Kristoffer Ring

• Wendmu, Tsedal Asres; Semere, Tesfakiros; Kovi, Mallikarjuna Rao; Ring, Kristoffer; Boer, Hugo de & Abera, Fetien Abay [Show all 7 contributors for this article] (2023). “People Gathered by Sorghum”: Cultural Practices and sorghum Diversity in Northern Ethiopia. Human Ecology. ISSN 0300-7839. 51, p. 923–935. doi: 10.1007/s10745-023-00442-9. Full text in Research Archive Show summary

  Abstract Sorghum is an important crop in the livelihoods of Kunama and Tigrayan farmers in Northern Ethiopia and we present here a study of what factors have shaped the genetic diversity of the varieties cultivated in neighboring communities of the two ethnolinguistic groups. Using a combination of methods from crop science and cultural anthropology, we investigate patterns of historical and contemporary relationships between crop genetic diversity and cultural and social factors. The spatial genetic structure reveals patterns of ethnolinguistic differentiation and admixture that reflect deep affinities between cultures and crops, but the seed systems of the two communities are also open to exchange and gene-flow. Our findings highlight the importance of understanding cultural factors for genetic resource conservation, as well as for plant breeding and seed system development efforts.

• Berg, Paul Ragnar; Jentoft, Sissel; Star, Bastiaan; Ring, Kristoffer Hofaker; Knutsen, Halvor & Lien, Sigbjørn [Show all 8 contributors for this article] (2015). Adaptation to low salinity promotes genomic divergence in Atlantic Cod (Gadus morhua L.). Genome Biology and Evolution (GBE). 7(6), p. 1644–1663. doi: 10.1093/gbe/evv093. Full text in Research Archive Show summary

  How genomic selection enables species to adapt to divergent environments is a fundamental question in ecology and evolution. We investigated the genomic signatures of local adaptation in Atlantic cod (Gadus morhua L.) along a natural salinity gradient, ranging from 35‰ in the North Sea to 7‰ within the Baltic Sea. By utilizing a 12 K SNPchip, we simultaneously assessed neutral and adaptive genetic divergence across the Atlantic cod genome. Combining outlier analyses with a landscape genomic approach, we identified a set of directionally selected loci that are strongly correlated with habitat differences in salinity, oxygen, and temperature. Our results show that discrete regions within the Atlantic cod genome are subject to directional selection and associated with adaptation to the local environmental conditions in the Baltic- and the North Sea, indicating divergence hitchhiking and the presence of genomic islands of divergence. We report a suite of outlier single nucleotide polymorphisms within or closely located to genes associated with osmoregulation, as well as genes known to play important roles in the hydration and development of oocytes. These genes are likely to have key functions within a general osmoregulatory framework and are important for the survival of eggs and larvae, contributing to the buildup of reproductive isolation between the low-salinity adapted Baltic cod and the adjacent cod populations. Hence, our data suggest that adaptive responses to the environmental conditions in the Baltic Sea may contribute to a strong and effective reproductive barrier, and that Baltic cod can be viewed as an example of ongoing speciation.

• Westengen, Ola Tveitereid; Okongo, Mark Atam; Onek, Leo; Berg, Trygve; Upadhyaya, Hari & Birkeland, Siri [Show all 10 contributors for this article] (2014). Ethnolinguistic structuring of sorghum genetic diversity in Africa and the role of local seed systems. Proceedings of the National Academy of Sciences of the United States of America (PNAS). ISSN 0027-8424. 111(39), p. 14100–14105. doi: 10.1073/pnas.1401646111. Full text in Research Archive Show summary

  Sorghum is a drought-tolerant crop with a vital role in the livelihoods of millions of people in marginal areas. We examined genetic structure in this diverse crop in Africa. On the continentwide scale, we identified three major sorghum populations (Central, Southern, and Northern) that are associated with the distribution of ethnolinguistic groups on the continent. The codistribution of the Central sorghum population and the Nilo-Saharan language family supports a proposed hypothesis about a close and causal relationship between the distribution of sorghum and languages in the region between the Chari and the Nile rivers. The Southern sorghum population is associated with the Bantu languages of the Niger-Congo language family, in agreement with the farminglanguage codispersal hypothesis as it has been related to the Bantu expansion. The Northern sorghum population is distributed across early Niger-Congo and Afro-Asiatic language family areas with dry agroclimatic conditions. At a finer geographic scale, the genetic substructure within the Central sorghum population is associated with language-group expansions within the Nilo-Saharan language family. A case study of the seed system of the Pari people, a Western-Nilotic ethnolinguistic group, provides a window into the social and cultural factors involved in generating and maintaining the continent-wide diversity patterns. The age-grade system, a cultural institution important for the expansive success of this ethnolinguistic group in the past, plays a central role in the management of sorghum landraces and continues to underpin the resilience of their traditional seed system.

• Westengen, Ola Tveitereid; Ring, Kristoffer Hofaker; Berg, Paul Ragnar & Brysting, Anne Krag (2014). Modern maize varieties going local in the semi-arid zone in Tanzania. BMC Evolutionary Biology. 14(1), p. 1–12. doi: 10.1186/1471-2148-14-1. Full text in Research Archive Show summary

  Background: Maize is the most produced crop in Sub-Saharan Africa, but yields are low and climate change is projected to further constrain smallholder production. The current efforts to breed and disseminate new high yielding and climate ready maize varieties are implemented through the formal seed system; the chain of public and private sector activities and institutions that produce and release certified seeds. These efforts are taking place in contexts currently dominated by informal seed systems; local and informal seed management and exchange channels with a long history of adapting crops to local conditions. We here present a case study of the genetic effects of both formal and informal seed management from the semi-arid zone in Tanzania. Results: Two open pollinated varieties (OPVs), Staha and TMV1, first released by the formal seed system in the 1980s are cultivated on two-thirds of the maize fields among the surveyed households. Farmer-recycling of improved varieties and seed selection are common on-farm seed management practices. Drought tolerance and high yield are the most important characteristics reported as reason for cultivating the current varieties as well as the most important criteria for farmers’ seed selection. Bayesian cluster analysis, PCA and FST analyses based on 131 SNPs clearly distinguish between the two OPVs, and despite considerable heterogeneity between and within seed lots, there is insignificant differentiation between breeder’s seeds and commercial seeds in both OPVs. Genetic separation increases as the formal system varieties enter the informal system and both hybridization with unrelated varieties and directional selection probably play a role in the differentiation. Using a Bayesian association approach we identify three loci putatively under selection in the informal seed system. Conclusions: SOur results suggest that the formal seed system in the study area distributes seed lots that are true to type. We suggest that hybridization and directional selection differentiate farmer recycled seed lots from the original varieties and potentially lead to beneficial creolization. Access to drought tolerant OPVs in combination with farmer seed selection is likely to enhance seed system security and farmers’ adaptive capacity in the face of climate change.

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• Westengen, Ola; Ring, Kristoffer Hofaker & Orozco-Ramirezc, Quetzalcoatl (2016). Crops and culture: conserving the seed heritage. Full text in Research Archive
• Berg, Paul Ragnar; Jentoft, Sissel; Star, Bastiaan; Ring, Kristoffer Hofaker; Knutsen, Halvor & Lien, Sigbjørn [Show all 8 contributors for this article] (2014). Adaptation to low salinity promotes genomic divergence in Atlantic cod (Gadus morhua L.). Full text in Research Archive

View all works in NVA