- Global seed searcher Adam Forbes check in.
- Filipinos greet new squashes.
- Smithsonian special feature on the American Indian. Not much agrobiodiversity, but still.
- Reviews of a couple of interesting gardening books.
- Asian Buffalo Congress 2009.
- Policies that work for pastoral environments.
- “Farmers are being encouraged to graze fewer, rarer animals, and that means the fields can sustain traditional wild flowers. It is a sweet-smelling plant and cattle and sheep love to eat it.” It is the cowslip.
- Case studies on intellectual property in agriculture and forestry.
Modern rice varieties (can sometimes) increase genetic diversity
People say that introducing high-yielding crop varieties threatens agricultural biodiversity. Farmers adopt the modern varieties and abandon their traditional varieties, so that the overall genetic diversity falls as a result. They’re right, but not every time. A new paper published online in Field Crops Research ((Steele, K., Gyawali, S., Joshi, K., Shrestha, P., Sthapit, B., & Witcombe, J. (2009). Has the introduction of modern rice varieties changed rice genetic diversity in a high-altitude region of Nepal? Field Crops Research DOI: 10.1016/j.fcr.2009.04.002)) shows that genetic erosion need not be the unintended consequence of high-yielding varieties, especially if the modern varieties count farmer varieties among their parents.
In the early 1990s, while a PhD student at Bangor University in the UK, our friend Bhuwon Sthapit, now a senior scientist at Bioversity International, was instrumental in breeding three new varieties of rice suitable for upland rice farms in Nepal. This was no ordinary breeding programme, however. Sthapit worked closely with farmers, who both set the goals of the breeding programme and participated in the selection of the final varieties from the many crosses. The varieties were selected from crosses of Chhomrong Dhan, a local landrace well adapted to the cold conditions of high-altitude rice farms in Nepal, with Fuji 102 and IR36, more productive material from international breeding programmes.
Farmers selected three lines: Machhapuchhre-3 (M3), Machhapuchhre-9 (M9, which is similar to M3 but with lower cold tolerance) and Lumle-2 (L2, like M3 with better grain quality and easier threshing). Only M3 was officially released, but M9 and L2 have been adopted widely thanks to informal seed exchanges among farmers. By 2004 about 60% of the land in the study villages was sown to one of the three COB (client-oriented breeding) varieties, while traditional varieties occupied the remaining 40%. In adopting the COB varieties, many farmers had dropped traditional landraces, but there was no clear pattern to which landraces were dropped in which villages. The variety dropped most commonly was Chhomrong Dhan, one parent of all three COB varieties.
To assess genetic diversity, Sthapit and an international team of the researchers from Bangor and Nepal analyzed DNA from the three COB varieties, a random selection of landraces and a control group of modern varieties. Overall, genetic diversity was greatest in the landraces, and least in the COB varieties. However, there was no loss of genetic diversity across the district as a whole, at least as long as the three COB varieties were adopted on less than about 65% of the land. Indeed, because the high-yielding parental varieties contribute alleles not previously known in the area, there is an increase in diversity as the COB varieties are adopted .
Another crucial result is that although some farmers grow COB varieties on 100% of their land, nevertheless, at least 11 diverse landraces survived on some 40% of the land. These landraces clearly meet needs not fulfilled by the COB varieties. For example, although the most commonly dropped variety was Chhomrong Dhan, farmers in the Gurung community continued to grow that variety.
“It is the preferred rice for preparation of the dish Madeko Bhat used during funerals and other ritual and social ceremonies,” Sthapit told us.
“The conclusion is clear,” Sthapit added. “Participatory breeding and client-oriented breeding programmes should choose locally adapted varieties as parents for breeding. It ensures that landrace genes are conserved and increases the likelihood that the breeding programme will succeed.”
Diversity on air
I’ve been listening to a radio programme about diversity in action. Called The Evolution Boomerang, from Soundprint, it examines three cases where diversity is important to agriculture and the environment. There’s a segment on GMO cotton and insect resistance, a segment on the need for genetic diversity at salmon hatcheries, and a segment on selecting bacteria to degrade a chemical that had never existed on Earth before humans manufactured it.
All good stuff, if you have half an hour to spare. You will need Real Player to listen.
The giant pumpkin story
Jules Janick, professor of horticulture at Purdue, wrote a wonderfully informative and entertaining brief history of giant pumpkins in last September’s Chronica Horticulturae (it starts on page 16). Regular competitions have been going on in the US since 1900, arising from state agricultural fairs.
The giant round orange phenotypes of C. maxima appear to be in a narrow gene pool out of “Atlantic Giant” (oblong phenotypes are called “Dill’s Atlantic Giant” developed by William Dill, a Canadian from Nova Scotia, Canada)… “Atlantic Giant” and related huge show pumpkins trace their origin to the cultivar “Mammoth,” recorded in the seed trade as far back as 1834…
Despite this narrow genepool, the genetic gains have been phenomenal (although of course cultural practices play a part too), as this graph of world records of pumpkin fruit weight from 1857 to 2007 shows:
The current mark stands at almost 800 kg. Seed of top specimens changes hands at huge prices (up to $850 for a single seed). Prof. Janick suggests that horticultural science has ignored this record of success.
Someone has accused academics in the agricultural arena of merely proving that the practices achieved by the best growers are correct. I suggest the academic and scientific community cooperate on this engaging problem for the delight of the public everywhere.
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?