- 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.
Data is not the destination
Mike Jackson’s account of the early molecular work at IRRI’s International Rice Genebank is a nice reminder that the idea of the “genomic genebank” (as he calls it) is not as new as it may sounds. In the 1990s, RAPD and AFLP markers were already being used to identify duplicates, reveal genetic structure and, more ambitiously, to predict which accessions might possess useful traits. It’s the continuation of the trajectory I traced in my recent post on descriptors: from names and human-scored traits to photographs, digital phenotypes, molecular markers and now genomic information, each adding a layer of information that makes the collection more searchable and usable. The question keeps shifting from “what do we have?” to “which of what we have might be useful?”
Jackson’s story is also a key piece of the argument I tried to make in another recent post: preserving options is only the beginning. More, and better, information makes options easier to discover, but discovering an option is not the same as exercising it. The harder question is what happens next: how do we turn knowledge about what’s in a collection into actual selection, testing, breeding, adoption and impact? Data can open the door to better use of genebank collections. It cannot walk through it for us.
And there is a danger here. As our information about genebank collections becomes ever more layered, richer and more precise, it can start to look as though we’re solving the problem of use. We are not. We are solving the problem of finding possibilities. That’s only one part of the journey. A genomic prediction is not a breeding line; a photograph is not a phenotype under farmers’ conditions. The distance between knowing an option exists and actually exercising it still has to be travelled. That is a social and institutional process as much as a biological and technological one, and it starts only when the search is over.
When farming worlds collide
When we think about crops moving around the world — and we often do around here — the Columbian Exchange is the canonical example, and why not? The transatlantic movement of maize, potatoes, tomatoes, cassava, and chili peppers to Europe, Africa and Asia, and of wheat, sugar, coffee, and livestock to the Americas, was profoundly transformative. It reshaped global agriculture and diets more dramatically than any single event in human history after the Neolithic.
But similar, if maybe smaller-scale, “exchanges” happened long before 1492. The deep history of agriculture features several ancient “mixing bowls,” let’s call them, where traditions from different geographic origins met and interacted in fascinating ways. These are natural experiments in how new crops become part of diversified farming systems, and I think they can be especially useful in thinking about “opportunity crops.”
Usually, by opportunity crops we mean local or regional crops that were perhaps once more important, and then declined. Or, even if they were never very important, they could still do more, given the chance, whether for diets or incomes, or resilience: indigenous fruits and vegetables, forgotten grains, traditional tubers, you know the kind of thing. Their local resurgence is a crucial path to diversification, for sure. But those agricultural mixing bowls suggest that crops from the outside also have a role in enriching local farming.
There are no opportunity crops
At least, not in any biological sense.
No plant is born an “opportunity crop.” It becomes one when somebody finds a way to make its particular combination of characteristics valuable, in a particular context.
That does not make the term useless. It can be a convenient way to describe crops whose potential seems underdeveloped, or whose qualities come to matter more under changing climates, diets and markets. But the phrase can also mislead. It can make opportunity sound like something that resides in a species or variety.
But consider the Georgia peach. Today, the US state of Georgia is almost synonymous with peaches, at least to Americans. But it was not always so. The fruit arrived in North America with the Spanish in the mid-1500s1, spreading rapidly through the Southeast from seed, almost weed-like. For generations, peaches were mostly a local resource, made into pies, fed to livestock or turned into brandy.
As William Thomas Okie recounts in a recent piece in Smithsonian Magazine, it took deliberate selection and breeding, better production practices, research, transport and access to distant markets to turn the peach into a commercial industry — and eventually the icon it is today.
The lesson is not that peaches are in any way special. It’s almost the opposite.
When we talk about “opportunity crops” in the Global South, we often seem to be looking for crops that already possess a particular combination of characteristics: nutritious, climate resilient, locally adapted, culturally valued and perhaps capable of generating income.
But why should opportunity be an intrinsic property of a crop?
All crops contain genetic variation. Some of that variation may become valuable because of a new breeding objective, a new processing technology, a change in consumer preferences, a new market or simply changing environmental conditions.
We cannot know all of those opportunities in advance. Nobody knew in advance that the peach presented an opportunity in the American South.
The Georgia peach story also reminds us that an opportunity is not necessarily an opportunity for all. That industry developed within a society shaped by slavery and racial inequality, and its commercial success depended on agricultural labourers who didn’t much share in the value they helped create. If a neglected African crop becomes commercially valuable, who controls the breeding, seed, processing and markets. Who gets paid?
This does not mean that every crop deserves the same investment. Resources are limited, and choices have to be made. But it does suggest that the most useful question may not be “Which crops are opportunity crops?” but rather “Where is there diversity from which new opportunities could be created?”
This is why we need genebanks. They preserve options, not predictions. A crop or variety that looks unremarkable today may contain a characteristic that becomes valuable tomorrow.
Perhaps, then, we should stop thinking of opportunity crops as a special category of crops, waiting to be discovered. The real opportunity lies in maintaining enough diversity across all crops to keep our options open for whatever the future may bring.
Brainfood: The diverse lives and times of crop diversity
- Herbaria viva: proto-genebanks of Mendel’s contemporaries in Moravia. The early 19th century living plant collections of Moravia (the world Mendel grew up in) were a kind of proto-genebank, systematically maintaining and circulating crop diversity decades before genetics had a name.
- Saving evolutionary time: Conflicting planetary temporalities in the genetic diversity debate, 1967–1980. Looking back 50 years, and 50 years after the Moravian proto-genebanks, a historian of science traces how Otto Frankel and Erna Bennett, sounding the alarm on genetic erosion in the 1960s-70s, articulated two competing visions of time and responsibility for safeguarding crop diversity, one rooted in development, the other in collective stewardship of evolution itself.
- Utilization and conservation of plant genetic resources for food and agriculture in China: a systematic review of genebanks and farmers’ seed systems. From history to present-day infrastructure. In China, genebanks and farmers’ seed systems have developed together, but gaps between formal and informal conservation remain. Otto and Erna unavailable for comment, alas.
- The effect of crop genetic diversity to food security among smallholder farmers in the global south and the role of community seed banks: a narrative literature review. Here’s the evidence on how community seed banks shape food security for smallholders, but could do more. That’s the informal system at work for you, Erna would say.
- How community seed banks contribute to climate-resilient seed systems: evidence from Ethiopia, Malawi, and Nepal. Speaking of which, a companion study looks at how community seed banks function in practice, finding they do bolster local seed security and climate adaptation, but with real limits: patchy variety availability, uneven quantities, and occasional genetic erosion of their own.
- Varietal development and rice yield growth in India: assessing IRRI’s germplasm contribution. A new assessment of the contribution of IRRI germplasm to Indian rice breeding comes in at around 11% of annual rice yield growth from 1966 to 2021. That’s the formal system at work for you, Otto would say.
- Improving low-pH and high-aluminum field tolerance in alfalfa (Medicago sativa L.). Also on the breeding front, screens of genebank collections and their derivatives for field-level tolerance to difficult soils bear fruit. Or rather, leaves.
- FAIRness at all costs? Practical limitations in applying the FAIR principles to plant genetic resources data. And finally, a reality check for the data side of all this. Applying the FAIR principles to plant genetic resources data isn’t as straightforward as the mandate suggests, with a number of practical friction points standing between the ideal and actual implementation.