Agricultural Biodiversity Weblog

August 18, 2026August 18, 2026

A picture is worth a thousand descriptors

For decades, germplasm characterization has relied on people looking at plants, seeds and fruits and recording what they see; first on paper forms, more recently admittedly on tablets and the like. I’ve done that myself, and let me tell you, recording the colour of taro stems on bits of damp paper in the middle of a forest clearing in Vanuatu is no fun.

Lately, thankfully, the camera has been taking over.

A recent overview of new tools for plant genebanks highlights digital photography as a way of capturing standardized information on the colour, size and morphology of seeds and other plant parts, alongside more sophisticated technologies such as hyperspectral imaging and mobile field sensors. The attraction is obvious: instead of recording a handful of descriptors by eye, images can capture a much richer set of characteristics that can subsequently be measured and analysed at your leisure.

The potential is particularly striking for fruit crops. A new study of heritage apples used controlled multi-view imaging to characterize about 350 accessions over three years and two locations. Fancy maths achieved 95% accuracy in distinguishing 38 cultivars, rising to 99% when images of three fruits were combined.

And the technology does not necessarily require sophisticated equipment. In a recent demonstration with beans with complex colour patters, Miguel Angel Acosta Chinchilla used ordinary photographs, image pre-processing and clustering algorithms to extract dominant palettes and colour distributions.

We’re moving from a limited number of human-defined descriptors to infinitely explorable machine-readable phenotypes. An image can preserve information that nobody thought to score at the time, and algorithms can return to it later to measure traits that were not originally part of the characterization protocol. For genebanks, that could be transformative. A photograph taken today may become a source of data for questions that don’t actually arise until tomorrow.

I wish I had a digital camera with me in that taro patch twenty-odd years ago. Goodness knows what people could be finding in them now.

August 17, 2026August 17, 2026

Mo’ better veggies

In the latest Eat This Newsletter I shared this item, which may be relevant here too.

There’s no shortage of advice that we should all eat more vegetables. They are undoubtedly good for long-term health, and not eating enough vegetables is one of the top five dietary risk factors for disease. And yet, despite all the exhortations and official guidelines, globally around the world people eat only 60% by weight of the vegetables they should. What to do?

The facts above are just some I lifted from a recent paper in the Proceedings of the National Academy of Science: Reversing vegetable biodiversity loss to diversify diets. The authors are a who’s who of agricultural biodiversity and nutrition (many of them familiar to Eat This Podcast). They offer a four-pronged solution, avoiding the whole fruit-vegetable schism with a wise reflection: “Because culinary traditions and nutritional perceptions vary across regions, the specific edible parts and species considered vegetables can differ across cultures”.

Prong 1: Secure vegetable biodiversity for the future. Collect more vegetable diversity and make sure that existing diversity in collections is kept in good working order.

Prong 2: Harness vegetable biodiversity to deliver new varieties. Give farmers, researchers and breeders access to the collected diversity and information about it so that they can improve varieties across the whole range of vegetable species.

Prong 3: Promote vegetable biodiversity to diversify diets. Include more and more different vegetables in meals at school and at home, primarily by linking local growers to school feeding programmes and local markets.

Prong 4: Integrate vegetable biodiversity into policy frameworks for long-term impact. Of course, as night follows day, policy frameworks follow suggestions for action.

The paper is a really interesting read. It emerges from a three-year pilot project in four African countries and summarises a lot of thinking over the years. I’d love to see all countries grasp the four prongs and run with them. But, NGL, and with the greatest respect to the authors, that seems unlikely. Please, prove me wrong.

August 17, 2026August 17, 2026

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.

August 15, 2026August 16, 2026

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.

August 14, 2026

Featured: Fresh for who, and at what price?

Jeremy rides his hobby horses in his comment on my recent ride on my own:

Good point, that improved varieties always depend on existing diversity yet those doing the improving seldom contribute to maintaining the diversity they depend on.

I would add a couple of my hobby horses.

Will ordinary Zimbabweans be able to afford these “fresh” blueberries? Will the blueberries even be available in Zimbabwe. And, as I swelter through another record-breaking heat dome, I’m reluctant to praise any effort that adds to GHG emissions, no matter how puny those may be in this case.