- Domestication history and geographical adaptation inferred from a SNP map of African rice. Evidence of strong selection for salt tolerance over protracted domestication period.
- Genome-Wide Association Study of Resistance to Soybean Cyst Nematode (Heterodera glycines) HG Type 2.5.7 in Wild Soybean (Glycine soja). 43 resistant accessions out of 235.
- Food incursions into global heritage: Peruvian cuisine’s slippery road to UNESCO. How the 1% eat.
- Differentiation and description of aromatic short grain rice landraces of eastern Indian state of Odisha based on qualitative phenotypic descriptors. There’s morphological diversity within aromatic types.
- Genetic Diversity and Population Structure of Cowpea (Vigna unguiculata L. Walp). 768 cultivated types from 56 countries in the USDA collection fall out into 3 genetic groups, but no obvious geographical structure.
- Geography of Genetic Structure in Barley Wild Relative Hordeum vulgare subsp. spontaneum in Jordan. 3 genetic groups again, and no geographic or climatic structure, again.
- Utilization of a high-throughput shoot imaging system to examine the dynamic phenotypic responses of a C4 cereal crop plant to nitrogen and water deficiency over time. Who needs morphological descriptors?
- Establishment of a Core Collection of Traditional Cuban Theobroma cacao Plants for Conservation and Utilization Purposes. 185 out of 537 hardly seems worth it.
- Promotion and Utilization of Niche Foods for Food and Nutrition Security. Termites with your spider plants, madam?
- The History of Wheat Breeding in Tajikistan. Seems, according to the authors, to have been a waste of time.
African rice: Interesting that a wild population bottleneck began more than 10,000 years ago and reached its peak 3,500 years ago – before domestication. We are always told that domestication is the bottleneck for species (and that we therefore need wild species to breed for diversity). They see: “a protracted period of population size reduction likely commencing with predomestication management and/or cultivation.” That sounds like a bad guess. More likely an environmental change, possibly associated with the spread of trees and/or the pre-domestication opening of habit (for hunting) by seasonal burning. And what about the idea if the species was having a bad time (as it seems) then it was domesticated to preserve a food resource (I think this happened with wild cereals in the Middle East associated with tree spread 10,000 years ago).
What’s your point Dave? That you disagree with the idea that the population decline started with precultivation? Great, but why not take it up directly with the authors?
Jeremy: Thanks. Your last point first. As this is an open forum, the authors can jump in and comment: overall, it was an interesting paper. As to contacting authors direct, forget it. We did this after the publication of the Zhu et al. paper on rice mixtures and disease in `Nature’ in 2000 with no joy whatever. This paper has been repeatedly cited as showing that varietal mixtures were a method of disease control. Not so – the paper was a misinterpretation of the facts. The actual mechanism is closer to immunization/vaccination to eliminate human disease. The main variety – up to 90% of the crop – was a disease resistant modern hybrid rice. Over a few years this variety eliminated the blast regionally and allowed the susceptible local variety to thrive (albeit at a low proportion of the rice crop). This was not a mixture effect but an immunization effect.
But the paper is important in its view of concepts of the `domestication bottleneck’. Another paper (cited below) adds a further dimension: “einkorn underwent no reduction of diversity during domestication”… “domestication events at numerous villages would have allowed the newly domesticated lines to integrate a full arsenal of wild haplotypes: many independent domestication bottlenecks would result in no domestication bottleneck for the domesticate lines as a whole”. “Notably, there are other examples known of domesticate plants for which no reduction in genetic diversity in the comparison of wild and domesticate forms was found, including chicory (Van Cutsem et al. 2003), bell pepper (Hernandez-Verdugo et al. 2001), and pepino (Blanca et al. 2007).” “… the data indicate that a specific wild einkorn race that arose without human intervention was subjected to multiple independent domestication events.”
[Kilian, B., Özkan, H., Walther, A., Kohl, J., Dagan, T., Salamini, F., & Martin, W. (2007). Molecular diversity at 18 loci in 321 wild and 92 domesticate lines reveal no reduction of nucleotide diversity during Triticum monococcum (einkorn) domestication: Implications for the origin of agriculture. Molecular Biology and Evolution, 24(12), 2657–2668. http://doi.org/10.1093/molbev/msm192%5D
On your first point, you say that I “disagree with the idea that the population decline started with precultivation”: but I don’t. I disagree with their supposing that it is likely that people were involved in the genetic bottleneck or that it had anything to do with domestication. If pushed I would suggest that any genetic bottleneck (or better, the conditions that brought it about) was the cause of domestication, rather than the result of human behaviour implied by the term `domestication bottleneck’. And the possible natural driver of populations crashing and a subsequent genetic bottleneck could have been the massive climate change leading into and out of the Younger Dryas more than 10,000 years ago. “Both the onset and departure were abrupt, with a rate of temperature change of 7° Celsius in 50 years: note that this rate of warming at the end of the Younger Dryas is double the worst case scenario of the Intergovernmental Panel on Climate Change.” [quoted from Ch. 3 of our 2011 `Agrobiodiversity’ book]. After the end of the Younger Dryas and faced with the rapid spread of trees taking over grasslands that were a major food source of gathered wild cereals, humans would be forced to rescue the relic (and genetically depauperate?) populations of wild cereals or starve to death.
The hints of past rapid climate oscillations associated with pre-domestication genetic bottlenecks could guide better targeted collection of CWRs (rather the generic belief in a `domestication’ bottleneck causing genetic narrowing).