You may remember an earlier – somewhat facetious – post on a possible threat to tea diversity in China. Now, from CropBiotech Update, there’s a summary of a far from facetious review paper on tea breeding in that country. Turns out that the China National Germplasm Tea Repositories can count on some 3000 tea germplasm accessions, and that over 200 improved varieties have been released. Some quite advanced biotechnological approaches are being used to speed up breeding. One of the things the researchers are looking at is developing cultivars with low or no caffeine, using RNAi. Personally, I think caffeine-free tea and coffee, like alcohol-free beer, are a bit like a one-legged man at a butt-kicking contest: useless. But the technology is cool.
SciDev.net reports on a paper in Theoretical and Applied Genetics that identifies the world’s most genetically diverse barley varieties. SciDev.net and other press reports focus on the high diversity of the barleys, found growing in farmers’ fields around the captial city of Asmara in Eritrea, as a source of potentially valuable material for improving tropical varieties worldwide. They point out, too, that the populations are threatened by urban development and that Eritrea has no genebank in which to protect them. But does Eritrea really need its own genebank, or have they more pressing priorities? A researcher from ICARDA, which has a perfectly serviceable genebank, was on the team. The International Treaty on Plant Genetic Resources for Food and Agriculture guarantees free access to the material if stored there. Eritrea was one of the first signatories of the Treaty. What’s the problem?
More interesting, perhaps, is a part of the paper that the reports I read neglected to mention. The molecular analysis indicates that the Horn of Africa may be where barley was first domesticated. That honour usually goes to the Fertile Crescent, with the Horn a “secondary centre of diversity”. But Eritrean and Ethiopian barley may actually have been domesticated independently.
There was a slightly odd article at Seed Magazine a little while back on Thailand’s efforts to conserve almost extinct varieties of rice in its genebank. Odd because while the story is familiar enough in this kind of piece, the details are slightly confused (or confusing). But no matter, that’s probably only of concern to a pedant like me. The rest of you won’t worry about statements like “farmers across Asia once grew more than 100 varieties of rice, but now that number is down to only 20 or 30 of the most productive types”. Instead, you’ll be thrilled to know that the Thai national collection houses nearly 24,000 varieties, 17,000 of which “are in danger of dying out because they are no longer grown by Thai farmers”. That’s great because SINGER, a window on the world of genebank accessions, lists only 5982 samples from Thailand. Maybe one of those is “the fragrant Pin Kaew variety that was named the best rice in the world at a competition in 1966 but which has since disappeared, having lost out to more productive varieties”.
Are crop wild relatives (CWR) more trouble than they’re worth? There are certainly significant challenges involved in including them in breeding programmes, but you’d have thought that between the new molecular tools that are now out there, the greater numbers of CWR accessions in genebanks, and all the information about how useful CWRs can be, breeders would be falling over themselves to make those kinky inter-specific crosses. Well, according to a major review by our friends at Bioversity International (the outfit formerly known as the International Plant Genetic Resources Institute), the use of CWRs in breeding programmes has been steadily increasing in the past 20 years, but probably not as much as might have been expected. There’s been a number of papers recently on CWRs. This paper, also from Bioversity, looks at in situ conservation of CWR. Check out this for a discussion on the definition of the term, and, from some of the same people, there’s this overview of conservation and use of CWR, using a specific example. Here’s an example of conservation assessment and priority-setting for the wild relatives of the peanut. For a discussion of the possible effects of climate change on these species, see this.
Researchers have estimated rates of reproduction and survival for the marbled murrelet by “comparing the ratios of birds in different age groups using 170 specimens collected between 1892 and 1922 housed in the collections of the California Academy of Sciences and the UC Berkeley Museum of Vertebrate Zoology … with values predicted from comparison with other bird species, and with contemporary rates obtained from murrelets they captured at sea and from their mark-recapture studies.” The results suggested that birth rates were almost 10 times higher for this endangered seabird 100 years ago than they are today. Read all about it here. That’s a very creative use of a biodiversity collection to explain the recent decline in numbers of this species, and its conservation status. Has something similar been done with herbarium and/or plant genebank collections? I can’t think of any examples, but they must be out there…