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Ex Situ Conservation of Plant Genetic Resources: Global Development and Environmental Concerns

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Abstract

Conservation of plant genetic resources is achieved by protection of populations in nature (in situ) or by preservation of samples in gene banks (ex situ). The latter are essential for users of germplasm who need ready access. Ex situ conservation also acts as a back-up for certain segments of diversity that might otherwise be lost in nature and in human-dominated ecosystems. The two methods are complementary, yet better understanding of this interrelation and the role of ex situ conservation in global environmental considerations is needed. Inclusion of ex situ conservation efforts within current environmental policies conserving global diversity would focus greater international attention on the safeguarding of these efforts.
... But in situ conservation strategies often have an upper hand over ex situ strategy. The reason is the huge capital required to maintain long-term storage of germplasm (Cohen et al. 1991). Community-based approaches structured and implemented by M.S. Swaminathan are another strategy to safeguard and utilize landrace cultivars with the cooperation of local people, for instance Potato Park situated in Peru (Sonnino 2017). ...
Chapter
Breeders need access to unique genetic variability to meet the growing demand for food while maintaining sustainable agricultural production with the impacts of climate change for generating high-quality nutritional food. Changes in climate and anthropogenic activities and a multitude of environmental influences pose severe threats to food supply and preservation of natural diversity. For example, unpredictable droughts, elevated temperature, and new diseases and pests threaten crop production. Thus, breeding with crop wild relatives (CWR) gives significant resilience to modern agricultural systems and the ability to help sustainably boosting agricultural productivity. As a result, numerous genotype screenings are necessary for broad adaptability, producing a segregating material through fast breeding or rapid generation to shorten the breeding cycle and improving genetic gain. In addition, CWR genomics generates data that support CWR’s usage to boost agricultural genetic diversity. QTL mapping, identifying of candidate genes by next-generation sequencing, gene-based marker development, or significant candidate gene pyramiding of stress-responsive loci in popular cultivar are required to maintain the sustainability of crop production. Thus, genomic data is useful for identifying and isolating novel and dominant alleles of genes from crop gene pools that are agronomically important, which can be used to generate improved crop cultivars. Hence, the natural allelic difference in candidate genes that influences major agronomic characteristics and crop development initiatives is being investigated via allele mining. Among the CWRs of economically important crops, the wild species of rice is essential to improve modern rice cultivars. The awareness of novel genetic and genomic approaches of rice genetic resources for efficient utilization is crucial. Further, their conservation status and availability have not been quantified globally. As a result, a joint effort is required to improve the conservation and accessibility of crop wild relatives for rice breeding. Keywords: Genomics of CWR, Crop improvement, Rice genetic resources
... Given the short average dispersal distances of cycad pollen and seeds (Hall and Walter 2013), this would maximise the chance of collecting genetically diverse and unrelated individuals. Offspring produced by cross-pollinating these more or less unrelated individuals would have a lower risk of inbreeding depression and therefore increase the chance of successful reintroductions into the wild (Cohen et al. 1991). Without insight into the genetic diversity of ex-situ collections, inbreeding depression due to a narrow genetic base could become a problem among ex-situ collections, and any wild populations subsequently established from reintroductions (Enßlin et al. 2011). ...
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Understanding the genetic diversity of wild populations is fundamental to conserving species in-situ and ex-situ. To aid conservation plans and to inform ex-situ conservation, we examined the genetic diversity of the cycad Cycas calcicola (Cycadaceae). Samples were collected from wild populations in the Litchfield National Park and Katherine regions in the Northern Territory, Australia. Additional samples were obtained from botanic garden plants that were originally collected in the Katherine region, Daly River and Spirit Hills in the Northern Territory, Australia. Using RADseq we recovered 2271 informative genome-wide SNPs, revealing low to moderate levels of gene diversity (uHe = 0.037 to 0.135), very low levels of gene flow, and significant levels of inbreeding (mean FIS = 0.491). Population structure and multivariate analysis showed that populations fall into two genetic groups (Katherine vs Litchfield + Daly River + Spirit Hills). Genetic differentiation was twice as high between populations of the Katherine and Litchfield regions (FST ~ 0.1) compared to within these two regions (FST ~ 0.05). Increasing population fragmentation together with high levels of inbreeding and very little gene flow are concerning for the future adaptability of this species. The results indicated that the ex-situ collections (1) had significantly lower genetic diversity than the wild populations, and (2) only partly capture the genetic diversity present, particularly because the Litchfield National Park populations are not represented. We recommend that ex-situ collections be expanded to incorporate the genetic diversity found in Litchfield National Park and to increase the number of representatives from Daly River/Spirit Hills, and that in-situ populations from the Katherine and Greater Litchfield regions be conserved as separate management units.
... Although in situ conservation maintains the original ecosystem and natural habitat of plants better than ex situ preservation, it requires a large cultivation area and large investments of labor, materials, finances, and time for administration and management. Ex situ preservation acts as a backup for certain aspects of diversity that might otherwise be lost in human-dominant ecosystems and in nature [5][6][7]. Forest trees require a long period and large area for growth, and ex situ preservation is commonly used to protect plant resources. This method is convenient for breeders as it, allows research to be carried out in in a timely and efficient manner [8,9]. ...
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To select elite Robinia pseudoacacia L. germplasm resources for production, 13 phenotypes and three physiological indicators of 214 seedlings from 20 provenances were systematically evaluated and analyzed. The leaf phenotypic and physiological coefficients of variation among the genotypes ranged from 3.741% to 19.599% and from 8.260% to 42.363%, respectively. The Kentucky provenance had the largest coefficient of variation (18.541%). The average differentiation coefficients between and within provenances were 34.161% and 38.756%, respectively. These close percentages showed that R . pseudoacacia presented high genetic variation among and within provenances, which can be useful for assisted migration and breeding programs. Furthermore, based on the results of correlations, principal component analysis and cluster analysis, breeding improvements targeting R . pseudoacacia’s ornamental value, food value, and stress resistance of were performed. Forty and 30 excellent individuals, accounting for 18.692% and 14.019%, respectively, of the total resources. They were ultimately screened, after comprehensively taking into considering leaf phenotypic traits including compound leaf length, leaflet number and leaflet area and physiological characteristics including proline and soluble protein contents. These selected individuals could provide a base material for improved variety conservation and selection.
... Although there has been a debate, low genetic diversity generally increases extinction risk (Saccheri et al., 1998). Genetic variations or polymorphisms contribute to the viability and evolutionary potential of natural populations (Frankham and Briscoe, 2010); therefore, the assessment of genetic diversity is crucial in understanding the evolutionary history of endangered species and designing effective conservation and management methods (Cohen et al., 1991;Allendorf and Luikart, 2009;Ouborg, 2010). ...
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Narrow-ranged species face challenges from natural disasters and human activities, and to address why species distributes only in a limited region is of great significance. Here we investigated the genetic diversity, gene flow, and genetic differentiation in six wild and three cultivated populations of Thuja sutchuenensis , a species that survive only in the Daba mountain chain, using chloroplast simple sequence repeats (cpSSR) and nuclear restriction site-associated DNA sequencing (nRAD-seq). Wild T. sutchuenensis populations were from a common ancestral population at 203 ka, indicating they reached the Daba mountain chain before the start of population contraction at the Last Interglacial (LIG, ∼120–140 ka). T. sutchuenensis populations showed relatively high chloroplast but low nuclear genetic diversity. The genetic differentiation of nRAD-seq in any pairwise comparisons were low, while the cpSSR genetic differentiation values varied with pairwise comparisons of populations. High gene flow and low genetic differentiation resulted in a weak isolation-by-distance effect. The genetic diversity and differentiation of T. sutchuenensis explained its survival in the Daba mountain chain, while its narrow ecological niche from the relatively isolated and unique environment in the “refugia” limited its distribution.
... To maintain the diversity of cultivated potatoes and their wild relatives in Ecuador, it is necessary to implement conservation strategies in situ (on farm) and ex situ The importance of the complementarity of both systems has already been highlighted by authors such as Engels and Visser (2003), Jarvis et al. (2000) or Castañeda-Á lvarez et al. (2015), although these two conservation methodologies have inherent advantages and disadvantages (Altieri 1987;Brush 1991;Cohen 1991;Dulloo 2010). Currently, thousands of local varieties and wild relatives of the potato are conserved in gene banks (Bamberg et al. 1996;Pavek and Corsini 2001;CIP 2020;Monteros-Altamirano et al. 2018). ...
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Ecuador is one of the centers of diversity for wild and cultivated potatoes. Three micro-centers of diversity were previously identified based on germplasm collecting passport data of potato landraces and their wild relatives. The objective of this study was to understand the potential hybridization dynamic of the genetic diversity present in situ in these micro-centers (provinces of Carchi, Chimborazo and Loja in Ecuador) by means of assessing the possibility of an eventual genetic cross within intercropped potato landraces, or among potato landraces to their wild relatives; besides the mapping of actual geographic location of recent collections of potato landrace and wild potato relatives in the study areas. Information from farmers and eco-geographic data demonstrated that there is no potential crossing between wild and cultivated potato species. Probably the existing genetic variability in Ecuador has been accumulated since the historical movement of potato landraces by American ancestors from the center of origin in Peru and Bolivia and the continuum knowledge and seed sharing besides the conscious and unconscious selection of potato landraces by local farmers for centuries. Additionally, we discuss options to conserve both cultivated and wild potato species in Ecuador due to apparent current genetic erosion processes.
... To maintain the diversity of cultivated potatoes and their wild relatives in Ecuador, it is necessary to implement conservation strategies in situ (on farm) and ex situ. The importance of the complementarity of both systems has already been highlighted by authors such as Engels and Visser (2003) or Jarvis et al. (2000), although these two conservation methodologies have inherent advantages and disadvantages (Altieri, 1987;Brush, 1991;Cohen, 1991;Dulloo, 2010). Currently, thousands of local varieties and wild relatives of the potato are conserved in gene banks (Bamberg et al., 1996;Pavek and Corsini, 2001;CIP, 2020;Monteros-Altamirano et al., 2018). ...
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Ecuador is one of the centers of diversity for wild and cultivated potatoes. Three micro-centers of diversity were previously identified based on germplasm collecting passport data of potato landraces and their wild relatives. The objective of this study was to understand the potential hybridization dynamic of the genetic diversity present in situ in these micro-centers (provinces of Carchi, Chimborazo and Loja in Ecuador) by means of: 1. Reviewing the possibility of an eventual genetic cross within intercropped potato landraces through surveys to local producers; 2. Reviewing the possibility of potato landraces crossing with their wild relatives, also according to local producers; and 3. Map the actual geographic location of recent collections of potato landrace and wild potato relatives in the study areas. Information from farmers and eco-geographic data demonstrated that there is no potential crossing between wild and cultivated potato species. Probably the existing genetic variability in Ecuador has been accumulated since the historical movement of potato landraces by American ancestors from the center of origin in Peru and Bolivia and the continuum knowledge and seed sharing besides the conscious and unconscious selection of potato landraces by local farmers for centuries. Additionally, we discuss options to conserve both cultivated and wild potato species in Ecuador due to apparent current genetic erosion processes.
... Effective scientific approaches to the conservation of plant biodiversity have been developed through various conservation methods, two of them are of greater practical importance: in situ -maintaining collections in the natural environment [4,5] and ex situ -preserving samples at an organismal level. Ex situ storage in seed gene banks is based on the creation of conditions for the reduction of seed metabolic activity, most often as a result of low moisture content and low temperature [6]. ...
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The purpose of this study is to evaluate the condition of a collection of Bulgarian common wheat varieties under ex situ controlled storage after a ten-year period. The studied materials are characterized by high vitality, without negative changes that will lead to the loss of original germplasm. The established moisture in the seeds is high for the purpose of controlled storage. When it rises above 12,5%, a decrease in the values of germination energy is observed. Higher control of initial moisture and germination is required prior to entering the seeds for storage under ex situ conditions.
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Ex situ conservation plays an important role in maintaining global plant biodiversity and protects thousands of wild plants. Plant conservation in botanical gardens is an important part of ex situ conservation; however, little attention has been given to whether plant ecophysiological traits change and whether plant conservation goals are reached following ex situ conservation. In this study, tree and shrub plants were selected from Shanxi, Beijing of China and from Beijing Botanical Garden, and plants with good growth and similar ages were randomly selected to measure their light response curves, CO2 response curves with a portable photosynthesis system (Li-6400XT), relative chlorophyll contents using a chlorophyll meter (SPAD-502) and leaf water potential using a dew point water potential meter (WP4C). In comparison with cultivated plants, wild plants had higher water use efficiencies among all plants considered (by 92–337%) and greater light use efficiencies among some of plants considered (by 107–181%), while light response curves and CO2 response curves for wild plants were either higher or lower compared with cultivated plants. Ecological traits of wild and cultivated plants changed more as a result of habitat factors than due to plant factors. The initial slope of the light response curve, net photosynthetic rate at light saturation, light saturation point, maximum light energy utilization efficiency, maximum water use efficiency, leaf water content, and the leaf water potential of wild plants were larger or equal to those of cultivated plants, while dark respiration rate (by 63–583%) and light compensation point (by 150–607%) of cultivated plants were higher than those of wild plants. This research compared the ecophysiological traits of common green space plants cultivated in botanical gardens and distributed in different areas in wild environments. The response of plant ecophysiological traits to the changing environment has important theoretical and practical significance for wild plant conservation and urban green space system construction.
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Phenotypic variation of 75 accessions of wild Prunus arabica (Olivier) Meikle species was assessed. There were significant variations among the accessions based on the characters recorded. The range of nut-related characters was as follows: nut length: 12.67–18.82 mm, nut width: 8.23–13.74 mm, nut thickness: 6.96–9.73 mm, and nut weight: 0.33–1.12 g. The range of kernel-related characters was as follows: kernel length: 9.74–15.31 mm, kernel width: 5.34–9.32 mm, kernel thickness: 3.51–5.98 mm, and kernel weight: 0.11–0.36 g. Flowering date ranged from late March to early April, and ripening date varied from late May to early July. Nut weight was positively correlated with dimensions of peduncle, petal, calyx, sepal, leaf, and nut. Principal component analysis (PCA) revealed 22 PCs which contributed 85.65% of total variance. The Ward dendrogram revealed the similarities and dissimilarities among the accessions in terms of the recorded characters and divided them into two main clusters. Considerable genetic diversity was observed among P. arabica accessions studied at morphological level, indicating rich and valuable plant materials for almond rootstock improvement. Wild P. arabica species is a potential source for transferring valuable resistances regarding its ability to withstand unfavorable environments.
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Foreign assistance helps developing countries to achieve economic growth through wise use of natural resources. Conservation interventions and sustainable use of natural resources play a central role in this development. Conservation and utilization of genetic resources have traditionally proceeded as separate approaches. A conceptual approach to project design is presented encouraging greater interaction between those conserving crop genetic resources and those seeking their economic application in a sound land-use management plan. Projects illustrating this approach are being supported by the Agency for International Development. They suggest a paradigm for research and development allowing interdisciplinary activities targeting sustainable agriculture development. La ayuda extranjera contribuye a que los países en desarrollo logren un crecimiento económico a través del uso apropriado de sus recursos naturales. La interventión en la conservation y el uso sostenible de recursos naturales debe desempeñar un papel primordial en este desarrollo. La conservatión y utilization de recursos genéticos tradicionalmente se ha considerado como enfoques separados. Presentamos un enfoque conceptual para proyeetar el diseño, estimulando mayor interactión entre esos recursos de productos geneticos de conservación y aquellos que buscan su aplicación económica en un plan bien fundamentado de administratión en el uso de la tierra. La Agènda para el Desarrollo Internationál apoya proyectos que ilustran este sistema. Se sugiere un paradigma para la investigation y el desarrollo permitiendo en estos proyeetos actividades interdisciplinarias que enfoquen el desarrollo de una agricultura sostenible.
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Nature Biotechnology journal featuring biotechnology articles and science research papers of commercial interest in pharmaceutical, medical, and environmental sciences.
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Recent research on genetic and biological diversity suggests that they underlie, and are the source of renewable resources—which are themselves more fundamental than nonrenewable resources. However, recognition of this is hindered by various Western cultural and analytic biases that have generally led to the neglect of informal and natural systems. Signifcant implications flow from this recognition. Analysis and models at the global level—as well as their resource, environmental, and population components—will need to be considerably broadened to in clude the fundamental role of genetic and biological diversity. When this is done, the “limits to growth” debate takes on greater urgency, and the focus shifts. Agriculture is then seen as the key interface between natural and social systems. In addition, the whole notion that Third World countries should model their societies along current industrial lines is fundamentally challenged. At the national level, both industrial and developing countries will need to give priority to developing regenerative rural and agricultural systems To do this, industrial countries will need to move toward “food systems” approaches, while developing countries will need to conserve and build upon existing agroecosystems. This will require new development theories and practices that are more contextual and recognize the nonneutrality of Western technologies and economic theories. Finally, the larger threats posed by modern industrial society to the maintenance or creation of more sustainable and regenerative systems need to be included in any analysis. These include both the threat of nuclear war and the larger “war against nature” in which modem industrial society is engaged New concepts of “national security” are suggested along with corresponding shifts in national priorities.
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Crop Exploration and Utilization of Genetic Resources
  • T T Chang
Plant Population Genetics, Breeding, and Genetic Resources
  • D R Marshall