| Evolutionary plant breeding within organic and agroecological farming systems is a better way to respond to the challenges of climate change than GM and other intensive farming methods, researchers from Italy show in two new open-access scientific reviews.
In evolutionary plant breeding, crop populations with a high level of genetic diversity are deliberately subjected to the forces of natural selection (stresses like extreme weather conditions and pests). The most successful plants are incorporated into the breeding programme. Crop populations developed in this way start out better adapted to the local conditions for which they are intended – and continue to evolve in the field, as conditions change.
Genetic variation is key
The first of the new reviews shows that evolutionary plant breeding can address the complexities of climate change while stabilising yields and decreasing agrochemical use, reducing climate-damaging emissions, and producing healthy food.
The authors explain that evolutionary plant breeding applied at the farm level involves cultivating a variety of genetically diverse crops (agrobiodiversity), sometimes planted as seed mixtures. Farmers choose varieties – and mixtures of different varieties – that are well adapted to local conditions. Breeders and farmers work to ensure that there is enough genetic variation within the populations of crops to allow the plants to continually adapt to evolving conditions, including the changing climate.
Evolutionary plant breeding can even produce yields in organic systems that are comparable with those of modern cultivars, according to the authors.
"Climate-smart" crops of GMO and intensive ag are set to fail
This dynamic approach contrasts with the route taken by proponents of GMOs and intensive agriculture, who hype their (as yet non-existent) products using the terms "climate-smart crops" and "climate-smart agriculture". The review authors hold that these terms are misleading and that the strategies suggested are more likely to fail, as they focus narrowly on the incorporation of traits conferring tolerance or resistance to specific environmental stresses, such as fungal diseases, weeds, certain insect pests, and drought. Therefore they cannot cope with "the evolving nature of the challenge". If drought gives way to excessive rain, or a new pest or disease appears as a result of climate shifts, the specific "climate-smart crop" will crash.
The review authors appear confident in the ability of evolutionary plant breeding within organic and agroecological systems to cope with and mitigate the challenges of climate change. But in the second of their two reviews, they point to a problem – the potential for organic agriculture to feed the world is largely unexplored, due to the limited number of breeding programs addressing the need for varieties specifically adapted to organic systems. This means that organic farmers often cannot find organically produced seed of suitable varieties.
The authors address this problem by describing a plant breeding scheme that combines evolutionary breeding with "decentralized and participatory selection" – selection of seeds or other planting material conducted within each target environment, with the participation of farmers. This approach is opposite to that of industrial agriculture, which attempts to smooth out variations in weather and soil conditions by blanket application of pesticides (including built-in ones like Bt toxins) and fertilisers, along with highly specialised seed, which is typically planted in large monocultures.
The approach has to fit within a breeding programme, which usually involves three stages:
1) Generating genetic variability, including selecting parents, cross-breeding, and introduction of germplasm from gene banks, other breeding programmes, or farmers
2) Selection of the best genetic material – a step that can involve marker assisted selection, a biotechnology that does not in itself result in a GMO
3) Testing of breeding lines.
The participation of users (farmers) must happen at the very beginning of the breeding programme, to ensure that the varieties developed will be accepted by the target market.
The system works best when practised as a community. Several farmers growing evolutionary populations of crops in areas with similar characteristics insures against loss from a catastrophic event affecting any one farmer.
Bottom-up vs top-down
GMWatch notes that the approach described by the researchers could be termed "bottom-up", in stark contrast to the "top-down" approach of GMO developers. An example of the latter is golden rice, a GM product that the development experts Glenn Davis Stone and Dominic Glover describe as "profoundly disembedded and placeless: an invention of European biologists who used primarily American funding to insert DNA from scattered locations across the biological kingdoms to alter Green Revolution rice in order to treat malnourished children of Asia, partly to help fight a global public relations war".
The result, they say, is a "generic" product that has proved difficult to breed into locally adapted varieties. In the Philippines, the main target market, it failed to produce satisfactory yields, though it has been approved for commercial production. And attempts to breed the trait into Indian varieties resulted in stunted and deformed plants.
Pointing to the poor "standards of productivity" that plagued golden rice throughout its development, Stone and Glover note that the Philippines is a country of competing rice futures. While GM golden rice has been rolled out in the country by the International Rice Research Institute (IRRI) in textbook top-down fashion, the IRRI is also promoting heirloom rice varieties, which are adapted to specific conditions and cultivation practices in localised regions of the Philippines.
Which model will succeed in the long term? To us at GMWatch, it is clear that the localised and diversified approach – incorporating evolutionary plant breeding – is the sustainable one. But it will only prevail in the foreseeable future if the heirloom varieties are not decimated or wiped out by the top-down mass introduction of GMOs like golden rice. The cautionary tale here is that of India, where many hardy "desi" or native varieties of cotton were replaced by the pest-prone GM Bt version, leaving farmers suffering from the failure of the latter with nowhere to turn.
Based on evidence presented in the new reviews, evolutionary plant breeding within organic and agroecological systems appears to offer the most practical solution to the challenges of climate change, as well as a way out of the culture of dependency and destructiveness that GMO and agrochemical systems create.
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The new reviews:
Ceccarelli, Salvatore, and Stefania Grando. Evolutionary plant breeding as a response to the complexity of climate change. Iscience (2020): 101815.
https://www.cell.com/iscience/pdf/S2589-0042(20)31012-9.pdf
Ceccarelli, Salvatore, and Stefania Grando. Organic agriculture and evolutionary populations to merge mitigation and adaptation strategies to fight climate change. South Sustainability 1.2 (2020): e013-e013.
https://revistas.cientifica.edu.pe/index.php/southsustainability/article/download/730/736
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