Horticulture and Agriculture

16 Mar 2010

There is another consensus model under attack. This time the oft repeated claim that plant cultivation made a sudden appearance in the Near East around 10,000 years ago and spread rapidly into Anatolia, the Balkans, through the Mediterranean and across central Europe (in one direction) and into the Indian sub-continent in the other. The spread of farmers into these regions is often integrated with the theory of the spread of language - in both directions. It also affects the way that human genes are being interpreted - in Europe for example. The problem has always been that archaeologists and biologists have only been looking at the Holocene - as the Pleistocene and the Palaeolithic are largely invisible, buried beneath the ground. Now, a mathematical study by researchers at the University of Warwick, led by Robin Allaby, have shown that useful gene types (of plants) could have taken thousands of years to stabilise. The old model relied on artificial selection in order to dominate natural plant selection and crucially to the theory it relied on the idea that specific crops developed in a single region. In China and the far east it was rice, in the Americas it was maize, in Africa it was sorghum, and in the Fertile Crescent it was wheat and barley. Hence, it relies on a single domestication event - possibly down to a single family or small community. This theory developed out of modern plant selection, I suppose, as new hybrids can emerge fairly quickly. However, recent archaeology has undermined the nature of this 'agricultural revolution' model so beloved of historians in their descriptions of human societal development, as the beginnings of plant cultivation are much earlier than imagined. The Neolithic revolution owed some of it's origins to evolutionary ideas prevalent in the late 19th and early 20th centuries - society developed from a primitive to an advanced state by a series of well defined phases that was the equivalent of brute to modern civilised and schooled chaps and young missies. Some intimation the model was not quite as robust as imagined has been apparent for some years as on New Guinea so called hunter-gatherer populations were living in a fairly densely populated landscape by reason they did not solely rely on the local environment for their food - but practised village horticulture. It has emerged that horticulture may have been practised even as early as the Middle Palaeolithic. Reproducing a plant by sticking a branch or piece of stem into the ground could have been practised for generations before the Neolithic era. In any case, early Neolithic sites in the Fertile Crescent are often found in association with favoured trees (the provide a crop) - such as nuts and fruits (from pistachios to figs).

At a site in Syria there is a wealth of evidence over 23,000 years that seem to show wild cereals were being gathered in the Palaeolithic era - pong before the advent of the Holocene and the beginnings of agriculture. This was contemporary with the last Glacial Maximum when temperatures on the whole earth are supposed to have been extremely cool and inhospitable. Various studies have shown that domesticated species of crops occurred in a fairly slow sequence - plant traits emerging individually rather than at multiple stages. Using computer simulation it has been shown that cultivated crop types settle into a stable reproducable variant at a rate proportional to it's population size as compared to gene variations in the wild. However, as we are talking about computer simulation it is worth noting what was not part of the programme fed into the machine - catastrophism. Rapid biological change at random points in the past is also a fact.

At http://www.npv.org id5446137 September 13th 2008, the discovery of figs near the ancient city of Jericho, and dated at 9500BC (the very beginning of the Holocene) led to the idea the much prized fruits may have been cultivated long before cereal grains. In addition, the figs were mutants - they could not reproduce unless somebody took a cutting and planted it.

Wild fig trees would have been encountered and enjoyed but if people had moved on they may have wanted to take such a plant with them. At some stage somebody snapped off a stem and tried planting it - and it rooted. Figs were spread by cuttings - and still are. The Jericho evidence suggest that by 9500BC figs were already domesticated - and this would have taken a significant period of time to achieve the change from wild to mutant.

A similar argument has been made about chick peas. This crop is notoriously difficult to grow and may have been domesticated before cereal grains once again as it has a rare attribute - it leaves a feeling of fullness, and may have been seen as beneficial and desirable even to hunter gatherer communities.