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Sesame: not an open and shut case

Lack of time sometimes casts an interesting item as a Nibble, so it is good to have time to draw attention to a FARM-Africa project in Tanzania. A recent post on the Farm Africa blog updates a sesame project. The chair of the Sesame Marketing Group in one of the target villages explains:

[E]ven though the community has been harvesting sesame for years one of the big problems they face every year is the size of the sesame crop. The villagers tend to use a mixed bag of seeds, which means that the plants grow at different rates. As a consequence they are unable to harvest a large crop, or to sell in bulk.

He hopes that by using the seeds provided by FARM-Africa the villagers are able to produce a larger crop and generate a profit.

Looking back at the overview of the sesame marketing project, there are clearly some very good things in it. Farmer Production Groups will be helped to learn more about sesame production, will get equipment to measure oil and moisture content, will be connected with markets and market information, will be trained to clean and store seeds effectively, and much more besides. But the key seems to be the distribution of improved sesame varieties, “giving them the chance to grow a larger, higher quality sesame crop”.

All extremely worthwhile, and I for one hope that the project is an enormous success. But I would feel even better about it if the project included banking the local unimproved “mixed bag” of seeds. There are ex situ sesame collections, and efforts have been made to whittle them down to core collections. Before FARM-Africa’s successes cause Tanzanian growers to give up on their old varieties, I’d like to be assured that they are already being conserved somewhere.

Instead of all which, had I been pressed for time, I would simply have written “Open Sesame”.

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Featured: Archives

Hearing about the Jack Hawkes Archive, Professor Adi Damania bemoans the fate of another giant’s papers:

Jack R. Harlan’s papers … are scattered between his students, sons, and admirers here at University of California, Davis. His papers have survived a boat sinking in New Orleans harbor and the Katrina floods. We are seeking funds to do a biography.

What will happen when someone’s papers are just bits? Will they be easier or harder to assemble?

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Mining the internet for threats to agrobiodiversity

Late last year I blogged about what an early warning system for erosion of agricultural diversity might look like. I was thinking of an active reporting system, but today Conservation Maven reminds me of a paper published a few months ago that suggests that a more passive approach might also be possible. The authors ask the question: Can researchers who are interested in ecological monitoring tap into … increased flows of information by “mining” the internet to detect “early-warning” signs that may signal abrupt ecological changes? The paper is behind a paywall, but I’ve ordered it. Once I read it, I’ll report back whether web crawlers have a future in genetic erosion monitoring.

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More on future-proofing germplasm collections

A reply to Walck & Dixon from Brian Forde-Lloyd, Nigel Maxted and Luigi Guarino.

ResearchBlogging.orgIn Walck and Dixon’s opinion (Nature 462: 721, 2009) it’s ‘time to future-proof plants in storage’, but how novel and useful is this idea? 1 Few would argue with the principle that we need to maximise the range of genetic diversity conserved ex situ, but some of the issues raised need further consideration.

1. Collecting species at the limits of their ranges could be a good idea — this could be where adaptations most likely to be occurring; for wild wheat populations, genes thought to be adaptive to biotic and abiotic stress have been found to be highly variable in some ecological circumstances (e.g. wild wheat in Israel). But, more generally, population genetic theory suggests that genetic diversity will reduced at range margins, where population sizes will be small.

2. Collecting samples every 10 to 20 years may not be long enough for genetic adaptation to be manifested, particularly in perennial species, but equally may not be frequent enough to prevent severe genetic erosion under rapid climate change of annual species.

3. ‘Conditioning’ seeds at high temperature to allow for the selection of genotypes with temperature tolerance will have a seriously adverse effect on genetic diversity as a whole. Regenerating seeds from small numbers followed by their reintroduction will impose a severe genetic bottleneck. On the positive side, evaluating germplasm for adaptation to abiotic stress has certainly been encouraged for many years now by those scientists, genetic conservationists and plant breeders who continue to value and conserve those wild plant species that are relatives of crops.

4. Mixing seed samples to allow ‘cross-breeding’ and then allowing selection to act upon the genetic variation that results is not dissimilar to plant breeding. But is it not just as likely that outbreeding depression rather than the desired heterosis will result? There is a growing opinion amongst plant breeders anyway that conventional plant breeding is too slow a process to keep up with climate change. Also, is it feasible to consider ‘breeding’ is manner suggested all wild species before they are reintroduced to the wild.

5. ‘Conditioning’ and mixing seed sample then replanting them in the wild is likely to result in genetic pollution and potential diluting of local ecotypic adaptation. This has already been shown to occur in species with wild and cultivated components. The niche that any plant grows within is defined by a complex range of biotic and abiotic interactions and not all will be impacted by a changing climate.

6. But here’s the real conundrum, if seed banking (ex situ conservation) is currently inadequate, why not simply rely upon in situ conservation of wild plant species in genetic reserves? It would seem that the arguments that climate change will preclude such an approach in the near future applies equally to the suggestions made in this article.

In the final scheme of things, complementary approaches to the conservation of plant diversity, both ex situ and in situ, are important for that diversity to be used to its fullest, and not just for reintroduction alone. This needs strengthened support in the face of climate change, the scientific case for which has been argued for at least the last 20 years.