailand. It too was an opportunity crop at one time.
- Ethiopian farmers may have been practising regenerative agriculture for millennia, mixing wheat, barley and other grains in the same field. The Rockefeller Foundation is on it.
- Efforts to restore the Al Qarara Seed Bank in Gaza are offering a small but significant form of agricultural recovery.
- In Nepal, indigenous seeds are losing ground to hybrids, but seed advocates are fighting back.
Conserving the tangle of grapevines
I think we may have already pointed to Conservation gap analysis for wild grapevines (Vitis L.) of the Americas, the latest in a series of papers by our friend Colin Khoury and a rotating assortment of colleagues on the conservation status of the crop wild relatives of the Americas, genepool by genepool. The authors compiled occurrence records for 38 wild American grapevine taxa, and used fancy GIS to infer the overall distribution and environmental niche of each. They then assessed the degree of representation of each taxon in genebanks and protected areas, and hence any remaining conservation gaps. Here’s the headline finding:
We categorize 25 of 38 of the taxa as urgent priority and 10 as high priority for improving ex situ conservation representation. Three taxa are assessed as urgent and 29 as high priority for enhancing in situ conservation. Further action, with emphasis on conservation gap hotspots, is needed to more comprehensively conserve wild Vitis native to the Americas.
Which is pretty clear.
Or is it?
What if “taxa” are perhaps not always the best units of conservation to use in assessing conservation efforts?
That may in fact be one of the implications of a paper that came out just a few weeks after that of Colin and friends: The dynamics of introgression and parallel adaptation across North American Vitis species.
These authors show that introgression and hybridization are pervasive and evolutionarily important across North American Vitis, based on genomic analysis of 639 accessions representing 48 species. About 14% of the average genome shows evidence of introgression, particularly associated with areas where species come into contact. Some taxa usually regarded as hybrid species are in fact better understood as ever-changing hybrid swarms, rather than distinct evolutionary lineages. Most importantly, the authors find that introgressed genetic variants have repeatedly contributed to adaptation in different species. The paper therefore portrays Vitis diversity as a reticulate network — or tangle — of species, populations and gene flow, rather than a set of discrete species.
This has important implications for conservation: hybrid zones and admixed populations may be really significant reservoirs of adaptive diversity. The framework of the first paper might potentially underestimate the conservation importance of regions where these occur, if they contain substantial genetic variation but aren’t well represented by the taxonomic units used in the gap analysis. For example, it might happen that two neighbouring species are reasonably well represented ex situ, but not from the specific regions where they hybridize and introgression occurs.
This suggests a useful next, synthetic step: take the geographic gaps from the first paper and overlay them with the evidence for introgression and gene flow networks from the second. The resulting map could identify not just under-collected species, but under-collected (or under-conserved in situ) evolutionary processes and genetic mixtures. That could be valuable for designing the next Vitis collecting mission.
Brainfood: Mung bean pan-genome, Sunflower resistance, Olive adaptation, Allergic peanuts, Weird coffees, Chinese tea, Measuring selection
- Graph-based pan-genome reveals structural variations associated with agronomic traits in mung bean. Pan-genome captures extensive structural variation missed by a single reference genome, providing new targets for mung bean improvement.
- Wild genes to the rescue: high-throughput genomics reveals the wild source of broomrape resistance in sunflower. Combining high-throughput root phenotyping with genomics identifies wild introgressions underlying broomrape resistance in sunflower and exposes valuable adaptive variation for breeding.
- Genomic insights into the local adaptation of spontaneous olive trees in the Mediterranean Basin highlight the need for conservation planning in the face of global change. Genomics of wild West Mediterranean olive trees reveals patterns of local adaptation across temperature and rainfall gradients that it will be important to conserve as climates change.
- Genetic regulation of major immunogenic protein accumulation in peanut seeds. Genomics provides targets for breeding peanuts with reduced allergenicity.
- Genomic elucidation of hybridization between Liberica and excelsa coffee and its implications for coffee crop development. Genomics confirms that Liberica and excelsa coffee readily hybridize and produce fertile, genetically diverse offspring with intermediate agronomic traits, a possible source of diversity to broaden coffee’s climate resilience.
- Simple sequence repeat (SSR) marker-based genetic diversity and population structure of large-leaf tea germplasm across four major tea-producing regions of Yunnan, China. Genomics of Yunnan’s large-leaf tea germplasm finds substantial genetic diversity but remarkably little regional differentiation, showing that seed propagation, natural crossing and human movement have maintained genetic connectivity across tea-growing regions.
- Measuring maternal line selection driven by differential survival in ex situ collections for plant conservation. A new method distinguishes random mortality from selection among maternal lines in ex situ collections, offering conservationists a way to detect whether plant deaths are systematically eroding the genetic variation they are trying to preserve. And no genomics involved.
A Babel of agrobiodiversity
“The rise and fall of language diversity through the Holocene” by Blasi, Hamilton, Gray & Bowern, published in Science last month, does something I really love. It complicates a standard narrative.
The received story of language diversity is that it has been declining steadily for centuries, largely driven by colonialism and globalization. But direct evidence is scarce and recent: writing only reliably takes us back about 6,000 years. So the team combined ethnographic data from 171 hunter-gatherer and fisher societies, paleodemographic estimates of global population, and statistical and social-computational modelling to reconstruct plausible trajectories of global language diversity over the 12,000 years of the Holocene, which began after the last major ice age, triggering the birth of agriculture.
At the beginning of this period, they estimate there were roughly 4,500–6,200 languages. That’s actually fewer than the roughly 7,500 languages spoken today. Language diversity then increased through most of the Holocene, driven by the population growth engendered by agriculture, reaching a peak between about 1,000 and 3,000 years ago, when the models suggest that tens of thousands of languages may have existed. That’s an order of magnitude more than today.
Then came a major collapse. The authors argue that the decline in linguistic diversity began with the expansion of large states and empires, long before European colonialism. Expanding populations and their languages, cultures and institutions displaced smaller ones. Today’s languages are therefore “survivors of a massive and highly selective historical bottleneck.” They persist because the populations speaking them expanded. Extinction, the authors argue, has shaped linguistic and cultural diversity far more — and for longer — than we have appreciated.
Now, there are obvious caveats. The authors are modelling linguistic diversity, not measuring it. Their estimates depend on heroic assumptions about early ethnolinguistic group sizes, global population and the relationship between population and language number. Regional histories could have been very different, and the model can’t reconstruct individual episodes of extinction caused by war, disease or environmental change.
But the paper provides a provocative template for thinking about diversity more generally. It suggests that population growth can initially generate diversity; but expanding societies can subsequently erase it through homogenization.
And that makes me wonder about agricultural biodiversity. You saw that coming, I’m sure.
I’m not suggesting that crop diversity followed the same pattern as language diversity through the Holocene. We simply don’t have the evidence to say that, though it’s an intriguing thought. But could we borrow the methodology? Could we reconstruct plausible trajectories of crop or agricultural-system diversity from fragmentary archaeological, ethnobotanical, genetic and demographic evidence?
Rather than assuming that agricultural diversity was vast and stable in the distant past, happy in its Vavilovian centres, and has been declining recently, perhaps we might end up complicating the familiar genetic erosion narrative too. That would be worthwhile. And fun.
Brainfood: Avocado history, Brazil commuity seedbanks, Citizen science, Agroecology double, Indigenous knowledge, Turkish seeds, Swiss biodiversity
- Ethnobotanical and genetic assessments of Central American avocado landraces reveal novel sources of biodiversity and ancient migration patterns. DNA from landraces, and interviews with farmers, show that people transported and cultivated avocados across the Americas long before European contact, with landraces from lowland Nicaragua and Honduras in particular showing evidence of ancient migration from South America.
- The Circle of Seeds: An Ethnography of Seed Guardianship and the Making of Agroecological Futures in Paraná, Brazil. Community seed banks depend on relationships of care, reciprocity and collective labour, especially among women farmers, and not just on knowing how to store seeds properly. Though that helps, clearly.
- iNaturalist as a Tool to Improve Agroecological Biodiversity Knowledge: An Ecuadorian Case Study. A citizen science platform can strengthen agroecological biodiversity knowledge, but more efforts are needed to engage farmers.
- Are agroecological practices pro-poor? Evidence from smallholder farms in Zimbabwe. Farmers using agroecological practices were generally wealthier and their farms were more diverse in crop and livestock species, but the association between the use of improved practices and diet outcomes was inconsistent.
- Regenerative agriculture for dietary diversity and food security in Zambia. Agroecological practices were positively correlated with improved dietary quality and food security, including (though not exclusively) through farm production diversity. No word on the wealth of the farmers involved.
- Indigenous Peoples’ knowledge systems and practices for climate survival. Indigenous knowledge systems, including of farmers, offer tested approaches to climate adaptation and resilience that warrant a central place in responses to environmental change.
- Guardians of Agricultural Biodiversity: Farmer Perceptions and Sustainability of Local Seed Varieties in Turkish Highlands. Farmers continue to maintain local seed varieties, driven as much by social, cultural and market considerations as by agronomic performance. But they need support.
- Religion, spirituality and faith of Swiss farmers in relation to biodiversity-linked farming behaviour. Farmers’ religious and spiritual values can shape biodiversity-friendly management decisions, showing personal belief systems are important in conservation. Even in Switzerland.