Category: Genetic diversity

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The Future of Plant Genetic Resources discussed in London

From our friend Ola Westengen.

Thanks to the announcement on this blog I learned that the Linnean Society were having a meeting entitled “The Future of Plant Genetic Resources.” When I saw the list of speakers a couple of names triggered me to search the dark corners of my budget, were I found just enough for a cheap return ticket to London. It was definitely worth the trip. I owe you a report, and I actually intended to write one up on the flight back, but the wine reception at the end of the meeting took its toll on my concentration.

So now, three days later, instead of decoding my notes from the many excellent talks, I’ll just direct you to the “Abstract book.” I wish I also could show you some of the great pictures in Sandra Knapp’s presentation, such as the one where Professor Jack Hawkes crosses an Andean river with the water waist high — still with his hat and tie on. Jack Hawkes definitely deserves his prominent place in the PGR pantheon, and his formative role for collecting, taxonomy, conservation and policy in this field was highlighted by several speakers. Quite a few, but not the majority, of the talks centered around the Solanum genus and the potatoes. The taxonomists are still arguing about splitting and lumping in the cultivated potato’s extended family, but no one disputes the important contribution made by Jack Hawkes, which still seems to serve as the baseline. Molecular markers are elusive stuff compared to the morphological characters recognized by the trained eye of an aficionado.

Actually, traditional molecular marker studies took a beating from more than one speaker, including by the new King of Corn, Ed Buckler, on some pretty breathtaking methods and results with implications for genetics that go far beyond that even the world’s most produced cereal. Did you know that two lines of maize are in average as divergent from each other as humans are from chimpanzees? Think about that the next time you eat popcorn at the zoo.

The Scottish Crop Research Institute was represented with three good talks, two on potatoes and one on an awesome barley landrace study done with ICARDA. The results will soon be published, and if you fancy beer and other barley products you should keep an eye on their website. PGR collectors, like few other scientists, can claim that their work lives on after they are gone. While Jack Hawkes’ legacy is indisputable, his potatoes are still flowering in the fields of the world’s genbanks. The Commonwealth Potato Collection sports a great website where these flowers can be seen online. Some of you will appreciate their use of Google Earth on their accession list. Check out the abstracts for more. Thanks to the Linnean Society for organizing this inspiring meeting and thanks to the Agricultural Biodiversity Weblog for making it known! At least to me.

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Ampelographical errors good and bad

It has recently emerged that some Australian vine growers have been growing Savagnin Blanc (Traminer), an obscure French variety from the Jura, rather than what they thought they had planted, the considerably sexier Spanish grape Albarino. Apparently, CSIRO was sent mis-labelled cuttings by the National Germplasm Collection of Spain, a mistake that was spotted only after DNA work. It’s all explained, with what I suspect is relish, in an article in the New Zealand Herald. ((The problem seems to have surfaced in the press back in April, but we missed it at the time.)) Just the latest in a long line of trans-Tasman wine spats.

For the Australian winegrowers that have planted the 150ha currently in production in the country, this discovery is a blow as while there’s demand for albarino, the profile of savagnin – which they must now label wines made from these vines – is considerably lower.

As the article points out, not all such errors in identification are bad news.

Over a decade ago in Chile, another case of confusion proved more fruitful when what the Chileans had previously considered merlot actually turned out to be carmenere. This “lost grape of Bordeaux” was virtually extinct until it was found alive and growing very well among the merlot in Chile. It was a situation that inadvertently preserved the variety and led to the New World wine-producing nation to embrace it as a real point of difference and claim it as its flagship variety.

DNA fingerprinting should put a stop to this, of course. But as there are “5000 wine grape varieties with over 20,000 different monikers,” at least according to the article, it may be a while until cases of vine mistaken identity are things of the past.

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Modern rice varieties (can sometimes) increase genetic diversity

ResearchBlogging.orgPeople 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.

Chhomrong village, at more than 2000 metres, was the source of one of the parents of the new varieties. Farmers have all sorts of techniques to grow rice at that altitude.
Chhomrong village, at more than 2000 metres, was the source of one of the parents of the new varieties. Farmers have all sorts of techniques to grow rice at that altitude. Photo: B. Sthapit

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.”

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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.