I’m interested in this topic, and I think my interest tends towards being able to come up with an appropriate definition of productivity for landrace gardening so that it can be compared in those terms to the vigor and productivity of conventional F1 hybrids. I am currently reading One Straw Revolution for the first time, and I’m sure Fukuoka is influencing my thoughts on framing.
In terms of the academic literature, at some point I am pretty sure I had access to the full text of the chapter I’m linking below, but at the moment I don’t seem to be able to access it. In my recollection, it speaks to this, but I am hoping that you all might have credentials where you can pull up the whole thing. If not, I can see if I can find someone at an institution who can access this on my behalf.
Edit: If I recall correctly, what they are referring to as “participatory plant breeding” is participatory breeding with “evolutionary populations”, which is akin to landrace gardening.
Here’s the abstract:
Despite its demonstrated efficiency, participatory plant breeding (PPB) has not gained widespread acceptance. Selection theory and variety adoption dynamics provide the scientific basis of PPB. Decentralized selection (selection in the target environment) yields greater genetic gains, particularly with heterogeneous target populations, as is common in marginal environments. Moreover, when the efficiency of a plant breeding programme is measured by both the genetic gain and by a measure of adoption, PPB has been shown to increase the probability of adoption, biodiversity and hence nutritional quality; it also has a higher benefit/cost ratio than non-participatory breeding. However, PPB has failed to gain favour even in institutions working to reduce poverty and malnutrition, promote improved livelihoods and assist marginal farmers. Its wider adoption has been hindered by reluctance to accept the implicit paradigm shift regarding seed sovereignty and food sovereignty. We propose evolutionary participatory plant breeding (EPPB) as an alternative: it has many of the advantages of PPB, but is more effective in bringing back diversity in farmers’ fields without necessarily requiring the support of a scientific institution.
The purpose of this graph is to demonstrate a technique called PCA; the goal of it is mostly just to suss out behavioral trends. Given all of the data they collected: plant height, plant temperature, time to maturity, yield, spike number, etc … can we create broad groupings or predictions about the behaviors of the plants? Do some traits imply or predict other traits? PCA can take all of these variables and try to ‘compress’ them down based on the assumption that traits are sometimes likely to be correlated. Because we can’t very easily visualize a 8-dimensional graph.
As you see, there is a distinct separation between the modern cultivars (blue) and the landraces (orange). There’s also a distinct separation between the ‘Arid, Low Irrigation’ environment, all of those squares bunched up on the left hand side. The gulf between modern cultivars and landraces was narrowed in that stressful environment. But overall the modern cultivars still yielded more, even then.
The study found that thousand kernel weight (TKW) and yield (GY) were highly correlated, which is what the red arrows on the original picture are suggesting (they point in about the same direction, toward the modern varieties). Plant height and time to maturity (GDDtH and PH) were more associated with landraces, the arrows pointing to the bottom right corner. Higher temperatures (CT) generally meant fewer plant spikes, less spike weight, and less dry matter (SPN, SpW,DM_M), so those arrows are pointing in opposite directions. The fact that temperature arrow is pointing directly into the low-irrigation arid environment shows that intuitively. The Coastal High Irrigation environment (down triangles) had lower temperatures and higher dry matter/spike measurements.
I looked into what these ‘modern varieties’ actually are and I couldn’t find hardly any information about them online. I did find that one of them is a GMO variety. I couldn’t find exact information about the farms where these were grown, but based on the naming conventions they appear to be roughly west of Jerusalem.
Yes, I also read that when it was freely available, not sure why they decided to limit access! But you can request a copy from the authors here: https://www.researchgate.net/publication/336233377_From_participatory_to_evolutionary_plant_breeding
If I recall correctly, they went through a whole explanation of why it was a great thing for grains and then said it couldn’t work for vegetables … huh? (or maybe that was another article).
I have used this research review as a source for the wikipedia article on plant breeding. It speaks to the question of how to define the potential advantages of diverse crops in order to compare to conventional cultivars.
…two causes of the controversy are the range of environmental variation sampled and the type of genetic (or breeding) material being used, and most of the studies comparing the two strategies are biased either because they use a narrow range of environments, or because breeding material selected for specific adaptation is not included.
Breeding for specific adaptation is particularly important in the case of cropspredominantly grown in unfavorable conditions, because unfavorable environments tend to be more different from each other than favorable environments (Ceccarelli and Grando, 1997)… Breeding for specific adaptation to unfavorable conditions is often considered an undesirable breeding objective because it is usually associated with a reduction of potential yield under favorable conditions.
This issue has to be considered in its social dimension and in relation to the difference between adaptation over space vs. adaptation over time: for example Australian farmers prefer maximizing yield in favorable years, while for North African and Near East farmers yield in very poor years is more important.
However, the most serious limitation of decentralized selection for specific adaptation to unfavorable environments is in the large number of potential target environments. Moreover, the number of target environments increases if we consider that environment is not only climate, soil, agronomic practices, farming system, etc., but also people leaving in that physical environment, their perception of risk associated with yield variation over time, their usesof the crop, and the consequent importance of quality traits even if neutral in terms of adaptation to the physical environment. Clearly, selection for specific adaptation to unfavorable conditions needs a larger sample of selection environments than selection for favorable environments
Bread wheat is cultivated globally and is currently the major staple crop in temperate zones. After maize, wheat is the most important grain crop, cultivated in South Africa. ‘Ancient’ wheat landraces were cultivated commonly in the past, but are today only grown on a small area in some countries for traditional foods. Because they have been proposed to be rich sources of bioactive components these historical wheat landraces, compared to current wheat cultivars on the market, are believed to produce higher value food products with enhanced health benefits. In South Africa there has been a renewed interest in older wheat cultivars, such as Witwol, by farmers producing wheat for niche markets. Bolane and Makaloate are cultivars planted traditionally in the highlands of Lesotho. To determine how these older and traditional cultivars compare with modern wheat cultivars on the market, Witwol, Bolane and Makaloate were compared to dry land wheat cultivars, currently on the market in South Africa, with regard to Russian Wheat Aphid (RWA) resistance, yield, hectolitre mass, protein content, mixing time and loaf volume. Since these ‘heritage’ and traditional wheat cultivars are low yielding in comparison with modern wheat cultivars on the market and not adapted to modern agricultural practices, they will not contribute to feeding the growing world population, but the re-introduction to the market and use of ‘heritage’ and traditional wheat cultivars might have a place in markets where its holistic use as crop is a viable option for producers, millers and bakers who cater for specific consumer markets. Encouraging the cultivation of these cultivars will also increase the biodiversity of our food products.
Diverse landraces of maize have been cultivated for centuries in the southwestern United States and northern Mexico primarily for human food consumption. A striking feature of these landraces is the wide array of kernel colors displayed. Traditional cultivation is declining, but blue maize has received increasing commercial interest due to rising consumer demand for unique food products with health benefits and special culinary uses. We evaluated grain yield, agronomic and morphological traits, and analyzed the kernel biochemical composition of five blue and one purple landraces representative of diversity in the Southwest. These were compared with selected open-pollinated populations derived from Southwest and Corn Belt blue maize at several New Mexico locations in 2012 and 2013. Kernel amino acids, oil, protein, starch, fatty acids, crude fiber, ash and anthocyanin pigment contents were determined. Grain yield across all locations, years, and accessions averaged 2.11 Mg ha−1. Navajo Blue and Hopi Blue were the highest and lowest yielding accessions, respectively. The majority of southwestern landraces displayed higher oil content, and two displayed higher protein content, than the Corn Belt Dent variety. Little variation in total amino acid content was observed. Several southwestern floury accessions displayed ∼10% greater lysine and methionine than did dent or flint genotypes. Considerable variation for plant, ear, and kernel compositional traits within and across southwestern landraces was consistent with the presence of racial admixtures. The health-promoting properties of anthocyanin-rich landraces contribute to sound dietary nutrition and human health. This study further illustrates the diversity of southwestern maize and supports the rationale for their continued conservation through sustained cultivation and utilization. Directed selection to improve grain yield and uniformity will be necessary to enhance their potential for commercial production.
Note: I haven’t gotten a copy of this text yet, but I am pretty sure it is relevant to this topic. Probably someone at ttps://www.reddit.com/r/Scholar/ will run off a PDF of this if asked
Plant landraces represent heterogeneous, local adaptations of domesticated species, and thereby provide genetic resources that meet current and new challenges for farming in stressful environments. These local ecotypes can show variable phenology and low-to-moderate edible yield, but are often highly nutritious. The main contributions of landraces to plant breeding have been traits for more efficient nutrient uptake and utilization, as well as useful genes for adaptation to stressful environments such as water stress, salinity, and high temperatures. We propose that a systematic landrace evaluation may define patterns of diversity, which will facilitate identifying alleles for enhancing yield and abiotic stress adaptation, thus raising the productivity and stability of staple crops in vulnerable environments.
