- Liguria’s asparago violetto gets Slow Food treatment.
- “The bottom line is we just don’t know why they are struggling so badly.”
- Using mobile phones to treat plant pests and diseases in Uganda.
- Dingoes have positive effect on biodiversity.
- Date palm genome mapped.
- Boffins see the light, explain negative effect of fertilizers on biodiversity.
- Brogdale situation “better,” but for how long?
- Wait, Bern has a bear-pit?
Nibbles: Peppers, Medicinals, NYC gardening, Science writing, Urban ag, Pouteria
- Hot chili peppers on a blistering night, dust on my face and my cape…
- “North America’s only medicinal herbs germplasm collection.” New one on me.
- “Brooklyn was a breadbasket for the city only until the middle of the nineteenth century.” New one on me.
- Different journalistic takes on cow genome.
- Edmonton learns from Havana.
- Lucuma no longer novel, can enter Europe.
GMO bananas or nothing?
Simplicity rules, not only in the minds of many researchers and farmers, but also, and to an even greater extent, in the press. Shades of grey, subtleties of interpretation, multiple responses to complex questions; this is not the stuff of daily journalism. But why not? Is there any evidence that readers really can’t cope with this kind of complexity? Or maybe it is the journalists who can’t cope.
There’s no other way to explain the appearance, yet again, of a story saying that genetically engineered bananas are the best way to contain banana Xanthomonas wilt (BXW) in East Africa. According to the article, “genetic modification offers a low-cost and timely solution to the farmers who are reluctant to use labor-intensive control measures”. Those labour-intensive methods?
A task force set up by the Ugandan government in 2001 in response to the outbreak of the disease reduced the disease incidence to less than 10% in areas where farmers adopted these measures. However, the implementation is not sustainable due to the high costs.
But I can’t see any reference to studies of those costs, which could be reduced even further if new methods for dealing with infected plants become widespread. It seems to me that the projected losses in Uganda ascribed to BXW — between USD 2 and 8 billion over the past 10 years, and projected future losses of up to 53% “if the disease is left unchecked” — are intended to push the country towards genetic engineering as the only effective response. There is a place for GMO bananas, as part of an overall approach that uses a diversity of methods and a diversity of varieties to tackle not just BXW but all the other constraints on production of bananas and plantains in East Africa.
“GM bananas can wait,” a letter to editor of SciDev.net by our friends at the International Network for the Improvement of Banana and Plantain as was, is as relevant now as it was 2 1/2 years ago. One extract:
Biotechnology is one tool among many. Banana farmers should not be scared into accepting GM bananas as the only solution to a problem for which other measures are proving effective, and which Uganda’s National Agricultural Research Organisation is also actively promoting, in addition to its work on GM bananas.
Now, how hard is that to explain?
How to rescue a sunflower wild relative
A paper by Jennifer R. Ellis and David E. McCauley of Vanderbilt University, just out in Biological Conservation, tries to answer a couple of quite controversial questions for conservationists: ((Ellis, J., & McCauley, D. (2009). Phenotypic differentiation in fitness related traits between populations of an extremely rare sunflower: Conservation management of isolated populations. Biological Conservation. DOI: 10.1016/j.biocon.2009.03.029)) How do you prioritize populations for conservation? And when does genetic pollution become genetic rescue? Both answers depend on something most gene-jockeys don’t do much of: growing plants and seeing how they perform.
To add piquancy, the paper deals with a crop wild relative, and a very rare one at that: Helianthus verticillatus, which is known from only four sites in the southeastern United States. The authors worked on populations from two of these, in Tennessee (fewer than 100 individuals) and Alabama (several hundred individuals). They collected seeds from sixteen of what they had previously identified as genetically distinct individuals from each population, and then made a whole bunch of crosses, both within populations and also between the two populations, for two generations. They grew the progeny of these crosses in the same environment and measured how well they did in terms of fruit viability, germination, survival and pollen quality.
So, first, to the prioritization question. Genetic markers are now routinely used to identify populations that are particularly low in diversity and thus in need of immediate in situ protection or collecting for ex situ conservation. Often, genetic diversity is positively correlated with fitness, but this is not always the case. For H. verticillatus, in fact, it was known from previous marker studies that the two populations had comparable levels of genetic diversity and only moderate genetic differentiation. However, the results of the common environment study on the offspring of the intra-population crosses showed that they different significantly in their overall “fitness,” with the Tennessee material having lower germination rates and fruit viability. In other words, molecular markers on their own would not have raised a particular concern about the long-term viability of the Tennessee population. In the words of the authors, “contrary to genetic marker information, these populations are not interchangeable with regard to quantitative fitness characters.”
Next, the genetic rescue question. The conventional wisdom of course is that conservation should strive to maintain the genetic integrity of populations. Bringing in material from elsewhere constitutes genetic pollution and is BAD. The introduction of new genetic material into relatively homogeneous populations with low fitness can of course result in heterosis and increased fitness. But it can also lead to lower fitness — inoutbreeding depression — “owing to the dilution of local adaptations or disruption of co-adapted gene combinations.” Enter the inter-population crosses. Crossing Tennessee individuals with those from Alabama resulted in offspring that were more fit, with no sign of outbreeding depression, at least for the two generations of the study. This “offers great promise” as an active conservation strategy for the Tennessee population, the authors say.
Given people’s sqeamishness about messing around with rare species, I wonder if such activism will be given a chance.
Nibbles: Sheep, Yams, Satellites, Payment for ecosystem services, Museum
- Domesticated sheep spread in two waves.
- How IITA helps yam farmers in West Africa.
- “…it is vital that we develop some sort of early warning system that will enable us to take timely action if we see part of the landscape suffering and signs of the loss of species richness.”
- First issue of newsletter on Agricultural Payments for Ecosystem Services online at Ecoagriculture Partners.
- Visit Cairo’s Agricultural Museum. If you think you can take it.