Domestication trifecta

We’ve blogged a number of times about the paradigm shift that’s occurring among students of plant domestication, driven by increasing interaction and synergy between archaeologists and geneticists. The idea of “rapid, localised” domestication is down if not out: all the talk these days is of domestication as a protracted, multi-locational and biologically complex process.

Well, there’s a very nice review of the history of this shift in Trends in Ecology and Evolution, at least as it concerns the crops domesticated in the Fertile Crescent. It is only very recently that geneticists have looked at their molecular data in the light of archaeological results and realized that there were other ways to interpret them apart from the conventional idea of domestication in one place over the course of a few human generations.

Meanwhile, a paper in Annals of Botany looks at another source of data, i.e. written sources. Chinese investigators have looked at references to eggplants in ancient encyclopedias, concordances and even poetry, and charted changes in size, shape and taste over the past 2000 years. The oldest reference dates back to 59 BC, and since then the Chinese eggplant has gone from round to a variety of shapes, has increased dramatically in size, and has become much sweeter.

Finally, our friend Hannes Dempewolf and co-authors have a paper in GRACE which looks in detail at domestication in the Compositae. Why have only a handful of species in this family been fully domesticated? Secondary defence compounds, inulin as a storage product and wind dispersal, the authors suggest.

Nibbles: Early diet, Rice, Veggies, Barley, Research, Taiwan, Coffee trade

Go forth and grow halophytes

That seems to be the plea Jelte Rozema and Timothy Flowers make in a Science paper that’s just out. ((It’s behind a paywall, but you can read other people’s take on it at Mongabay and Wired.)) But, frankly, I found the paper disappointing, not least because it is short on clear recommendations. For example, what is one to make of this?

Because salt resistance has already evolved in halophytes, domestication of these plants is an approach that should be considered. However, as occurred with traditional crops such as rice, wheat, corn, and potatoes, domestication of wild halophytic plant species is needed to convert them into viable crops with high yields. Such a process can begin by screening collections for the most productive genotypes.

Are they telling us that domestication of new species is a more profitable approach than trying to breed salinity-tolerance into existing crops? I think so, in which case it would be an interesting view, but I’m not altogether sure that’s in fact the point they’re making. It could have been better phrased. I mean those first two sentences could be summarized as

Domestication of halophytes should be considered. However, domestication of wild halophytes is needed.

Not sure how the editors at Science let that one by. There was also no explicit reference in the paper to the International Centre for Biosaline Agriculture and its genebank. Or to the possible role of crop wild relatives in breeding for salinity tolerance. All around, an opportunity missed.

Nibbles: Wikiforéts, Super-rape, Gut microbiome, Soybeans, Golf courses, Chestnuts, Rice, Yeast

Cocoa from tree to cup

News from both ends of the cacao value chain today. At the upstream end, new molecular marker work on over a thousand genebank accessions reveals that the species is divided into no less than 10 genetic clusters, rather than the conventionally recognized two. These show a clear geographic pattern: they are strung out along an east-west axis in the Amazon, probably reflecting, according to the authors, the location of ancient ridges (“palaeoarches”), which were barriers to dispersal not only for Theobroma but also for various fish groups. Meanwhile, at the downstream end, there’s an account of a visit to a “chocoholic mecca” in Santa Fe.

LATER. And, for the trifecta, news from somewhere around the middle of the value chain.

LATER STILL. What comes after trifecta?