- Frafra potato is having a moment: an indigenous West African tuber, adored locally and mostly ignored by science, out looking for its big commercial break.
- Speaking of breakthroughs, this bus driver found his own, swapping the wheel for seed multiplication and turning five acres into a livelihood, proof that sometimes the missing link in a seed system is just someone willing to do the unglamorous middle bit well.
- Which is, per Farming First, precisely Africa’s problem at scale: only 2.5% of smallholder seed in Sub-Saharan Africa comes from formal seed companies, so a few million more bus-driver-style multipliers wouldn’t hurt.
- Meanwhile in the Balearics, the opposite direction of travel: the local seed bank is expanding to rescue tomatoes, onions and broad beans, and is looking for farmers willing to take them back.
- Indigenous fruit trees in Malawi turn out to fight malnutrition and biodiversity loss at once. Happy coincidence?
- Getting those trees into the ground well needs the same unglamorous groundwork as any good crop seed system: a Mongabay commentary argues that restoration campaigns skipping Indigenous and local seed knowledge are optimising for trees planted, not trees that survive.
- And once you’ve got the saplings in the ground, you might want to monitor how they’re doing: enter Bruno, a pushcart rigged with mobile phones that can collect field data. And not just for breeders.
- Finally, proof that not all genetic-resource hunting needs a genebank: Brussels brewers are getting people to comb the city for wild yeast, because the raw materials for a proper lambic turns is hanging around in urban trees.
Brainfood: Tree conservation from assisted migration to cryo
- The potential effect of megafaunal extinctions on modern conservation of horse chestnut Aesculus hippocastanum. The extinction of large seed-dispersing mammals (i.e. elephants) may explain why horse chestnut failed to recolonise Europe after the last ice age, pointing to assisted migration as a conservation option.
- Mapping melliferous tree species in Kenya via one-class classification with hyperspectral unsupervised domain adaptation. Hyperspectral remote imagery and fancy maths can accurately identify and locate Kenya’s honey trees, potentially supporting both conservation and beekeeping. Brave new world. Elephants not involved.
- Everyday agroecologies in the Mixteca Alta, Mexico: gendered knowledge and practices in homegarden agroecosystem management. Women’s knowledge helps sustain homegardens as reservoirs of agrobiodiversity and climate-adaptation spaces, embedding many interesting wild and cultivated trees, along with much else, in wider systems of knowledge and resource management.
- Integrative DNA barcoding and multimethod species delimitation reveal marker performance in the genus Ficus L. (Moraceae). Takes on the old taxonomic problem of where one fig species ends and another begins. Ficus is an especially resonant group for today’s tree-themed roundup: taxonomically challenging, ecologically consequential, economically and culturally important, tied to famously specialised pollination relationships. “Integrative” means the usefulness of a DNA marker must be tested against other evidence and against the particular boundaries one is trying to recognise.
- Chloroplast phylogeographic analysis guides the source tracing and conservation strategies of the endangered Magnolia kwangsiensis Moving down one biodiversity level, mapping maternal genetic structure helps identify appropriate seed sources for conservation and restoration, rather than treating all populations as genetically equivalent. Next comes feeding the seeds to passing elephants.
- Development of a simple and easily interpretable cultivar identification system using 18 insertion/deletion (InDel) markers in Japanese pummelo (Citrus maxima). Really simple markers can identify Japanese pummelo cultivars, and even reveal clues about their parentage.
- К 100-летию отдела генетических ресурсов плодовых культур ВИР. (On the 100th Anniversary of the Fruit Crop Genetic Resources Department of VIR). A century-long institutional case study in tree (ok, and shrub) conservation at scale: some 19,000 fruit, nut and berry accessions now held in field genebanks across ten Russian field stations, each sited in the climate zone that suits what it conserves.
- Cryopreservation strategies for trees: Leveraging organogenesis and somatic embryogenesis for effective conservation. Combining ultra-low-temperature storage with making shoots or roots from an explant tissue and making embryo-like structures from non-reproductive cells offers ways to emulate seeds when the real things cannot be easily stored in the usual way, field genebanks cannot be guaranteed to last 100 years, and there are no elephants around.
Nibbles: Mango breeding, Cambodian peppers, Cold genes, Geechee cowpea, Navajo genebank
- Blue mangoes.
- Kampot pepper.
- Antarctic flowering plant.
- Sapelo Island red pea.
- Navajo seed data.
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.
The fruits of migration
As chance would have it, following my recent speculative foray into the possible connection between language and crop diversity, an essay by the great Andrea Wulf 1 has just appeared that tells the story of how a remarkable German naturalist used breadfruit and linguistics to work out Polynesian migration patterns long before DNA or archaeology could confirm them.
George Forster sailed with his father aboard the HMS Resolution on Cook’s second voyage (1772-1775) and encountered breadfruit across the South Pacific. He noticed that the trees were seedless and could only be propagated by root cuttings. And also that there didn’t seem to be wild breadfruit trees anywhere in the islands. That meant every tree he saw, and there were many of them, had been deliberately planted by people.
Digging through the university library back in Göttingen, Forster later found that wild, seeded breadfruit with little flesh do exist, but in Southeast Asia. If the Pacific islands only had the improved, seedless types, he reasoned, they must have been carried there by people. That was proof both of sophisticated Polynesian plant management and of a migration route running from Southeast Asia eastward across the Pacific.
Forster combined this with careful attention to language. He deduced that most Pacific languages he encountered were dialects of a single root language, with small, systematic sound shifts. He and his father also charted how the presence of Malay loanwords decreased the farther east an island was located, which suggested that islands closer to Southeast Asia — the home of Malay — were settled earlier.
Where his fellow naturalist Joseph Banks saw the breadfruit purely as an economic resource (later lobbying to transplant it to the West Indies to feed enslaved plantation workers, hence HMS Bounty and all that), Forster saw it as historical and ethnographic evidence. That’s a strikingly different, more humanistic and — to me at least — more appealing way of reading a plant.
Wulf then jumps forward to modern archaeology and genetics, which broadly confirm Forster’s reconstruction. There was an initial human population in the region of Papua New Guinea dating back 45,000 years. This was followed by a second, Austronesian-speaking wave migrating out of Taiwan and thereabouts around 3,500 years ago. They travelled by the stars in “outrigger or double-hulled canoes loaded with hogs, chickens, root vegetables, coconuts, bananas, and breadfruit seedlings.” And they mixed with the descendants of the earlier wave through Melanesia. Their own descendants eventually reached Fiji, Samoa, Tonga, and, much later, Tahiti, Hawaii, Easter Island and New Zealand.
The essay closes by tying this to Tongan historian Epeli Hau’ofa’s idea of “Oceania” — the Pacific not as scattered, isolated islands, lost in a vast ocean, but as one interconnected “sea of islands.” Exactly what Forster intuited two centuries before it became conventional wisdom.
We’ve blogged a lot about breadfruit over the years. Check out the archive. And in particular listen to the recently-retired Dr Diane Ragone describe her 40-year journey to understand this remarkable tree.