The latest edition of IITA’s R4D Review has various articles on agrobiodiversity issues, including a roundup of the activities of the centre’s genebank and an interview with its manager, Dr Dominique Dumet.
Battling it out over drought-tolerant maize in Africa
Maize in Africa is becoming a bit of a battlefield in the agri-culture wars. The BBC has a radio programme on the Water Efficient Maize for Africa project, which is a partnership between national programmes, CIMMYT and Monsanto, with a lot of work being done in Kenya. Predictably, it is very biotechnology-oriented, with marker-assisted selection and genetic modification to the fore.
At the other end of the spectrum, Scientific American has an article on a GEF project (funding comes also from Norway and the Netherlands) at Sakai, Kenya which is very different.
Agricultural extension officers now offer seasonal and locally relevant climate predictions explained in simple terms in Kikamba, the regional tribal language. They are now producing a handbook to translate weather predictions into practical advice about what and when to plant.
The project has also helped farmers set up a seed bank. A group of about 40 men will collect, process and preserve the best local seeds and loan them out again during the next planting season, slowly selecting for the best climate-adapted varieties.
Sakai’s farmers are hedging their bets. Increasingly, they are diversifying their crops by planting more drought-tolerant grains, peas and beans.
One wonders whether the two projects are even aware of each other, let alone talking. Maybe someone will tell us.
Evaluating St John’s wort not as easy as it sounds
USDA researchers at Ames, Iowa are screening 180 accessions of St Johns wort (Hypericum) for biologically active compounds. I hope they’ll take into account phase of the moon in their evaluations:
Research on St. John’s wort (Hypericum perforatum, Hypericaceae) herb, one of the top ten herbal products in retail sales in the United States, has shown seasonal variation and differences due to cultivation location. Levels of hypericin and pseudohypericin, the compounds to which commercial products are usually standardized, were found to vary from 100 ppm to 5000 ppm from winter to summer. This remarkable quantitative difference in compounds could account for some of the differences in commercial products whose raw materials are usually from multiple sources. Additional studies with St. John’s wort found significant variation among wild and cultivated plants sourced from around the world.
Nibbles: Interactive key, Cider tax, Drought screening, Egyptian genebank, USDA animal conservation, Homegardens, Bag farms, Soil movie, Breeding Vigna, Cereals yield gap,
- Got a Neotropical flowering plant to identify? Kew has what you need.
- New Labour goes out with a whimper, and a swipe at cider-makers.
- Drought Timing for Agronomic Screening wins a prize.
- “We’ve heard about the Gene Bank project which serves to preserve certain cultivars and seed specimens, but we don’t know much else about this project.” Par for the course.
- Meanwhile, another genebank does get decent publicity.
- Women and homegardens in Bangladesh.
- Bag farms in Nairobi slum.
- Review of Dirt! The Movie.
- Boffins this close to drought-tolerant cowpeas.
- “…actual grain yield in some regions is already approximating its maximum possible yields while other regions show large yield gaps and therefore tentative larger potential for intensification.”
- The wife is going to the 1st International Symposium on Tropical Horticulture. Jamaica? No, she really wanted to go.
More on future-proofing germplasm collections
A reply to Walck & Dixon from Brian Forde-Lloyd, Nigel Maxted and Luigi Guarino.
In 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.