Signs of a cassava field have been found under the several metres of ash that buried a Mayan village when a nearby volcano erupted in about 590 AD. Archaeologists excavating Ceren in San Salvador — dubbed the American Pompeii — found tubular hollows in the solidified ash, formed when the tubers decomposed. This is apparently the earliest evidence of cassava cultivation.
Backyard domestication
There’s a “dump heap” hypothesis of agricultural origins which suggests that people first got interested in actively managing and manipulating plants for food or other products when they saw them sprouting out of piles of garbage in and about settlements. There they could observe them daily and experiment with them. A slight variation on this theme — involving corrals in pastoralist campsites rather than garbage dumps — has been proposed for the domestication of quinoa.
One of the things that might have happened in these fertile micro-environments in close proximity to human habitations is that different related species might have been brought accidentally together, leading to hybridization and the development of interesting new — polyploid — types. But there really hasn’t been much empirical evidence for this.
No more. A new paper ((Colin E. Hughes, Rajanikanth Govindarajulu, Ashley Robertson, Denis L. Filer, Stephen A. Harris, and C. Donovan Bailey. Serendipitous backyard hybridization and the origin of crops. PNAS published August 17, 2007, 10.1073/pnas.0702193104.)) looks at the domestication of the legume tree Leucaena in Mexico, where it is grown for food (it is also used as a fodder in some parts of the world). A variety of evidence is discussed which suggests that there has indeed been much hybridization among up to 13 different wild species of Leucaena in Mexican backyards. This has proved “a potent trigger for domestication.” The authors think a similar thing also happened in Mexico with two other perennial crops, Agave and Opuntia.
Mapping wild bovids
Michael’s post on the kouprey made me realize how ignorant I am on the subject of wild bovids. That, and news of the launch of the new GBIF portal, prompted some online fun and games last night.
I’ll just give you the edited highlights here. But I guarantee that playing with the GBIF data portal will keep you busy — and entertained — for hours.
I searched for all Bos spp specimens that GBIF has occurrence data for, then downloaded the resulting kml file and opened it in Google Earth. The map above is just a view of the records for SE Asia. Not that many, and none for the kouprey. Bos javanicus is the banteng. The records in southern Vietnam refer to specimens (stuffed, presumably, or maybe just skins, I’m not sure) from the Field Museum in Chicago.
I got quite excited when I saw the name of the collector. One T. Roosevelt. But it was not to be. This T. Roosevelt collected (shot?) the banteng specimen now in the Field Museum in 1929, which is ten years after the first President Roosevelt died.
I also did similar things for a couple of crop wild relatives, but I’ll keep that for another time. Remember, one of the data providers to GBIF is SINGER, to the tune of over half a million records of germplasm accessions of crops and wild crop relatives.
Later that day: So GBIF has a thing where you can send feedback on individual records, so I did that for T. Roosevelt’s banteng and within a few hours I had a email back from Larry Heaney at the Field Museum. It turns out that we’re dealing here with Teddy Jr, the president’s son, who spent a lot of time on expeditions in Asia. Larry says that there are also some specimens around collected by Teddy Jr’s brother, Kermit. Thanks, Larry. I don’t know quite why, but this whole story made my day.
Archaeology of chili peppers
Remains of oldest Mexican takeaway found.
The geography of rice
Robert Hijmans has a great new global map of rice cultivation out. Robert is at IRRI now, hence his current preoccupation with rice, but he’s done the same thing for several other crops, and of course there are his cool cartograms too. I guess it is his map that underlies the figures of the potential impact of climate change.
Of course, this is a snapshot. How cultivation of a crop changes over time is difficult to capture in a single image, but there’s a map which does a pretty good job for maize.