Genetic Diversity and Erosion—A Global Perspective

Thormann, I.; Engels, Johannes

doi:10.1007/978-3-319-25637-5_10

Cited by 17 publications

(20 citation statements)

References 121 publications

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“…Analysis of wheat polymorphism through the application of different molecular markers (microsatellites, SSR, DNA polymorphism, RFLP, retrotransposons) for different segments of common wheat germplasm permits the conclusion that there are no convincing proofs of genetic erosion in wheat (reviewed in Van de Wouw et al, 2010). Our data provide new insights for discussions (Porceddu et al, 1988;Thormann and Engels, 2015) about possible genetic erosion of wheat germplasm during the 20th century.…”

Section: Discussionmentioning

confidence: 60%

“…There has been a discussion (reviewed in Porceddu et al, 1988;Brown and Hodgkin, 2015;Thormann and Engels, 2015) about possible decreases in the level of genetic diversity (genetic erosion) of wheat germplasm during the 20th century. An important factor which might influence negatively on wheat genetic diversity was the selection, in different countries, for a similar set of wheat characters, for example, for improved end-use (dough) quality.…”

Section: Introductionmentioning

confidence: 99%

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Gliadin genotypes worldwide for spring wheats (Triticum aestivum L.) 2. Strong differentiation of polymorphism between countries and regions of origin

Metakovsky

Мельник

Pascual

et al. 2019

Journal of Cereal Science

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Genotypes of 290 cultivars from ten countries (four continents) of spring wheat Triticum aestivum, were analyzed through the identification of alleles at the gliadin-encoding (Gli) loci. The group of cultivars bred in one country during the 20th century might be characterized by its level of genetic diversity (H) and a specific set of alleles. Strong differences between genotypes of cultivars bred in different countries were confirmed by cluster analysis of genetic distances. Genotypes of cultivars bred in regions of the same country might differ, but they always composed a single cluster and strongly differed from genotypes from other countries or regions. Therefore, world polymorphism of spring wheat germplasm of the 20th century is highly structured and differentiated between countries and their regions. This differentiation seems to be mainly a result of natural selection acting in different ways in different eco-climatic conditions of breeding and propagation. At a regional scale, statistically significant temporal changes in frequency of some gliadin alleles and a tendency to temporal decrease of overall genetic diversity were discovered in cultivars bred in each of seven regions studied in Australia, Canada and the former USSR. In regions of Canada (provinces of Manitoba and Ontario) and of the former USSR (Saratov), a statistically significant decay of the genetic diversity of cultivars bred during the 20th century was discovered. However, the influence of breeders' selection for end-use wheat quality on the wheat genetic diversity was the least, if any.

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Section: Discussionmentioning

confidence: 60%

Section: Introductionmentioning

confidence: 99%

Gliadin genotypes worldwide for spring wheats (Triticum aestivum L.) 2. Strong differentiation of polymorphism between countries and regions of origin

Metakovsky

Мельник

Pascual

et al. 2019

Journal of Cereal Science

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“…This development impacted also indirectly on CWRs, especially those that grew in cultivated fields, on field margins and along roadsides. Consequently, they were included in the global collecting efforts coordinated by IBPGR [9]. The authors reported that 25% of the collecting missions were dedicated to CWRs.…”

Section: General Threat Status Of Cwrmentioning

confidence: 99%

“…Specific examples of global threats leading to genetic erosion of CWR species have been presented by [22,34] and [9]. The latter authors noted much fewer publications on genetic erosion of wild plants and CWRs, compared to those on crop species.…”

Section: General Threat Status Of Cwrmentioning

confidence: 99%

“…As CWRs are difficult to grow, genebanks might tend to wait as long as possible with regenerating them and, thus, seeds might lose their viability and thus cause genetic erosion [43]. The lack of knowledge about the biology of CWR species, the absence of a good infrastructure for their cultivation, and other factors, such as adequate funding for conservation, might well contribute further to genetic erosion, in particular within accessions [9].…”

Section: General Threat Status Of Cwrmentioning

confidence: 99%

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Main Challenges and Actions Needed to Improve Conservation and Sustainable Use of Our Crop Wild Relatives

Engels

Thormann

2020

Plants

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Crop wild relatives (CWR, plural CWRs) are those wild species that are regarded as the ancestors of our cultivated crops. It was only at the end of the last century that they were accorded a high priority for their conservation and, thus, for many genebanks, they are a new and somewhat unknown set of plant genetic resources for food and agriculture. After defining and characterizing CWR and their general threat status, providing an assessment of biological peculiarities of CWR with respect to conservation management, illustrating the need for prioritization and addressing the importance of data and information, we made a detailed assessment of specific aspects of CWRs of direct relevance for their conservation and use. This assessment was complemented by an overview of the current status of CWRs conservation and use, including facts and figures on the in situ conservation, on the ex situ conservation in genebanks and botanic gardens, as well as of the advantages of a combination of in situ and ex situ conservation, the so-called complementary conservation approach. In addition, a brief assessment of the situation with respect to the use of CWRs was made. From these assessments we derived the needs for action in order to achieve a more effective and efficient conservation and use, specifically with respect to the documentation of CWRs, their in situ and ex situ, as well as their complementarity conservation, and how synergies between these components can be obtained. The review was concluded with suggestions on how use can be strengthened, as well as the conservation system at large at the local, national, and regional/international level. Finally, based on the foregoing assessments, a number of recommendations were elaborated on how CWRs can be better conserved and used in order to exploit their potential benefits more effectively.

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Indigenous crop diversity maintained despite the introduction of major global crops in an African centre of agrobiodiversity

Rampersad

Geto

Samuel

et al. 2023

Plants People Planet

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Societal Impact StatementThe global success and expansion of a small pool of major crops, including rice, wheat and maize, risks homogenising global agriculture. Focusing on the agriculturally diverse Ethiopian Highlands, this study tested whether farm diversity tends to be lower among farmers who grow more introduced crops. Surprisingly, it was found that farmers have successfully integrated introduced crops, resulting in more diverse and heterogenous farms without negatively impacting indigenous crop diversity. This is encouraging because diverse farms, comprising indigenous agricultural systems supplemented by introduced crops, may help address global challenges such as food insecurity.Summary The global expansion of a handful of major crops risks eroding indigenous crop diversity and homogenising agroecosystems, with significant consequences for sustainable and resilient food systems. Here, we investigate the farm‐scale impact of introduced crops on indigenous agroecosystems. We surveyed 1369 subsistence farms stratified across climate gradients in the Ethiopian Highlands, a hotspot of agrobiodiversity, to characterise the richness and cultivated area of the 83 edible crops they contained. We further categorise these crops as being indigenous to Ethiopia, or introduced across three different eras. We apply non‐metric multidimensional scaling and mixed effects modelling to characterise agroecosystem composition across farms with different proportions of introduced crops. Crops from different periods do not differ significantly in frequency or abundance across farms. Among geographically matched pairs of farms, those with higher proportions of modern introduced crops had significantly higher overall crop richness. Furthermore, farms with a high proportion of modern introduced crops showed higher heterogeneity in crop composition. An analysis of socio‐economic drivers indicated that poverty is negatively associated with the cultivated area of introduced crops. In our Ethiopian case study, global patterns of major crop expansion are not necessarily associated with agrobiodiversity loss at the farm scale or higher homogeneity across indigenous agricultural systems. Importantly, socioeconomic factors may influence farmers' propensity to adopt novel species, suggesting targets for agricultural extension policies. Given the rapid climatic, economic and demographic changes impacting global food systems and the threats to food security these entail, robust indigenous agricultural systems enriched with diverse introduced crops may help maintain resilience.

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Genetic Diversity and Erosion—A Global Perspective

Cited by 17 publications

References 121 publications

Gliadin genotypes worldwide for spring wheats (Triticum aestivum L.) 2. Strong differentiation of polymorphism between countries and regions of origin

Gliadin genotypes worldwide for spring wheats (Triticum aestivum L.) 2. Strong differentiation of polymorphism between countries and regions of origin

Main Challenges and Actions Needed to Improve Conservation and Sustainable Use of Our Crop Wild Relatives

Indigenous crop diversity maintained despite the introduction of major global crops in an African centre of agrobiodiversity

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