Reflection on the limitations of modern plant breeding
The following is a review of and reaction to the following paper: Extending Darwin’s Analogy: Bridging Difference in Concepts of Selection between Farmers, Biologist, and Plant Breeders by DA Cleveland and D Soleri
As an aspiring plant breeder, following the traditional route in academia, you learn about both the theory and practice of modern day plant breeding. Likely one will come across the works of Darwin and Mendel, as they are the fathers of this revolution in plant breeding (i.e., they provided the foundation on which ‘scientific selection’ stands upon). This paper attempts to question this foundation, by comparing our modern day assumptions with ideologies of traditional farmers.
So what is selection?
We can divide this term into natural and artificial selection, but all this identifies is whether or not man has had a hand in evolution. Some may postulate that when done, according to scripture, plant breeding is applied evolution. In other words, plant breeders are playing god with their subjects. I have always had a difficult time swallowing this mantra, although the concept of selection=god is a seductive one.
So here I’m bringing up an important bias and that is our lust for control and power. With the revolutionary scientific foundations provided by Darwin and Mendel we understood how to control evolution, and for those in the know, we could create a niche in the marketplace. This is no different than the biotechnology ‘gene jockeys’ of today. All this may have taken a different route if capitalism had been replaced by a more egalitarian participatory democracy, but let’s save that for another time.
Back to selection…
The major distinction between modern and traditional selection is the separation between phenotype and genotype. As modern plant breeders, we chase the genotype. Why? Well, it is understood that genes are inherited while the phenotype is an expression of those genes within an environment. Since we cannot control the environment per se, it makes rational sense to focus on what we can predict…A mechanistic dogma but it has produced results much faster than if only selecting on phenotypic differences. Now let’s not rule out epigenetic influences, although they have effectively been neglected by mainstream practitioners.
Genetic response=evolution…or does it?
Another issue I have with modern plant breeding is its ability to create tremendous amounts of diversity, while narrowing overall diversity. Inherently, selection reduces allelic diversity within a population over time, but it can also lead to an overall genetic response in that population, for instance, size of fruit. Is this evolution? In the short term probably not, because all that was done was the big fruits were propagated, and therefore, made up more of the population in subsequent generations (sounds similar to natural selection, doesn’t it?). Without allelic diversity there is no evolution and it’s only a matter of time before species extinction. This is why as backyard seed savers, we must be aware of our individual limitations and strength in numbers. ‘Artificial’ evolution is only feasible through the diversification of crop species over long periods of time in response to diverse environments. Darwin understood this, “selection does nothing without variability”.
Enter the traditional peasant-farmer…
Without the understanding of genetics, as we know it today, the food producers of the past developed a tremendous variety of inter- and intra-species diversity. Modern plant breeders have succeeded in selecting the best and eliminating much of the remaining over the pasts 100 years. While we will not likely be able to regenerative what has been lost, we may be able to learn from our mistakes and take an alternative, more sustainable path.
“Plant breeders focused on modern varieties widely adapted to more optimal, more intensively managed environments, while many traditionally-based farmers in relatively marginal environments continued to focus on traditional varieties for their diverse, more marginal growing environments.”
Reintroducing the farmers’ varieties or modern landraces—
This can be as simple as collecting modern varieties and planting them in bulk according to a varietal ideotype. Over time these will ‘creolize’ and become more or less adapted to your environment. With judicious inclusion of exotic genetics you can create a resilient modern landrace unique and specific to your growing conditions.
If you do decide to impose some selection on the developing landrace, remember that you are selecting on the phenotype that may or may not be heritable. Your selection may reduce allelic diversity for the good, but it can also bring lots of disappointment, so do so with care and awareness. One simple way to maximize the genetic diversity on a small scale is to select one seed from each plant. Otherwise known as single seed decent, this is the optimal method if you do not have the space to save your seeds in bulk. Ideally a bulk method of breeding, only imposing selection for highest quality during seed cleaning, will maximize the potential for ‘evolution’.
Finally, traditional agriculturists, past or present, are by nature, integrated into the household-community through production, consumption, crop improvement, and genetic conservation ‘customs’. This network has all been consolidated into the hands of a few and we have lost our traditional knowledge. We as backyard seed savers can reverse this trend for the better by relying on one another, be it close or from afar, to foster new community customs and seed sovereignty. We are just as capable of developing resilient germplasm adapted to climate change and suited for consumption on our dinner tables.
“Words and their implicit cultural meanings can have important effects on our understanding of basic biological processes, emphasizing some aspects at the expense of others.”
In Cleveland’s ancillary paper ‘Is plant breeding science objective truth or social construction? The case of yield stability‘ we are introduced to the two ideological goals of modern plant breeders: yield and yield stability.
In this paper, Cleveland uses the many applications of yield stability to highlight that plant breeding, as well as all science disciples are influenced by both objective truth and social construction. These are social science terms but instructive in understanding why things are the way they are and how to come to terms with this dominant paradigm.
Pertinent to understand is that landraces were selected against because they were often heterogenous and locally adapted to marginal growing environments, i.e., static stability. Much of the success of modern plant breeding can be attributed to a refinement of these original landraces, and through blending specific genetics and breeding methodologies the result was an increase in homogeneity, yield, and broad adaptation, i.e., dynamic stability. Now none of this could have been possible without manipulating the environment through the agronomist’s chemical revolution, which makes a lot more sense than Borlaug’s Green Revolution.
Some may argue that we’ve created chemical junkies. Others standby the ‘spillover effect’ where varieties selected under optimal conditions outperform ones that were selected under marginal conditions in these low productive environments. Like Cleveland, a holistic approach may be valuable here. This needs further research but it appears that varieties selected under the intended environment of use are better adapted, i.e., static stability than those selected abroad. Now there are some contingencies: available genetic diversity and selection methodology but the theory appears sound and it is the one all backyard seed savers should head.
So why haven’t we taken the route of specific rather than adopting broad adaptation?
Well follow the $ silly. In other words the dominant structure dictates not only research objectives but characterizes the scientific plant breeder’s ability to reason rationally. As Borlaug dutifully notes, “Increased yields are needed to buy time for society to deal with issues affecting population growth”. Now Borlaug’s shuttle breeding was an ingenious method no doubt, but his ideology followed “Malthusian pessimism” and was a major contributor to industrialization, the rural to urban migration, and loss of in-situ genetic diversity. In other words, “plant breeding always implies an economic advantage for someone”.
Static stability–ideal in marginal environments where ‘traditional farmers’ reduce risk via the genetic security of the varieties in use, which they control and mediate with support of their community, i.e., informed peasantry. Workhorse varieties
Dynamic stability–ideal in optimized environments where ‘progressive farmers’ reduce risk via the genetic uniformity of the varieties in use in combination with a crop protection package and subsidy-ins safety net distributed by third parties, i.e., modern serfdom. Thoroughbred varieties
In conclusion, as backyard seed savers, we can be empowered with the scientific understanding of genetics and plant breeding, but we must also be realistic of our own inherent bias largely via social construction disguised as truth. With an emphasis on static stability of the seeds we save, we can promote a genetically diverse landscape. Through sharing these locally adapted workhorse varieties we may be able to tap into aspects of dynamic stability through genetic complementation at the very least. Even more importantly, however, it allows us to maximize novel-unusual variation, which is why we save seeds in the first place. If you are in it for the money or fame you’ve read the wrong blog. If you are in it for the love, well join us!
