Tuesday, 1 April 2008


In our seedsavers group we are keen to save the seeds of those vegetables and fruits that will grow and produce well in our specific climatic and soil conditions. But where did these plants come from and what were they like before they were changed and domesticated by time and travel? Only relatively recently has any thought (and no money) been given to studying the amazing gene pool of edible plants native to Australia. We - human life - are lucky to have this untouched (ie unchanged) source of possible food crops 'up our sleeves' because most of the original wild plants from which our current seeds have come have been lost. What does this mean 'lost' ? Does it matter now or is this all just academic history? These are some of the questions that came up when I was talking about this with a friend recently and I would like to focus on them here.

Here is an excerpt taken from the introduction of an excellent and extensive report in a series on the arguments for protection of wild food sources and traditionally farmed areas.
Food Stores: Using Protected Areas to Secure Crop Genetic Diversity.
A research report by WWF, Equilibrium and the University of Birmingham, UK

..."The Green Revolution of the 1950s spread high yielding, disease and pest resistant new varieties across the developing world; by 1990 they covered half of all wheat lands and more than half of all rice lands – a total of some 115 million ha. As yields increased, the diversity of crops and varieties has decreased, reducing potential for adaptation to changing conditions. Today, it is widely stated that just nine crops (wheat, rice, maize, barley, sorghum/millet, potato, sweet potato/yam, sugar cane and soybean) account for over 75 per cent of the plant kingdom’s contribution to human dietary energy.

The Food and Agriculture Organisation of the United Nations (FAO) estimates that about 75 per cent of the genetic diversity of agricultural crops has been lost in the last century due to the widespread abandonment of genetically diverse traditional crops in favour of genetically uniform modern crop varieties. There are however still many millions of small farmers, particularly in marginal agricultural environments unsuitable for modern varieties, who practice traditional agriculture by cultivating community-bred crops (or ‘landraces’) produced through cycles of sowing, harvesting and selection of seed for planting over many generations. The genetic diversity represented in these landraces remains a vital resource for global food security and economic stability.

An equally threatened global agro-biodiverse resource is the reservoir of genetic diversity found in the wild species that are closely related to crops, the so-called crop wild relatives (CWR). Farmers have for millennia benefited from the natural crossing between crops and their wild relatives introgressing beneficial traits into the crop that enable it successfully to counter evolving pest and diseases andenvironmental changes. Contemporary breeders are increasingly searching the gene pool of crop relatives for these desirable traits.

Both landraces and CWR thus serve as the world’s repositories of crop genetic diversity and represent a vital source of genes that can ensure future food security. Their importance is increasing as human population growth and climate change alter environmental conditions and thus force the pace of agricultural change. This report reviews the importance, conservation and use of the genetic diversity found in CWR and landraces, and considers options for their conservation when associated with protected areas

Even if we only look at this topic from a human perspective (rather than including effects on other animals and other life) it can rapidly be seen that genetic diversity is of utmost importance if we are to maintain food production for our enormous population (and that is another topic for another day). Here is one sentence taken from the paper which gives a clear example:
.."During the 1970s, grassy-stunt virus severely reduced rice yields across Asia; after four years of research, during which over 17,000 cultivated and wild rice samples were screened, disease resistance was found in one population of Oryza nivara growing wild near Gonda in Uttar Pradesh, India. Resistant rice hybrids containing the wild Indian gene are now grown across Asia." If the habitat of this single wild rice had been destroyed then the virus may have meant starvation for many Asian people. Every time a single strain of any plant is lost, it may be costing thousands of lives because of its undiscovered attributes.

If humans continue to allow the constant erosion of the size of natural habitat areas, although that piece of habitat may continue to thrive in the short term, in the long term it means that the gene pool of every plant in the zone has been reduced. This ultimately results in an ever increasing number of plants species being unable to adapt to radical changes in conditions, such as may be the case with climate change, simply due to a lack of genetic diversity. Therefore, when we need to draw on the wild genes of the ancestors of our food crops, in order to fast-track some adaptation to climate change, we will not be able to find any wild species with the necessary genes either. This is a serious possibility for the crops of the greater part of the world. Inevitably this may lead to an acceptance of GM technology as the only solution. In other words we may be forced to get the genes from other species - plant or animal.

Similarly, farmers have helped to enrich the gene pool of crops by sowing, harvesting and saving proportions of seed for subsequent sowing. For example, in Ethiopia, local varieties grown using animal manure as opposed to chemical fertilisers tolerate moisture stress and resist disease and pest infestation better than varieties sold to farmers as 'improved'. These locally-bred crops need to be preserved ...."Communities that lose locally-bred varieties (landraces) and knowledge of how to grow them, risk losing control of their farming systems and becoming dependent on outside sources of seeds and the inputs needed to grow and protect them. In turn, this can lead to the additional risk that during periods of economic downturn they may no longer be able to afford the chemical inputs that are essential to grow the new varieties. Loss of traditional varieties thus has important implications for social equity and for the ability of impoverished communities to survive periods of drought or other atypical conditions."

The power to feed themselves is being taken away from the traditional farmers of the third world as well as from the citizens of the so-called first world and this is leading to the disintegration of the social fabric of many communities. This is just an introduction to some of the topics covered by this paper.

It is only through the maintenance of the genetic diversity of wild food plants and landraces in every nation on earth that there can be any attempt at successfully working our way through the changes that appear to be mounting up in front of us to produce natural, healthy food into the millenia ahead.

1 comment:

Greg W said...

Kate, this sounds pretty dire.

While developing the high yield, disease and pest resistant varieties that allowed our population to increase we are actually creating a situation that could cause it to fall.

It is possible that a new naturally created variety will be produced from crossing wild plants with what we have created through GM and that the resultant crop could fight off the next pestilence attack.

We can only hope we come to our senses and stop spreading out into the only natural habitats we have left.