Romaine, the oldest lettuce…
More potato salad
Never rains but it pours, part 37. Local newspaper article on the US potato genebank.
Potato salad
I don’t know if it’s because of the International Year of the Potato, but there’s been a fair amount on the spud in the news lately. I nibbled a few days ago news of a paper which will cause a major rethink on the worldwide spread of the potato. Virtually all modern potato varieties are derived from landraces from the lowlands of southern and central Chile. Why? Some people think it’s because those are the first ones that arrived in Europe. Others that there were also highland Andean varieties in Europe, but that they got wiped out by late blight. But analyzing DNA from old herbarium specimens shows that both types of potatoes were grown in Europe both before and after late blight hit. So a new theory is needed.
Then there was a short piece on the CIP collection in LatinAmericaPress. Note the cool picture of diversity in the colour of potato flesh. I’m not sure what prompted the article, but it may have been a CGIAR press release on how the international centres, including CIP, are sending germplasm for safety duplication in Svalbard in time for the opening in three weeks’ time.
CIP was also in the news with the announcement of the establishment of Red Latinpapa. That’s the Latin American Network for Innovation on Potato Improvement and Dissemination. Its “aim is to help poor potato farmers in Latin America improve their income and reduce costs by making it easier for them to access new technologies and varieties and getting their input into what traits are most useful.” Among other things, “Latinpapa will stimulate exchange and analysis of genetic material between researchers in the region.” A busy time ahead for the CIP genebank, and national genebanks around the region, I guess.
And finally, a bit of fun. Remember the picture of sliced potatoes in the LatinAmericaPress article showing lots of different colours and patterns? Of course, because of the relatively narrow base of modern potato varieties, as described in that USDA paper I started with, we don’t get potato chips (crisps for the Brits among us) in all these different colours. Bummer.
But maybe we will soon. Someone in Switzerland is indeed working on a blue chip. But in fact mixtures of blue and white chips are already commercially available in the US. Although they “have a weird flavor that is not quite potato.” Sounds intriguing…
Hot cocoa
The Fairtrade Foundation licenses this special mark to distinguish products that have been certified as meeting certain producer and trading standards, meant to ensure that small-scale producers and plantation workers in the developing world get a better deal. The producers “receive a minimum price that covers the cost of sustainable production and an extra premium that is invested in social or economic development projects.” And farmers are thus given an incentive to maintain agrobiodiversity on farm. However, as an article in last week’s Economist points out, this model is not particularly popular among the large corporations that control the global trade in agricultural commodities: “Fairtrade’s price-adjustment mechanism is intended to insulate small producers from volatile commodity markets and the free-trading, no-holds-barred capitalism that multinational companies espouse.”
And yet, Fairtrade-like strategies — The Economist calls them “Fairtrade lite” — are increasingly popular: “firms are finding ways to improve the lot of small farmers, and burnish their own reputations, without signing up to Fairtrade’s rules.” The article describes the latest example.
It is called the “Cadbury Cocoa Partership,” and it commits that multinational to investing US$87 million over 10 years in increasing cacao yields in Ghana. That country provides Cadbury Shweppes with 70% of its global needs (100% of its UK needs), amounting to 10% of Ghana’s production. A recent study showed that yields have been decreasing and youngsters leaving the farms, imperilling supply. Cadbury does use a Fairtrade-certified cocoa (from Belize), but in this case it decided that the problem was not so much price as productivity, and came up with its own scheme.
Intercropping will be encouraged (peppers, mangoes, coconuts) as an additional income option, wells dug to free up the time of women and girls, and schools and libraries built, equipped and staffed. But it is unclear how productivity is to be increased. The article says that “the aim of the venture is to show cocoa farmers how to increase yields using fertilisers and by working with each other.” Surely that’s not going to be enough. Hopefully cacao genetic resources conservation, evaluation and breeding work will also be supported. ((There’s a good summary of the importance of diversity in a New Agriculturalist focus feature on cacao, but it is from a few years back.))
Soybeans and its bottlenecks (or lack of them)
All too often crop genetic diversity studies — even ones published in peer-reviewed journals –Â are not really testing a clearly set out hypothesis. Markers are chosen and scored for each accession in a germplasm collection, and that’s basically it. Oh sure, estimates of various genetic parameters for the collection as a whole are provided, and there are dendrograms aplenty to illustrate the relationships among accessions. Which is fine, that sort of information can be useful. But one sometimes wishes that more focused questions had been asked — and answered.
Which is why recent work on soybean from USDA and visiting scientists from China and Korea is so interesting. I saw it reported in the February issue of Biodiesel magazine, but the original news item goes back to late last year. What the USDA team did is not just fingerprint material from the 17,000-strong USDA Soybean Germplasm Collection maintained at Urbana, Illinois and publish a nice dendrogram showing how Chinese accessions are related among themselves and to Korean ones, for example. ((Although someone probably did that as well!)) They defined four distinct sets of germplasm, each of which was derived from the one before, and tested the specific hypothesis that each process of derivation caused significant narrowing of genetic diversity, i.e. was associated with a “genetic bottleneck.” The sets of material were:
- 26 accessions of wild soybeansÂ
- 52 Asian landraces derived from them
- the 17 Asian landraces introduced to the US in the 20th century
- 25 elite modern cultivars which have been bred from them
What they found is that genetic diversity (as measured by gene sequencing) in wild soybeans was much greater than in landraces, which is fair enough. Most crops go through a very strong genetic bottleneck at domestication. What was more surprising is that the loss of genetic diversity caused by the introduction of only a few landraces to North America, followed by intensive breeding, amounted to only about 25%. This was much less than expected. The genetic base of US soybeans is narrow, yes, but not that narrow, it turns out.
What this means is that randomly introducing more landraces into soybean breeding programmes will not be very effective. The authors suggest that landraces should instead be carefully selected from the Urbana collection based on what the specific breeding objectives are at any one time. So, if breeding for resistance to the Asian aphid is the aim, landraces from areas of Asia where this pest is found should be the ones to be thawed out of genebank and crossed with the elite material.
All very logical. But I wonder. Was all that gene sequencing really necessary to reach this conclusion? I mean, wouldn’t you want to be somewhat selective in the landraces you introduce into a breeding programme even if the genetic base of the crop had been narrower? Maybe a breeder will help me out here. But anyway, it was good to see a real hypothesis of practical significance clearly set out and tested through specific comparisons in a crop molecular diversity study.