Genetic changes in marine aquaculture species and the potential for impacts on natural populations.

Conservation of genetic resources for sustainable aquaculture

Use and exchange of aquatic genetic resources in aquaculture: information relevant to access and benefit sharing

The worldwide use of Nile tilapia (Oreochromis niloticus Linnaeus, 1758) in aquaculture represents a somewhat unique scenario. The natural distributions and global genetic resources of tilapias are in Africa, yet the main centers of utilization for aquaculture are primarily in Asia. Within a few decades, Nile tilapia graduated from being an ‘orphan commodity’ (i.e. of interest to only resource‐poor fish farmers) to a globally traded commodity. Most aquaculture production of Nile tilapia in Asia and elsewhere has relied on a narrow genetic base. The natural genetic resources have not yet been fully documented and tapped for use in aquaculture, and many natural populations are under severe threat of irreversible change or loss. Although genetic improvement is now well underway, an important question is how the wealth of Nile tilapia wild genetic resources shall be used for the benefit of a wide range of users, at present outside Africa. This review focuses on documenting the status of Nile tilapia genetic resources (including the potential threats), providing a case for their conservation and for the judicious utilization of genetic diversity for the benefit of all stakeholders; and on analysis of the lessons learnt from a major Nile tilapia genetic improvement initiative, the genetic improvement of farmed tilapia (GIFT) project. Information about other genetic improvement efforts by means of hybridization, sex reversal and YY male technology is also presented.

Access to biodiversity for food production: Reconciling open access digital sequence information with access and benefit sharing

The natural genetic diversity of agricultural species is an essential genetic resource for breeding programs aiming to improve their ecosystem and production services. A large natural ecotype diversity is usually available for most grassland species. This could be used to recombine natural climatic adaptations and agronomic value to create improved populations of grassland species adapted to future regional climates. However describing natural genetic resources can be long and costly. Molecular markers may provide useful information to help this task. This opportunity was investigated for Lolium perenne L., using a set of 385 accessions from the natural diversity of this species collected right across Europe and provided by genebanks of several countries. For each of these populations, genotyping provided the allele frequencies of 189,781 SNP markers. GWAS were implemented for over 30 agronomic and/or putatively adaptive traits recorded in three climatically contrasted locations (France, Belgium, Germany). Significant associations were detected for hundreds of markers despite a strong confounding effect of the genetic background; most of them pertained to phenology traits. It is likely that genetic variability in these traits has had an important contribution to environmental adaptation and ecotype differentiation. Genomic prediction models calibrated using natural diversity were found to be highly effective to describe natural populations for almost all traits as well as commercial synthetic populations for some important traits such as disease resistance, spring growth or phenological traits. These results will certainly be valuable information to help the use of natural genetic resources of other species.

Outside of Asia exotic tilapiine fishes (Trewavas 1983) were not imported directly as native genetic resources from Africa but arrived as transits from third or fourth party sources. Founder populations of exotic tilapia species may be morphologically and meristically distinct in Africa but are still reproductively compatible due to their relatively recent divergence. As a result, feral tilapias have hybridized and introgressed in aquaculture settings before escaping to the wild. Reproductively viable hybrids have resulted, making the use of conventional systematics based upon external morphometric characterizations for species determinations useless. Microsatellite DNA marker studies of 139 tilapia from 10 locations (6 feral, 4 in culture) in southern California, USA, were conducted. Genetic similarities to a worldwide tilapia genetic database were compared by formulating a neighbor-joining dendrogram. The hypothesis that the pattern found arose by chance was tested by bootstrap resampling of 4 microsatellite loci at the 95% level of significance. A significant number of bootstrap re-samples showed that a tilapia species in aquaculture and a feral Colorado River tilapia population were 'monophyletic', meaning they originated from a single source relative to the total variation in the data. A significant number of bootstrap re-samples grouped these two populations with the reference populations of Oreochromis niloticus taken worldwide. This 'niloticus' group was found significantly distinct from a second large grouping that included all of the other California tilapia samples and a large group of O. mossambicus reference samples taken from a worldwide database. Any regulatory structure attempting to control movements of exotic tilapias based upon discerning 'species' using morphometric and meristic measurements of tilapias is inadequate. California, for example, does not permit O. niloticus for aquaculture, but the genetic signature for this species exists in feral stocks collected from the wild in California. There are likely many other places where a certain tilapia `species' are not permitted but the genetic material exists in established wild stocks within its political jurisdiction. It is recommended that a system of ecotypes (code names) based upon presence of unique DNA microsatellite markers be developed to label and regulate feral tilapia strains, and that hybrid strains be collected into a 'registry' of species based upon unique DNA markers. Such a registry could be used by regulators to better manage exotic tilapias and aquaculture developments.

Fruit crop is an important industry Brazil, being one of the first fruit production the world. Brazil is also one of the most important centers of genetic diversity for several important tropical fruits. The Brazilian plant genetic resources conservation model is composed by a National Genetic Resources and Biotechnology Research Center - CENARGEN, Brasilia-DF, and a network of genebanks spread out over the country's Research Units, Universities and State Institutions. CENARGEN is one of the 39 Research Units of the Brazilian Agriculture Research Corporation (EMBRAPA). At EMBRAPA the conservation of tropical and subtropical fruits genetic resources comprise 24 field genebanks. Along with several other germplasm collections this system has about 300 species and more than 10000 accessions under conservation, including duplications. All materials are maintained the field, except a small collection of banana and pineapple germplasm which is maintained in vitro. Brazil has a strong collecting program for native species, such as pineapple, cashew and passion-fruit, and for exotic species, such as banana, mango and citrus a good exchange program is maintained. Morphological and molecular characterization, and evaluation of the most important tropical and subtropical fruit germplasm is progress the active genebanks and at Embrapa Genetic Resources and Biotecnology Research Center. The germplasm documentation has been updated through a national information system named Brazilian Genetic Resources Information System - SIBRARGEN. Tropical and subtropical fruits genetic resources, such as pineapple, banana, citrus, mango and cashew are being used breeding programs and correlated research. In this paper, the number of accessions per species, and the location where the collections are maintained are presented as well as other important data on conservation of tropical and subtropical fruits are discussed.

Fruit crops are an important industry in Brazil, which is one of the biggest fruit producers in the world. Brazil is also one of the most important centers of genetic diversity of several important tropical fruits. The Brazilian plant genetic resources conservation model is composed by Embrapa Genetic Resources and Biotechnology (National Genetic Resources and Biotechnology Research Center - CENARGEN), in BrasiliaDF, and by a network of genebanks spread all over the country in Research Units, Universities and State Institutions. CENARGEN is one of the 39 Research Units of the Brazilian Agriculture Research Corporation (EMBRAPA). At EMBRAPA the conservation of tropical and subtropical fruit genetic resources is formed by 24 genebanks. Along with several other germplasm collections, this system has about 300 species and more than 10,000 accessions under conservation, including duplications. All material is kept the field, except for a small collection of banana and pineapple germplasm which is maintained “in vitro”. In this paper, the number of accessions per species, and the location where the collections are kept is presented. Brazil has a strong collecting program for native species including pineapples, cashews and passion fruits. For exotic species, such as bananas, mangoes and citrus, there is a good exchange program. Morphological and molecular characterization, and evaluation of the most important tropical and subtropical fruit germplasm is in progress in the active genebanks and at EMBRAPA Genetic Resources and Biotechnology. The germplasm documentation uses the updated national information system SIBRARGEN. Tropical and subtropical fruit genetic resources, such as pineapples, bananas, citrus, mangoes, and cashews are actively being used in breeding programs and correlated research.

The world’s botanical gardens house some 80,000–100,000 species, and ca. 15,000 species hereof are threatened in the wild. However, representation of natural biodiversity is imbalanced. There is strong bias towards certain plant families and genera, and towards certain functional groups. Apart from this, bias towards species from temperate regions as a result of the imbalance in geographic distribution of botanical gardens is obvious. Tropical regions and the southern hemisphere are highly underrepresented. Most species cultivated in botanical gardens are on an average represented by only two or three specimens, and the genetic diversity within wild species is not reflected. Further limitations include poor documentation and poor maintenance. These limitations reduce the value of the collections as plant genetic resources. However, botanical gardens are the standard institutions for ex situ conservation and propagation of wild plants and should be the main authorities for wild plants. With their huge collections on display botanical gardens are the most effective multipliers for increasing public awareness of the value of biodiversity and conservation needs. There is growing awareness of the ecological, economic and cultural significance of wild plant species and their potential value as genetic resources. Botanical gardens should establish seed gene banks for wild plants for promoting integrated conservation efforts and for protection and conservation of our natural plant genetic resources. They should establish database networks and should provide information services for science, politics and the general public. Botanical gardens play a significant role in promoting public awareness of the value of biodiversity. They have a remarkable potential to contribute to the conservation of plant genetic resources. PLANT GENETIC RESOURCES The Convention on Biological Diversity (CBD) defines genetic resources as “genetic material of actual or potential value” (CBD 1992, article 2), in which “genetic material” means any material of plant, animal, microbial or other origin containing functional units of heredity. Plant genetic resources (PGR) “represent plants or parts of plants which are capable of generative or vegetative propagation with actual or potential value” (FAO Commission on PGR). Plant genetic resources may be classified into eight groups according to the respective conditions for use and conservation (Keller et al., 2002): agricultural crops (food, fodder, raw material); pasture plants (meadows and pastures for fodder production); vegetables; fruit crops (fruit trees and shrubs); special crops (medicinal plants, spices, aromatic and dye-plants); ornamentals (flowers, shrubs, ornamental woody plants); forest plants; wild plants. About 30,000 plant species are considered edible. Of these, 7,000 have been cultivated or collected by humans (FAO, 1998). About 120 food crops are of importance on a national scale. Only 30 crop species make up 90 % of the worlds calorie intake. In some countries, especially Africa and South America, wild species contribute a significant source of food in addition to cultivated species. The markets for plant genetic resources products is immense and according to Ten Kate and Laird (1999) annually somewhere between 500 and 800 billion US $.

Qatar is firmly committed to conserving its biodiversity and is party to the Convention on Biological Diversity and within this the Global Strategy for Plant Conservation (GSPC), and has developed its own National Biodiversity Strategy and Action Plan (NBSAP). Based on an assessment of the status of biodiversity in the country, Qatar's NBSAP identified a total of 11 strategic goals that identify the most pressing biodiversity issues in Qatar including; protected areas, agro biodiversity and desertification, scientific research, education and public awareness. Qatar is home to unique and important habitats, but due to changes in land use and increased development, habitat reduction has emerged as a significant threat to its biodiversity. Qatar is distinguished for its diverse flora that consists of nearly 420 plant species which pave the way for the establishment of the basis gene bank. In accordance with the international conventions which Qatar has recently joined and ratified, the gene bank has conducted ecogeographical surveys about the plant genetic resources. As a result of conducting these surveys, a complete set of seed plants of the Qatari plants genetic resources are conserved as well as integrated database is created to facilitate electronic exchange among relevant stakeholders and countries to use the resources for studies, research, food security and development. A conservation plan is addressed to conserve plant genetic resources to face the challenges of food security in Qatar. This plan is based on Qatar national biodiversity strategy and action plan 2004 and Ministry of Environment national strategy projects 2011–2016. In this study, we focus on the project of Plant Genetic Resources Conservation in Qatar, the project has addressed in five key objectives; plant and seed conservation, molecular genetic characterization, training and capacity building, documentation of Qatar plant genetic resources, and increasing awareness of plant genetic resource's value. We reported that genetic resources department “gene bank” have been collected and conserved 210 seed accessions, 2800 herbarium specimens, and 287 Plant sample for Genetic characterization. On the other hand department of agricultural research start developing field gene bank. Plant genetic resources conservation, including all seed processing and treatments in gene bank “seed cleaning, seeds drying, seed quality test, seeds viability test, seeds germination test as well as store seed at storage rooms. Gene bank make available the conserved germplasm (genetic resources) to several groups of breeders, researchers, graduate and undergraduate students, farmers and other stakeholders. On the other side, we implemented several workshops and training courses about seed conservation in gene bank and access to plant genetic resources and sharing of benefits arising from their utilization. Finally, In fact, Qatar does not have a traditional food insecurity “Lack of access to adequate food during the year due to limited of money”. But food insecurity in Qatar means that Limited resources of biodiversity and agriculture biodiversity resources. As well as it linked to self-sufficiency. Finally, Plant genetic resources provided powerful tools for humanity to control our child's future, and yet not too much been at risk for Qatari genetic resources to be unsustainable, so it is necessary to preserve the natural plant genetic resources on which development is based. Plant genetic resources can be helpful in the achievement of a world without hunger “Food insecurity”.

Wild rice (Zizania palustris) is a naturally-occurring, aquatic plant species that is important to wildlife, aquatic biological systems and humans. Populations of Z. palustris across the geographic range continue to decline in their natural habitat. In some cases, natural populations are being lost. Sometimes referred to as American wild rice, it is genetically similar to Oryza sativa, or cultivated Asian rice. This similarity coupled with modern advances in rice genomics have allowed for comparative genetics and genomics studies between Z. palustris and O. sativa and genetic diversity studies, which have been useful for characterizing the available natural genetic resources. The ongoing wild rice breeding program has been successful in supporting and expanding the cultivated wild rice industry. The incorporation of modern molecular genetics approaches to selection have improved the ability to breed for cultivated wild rice varieties that are more resistant to seed shattering, which has contributed to increased grain production.

PDF HTML阅读 XML下载 导出引用 引用提醒 三疣梭子蟹增养殖过程对野生种群的遗传影响——以海州湾为例 DOI: 10.5846/stxb201208191164 作者: 作者单位: 淮海工学院江苏省海洋生物技术重点实验室,淮海工学院江苏省海洋生物技术重点实验室 作者简介: 通讯作者: 中图分类号: 基金项目: 国家“十二五”科技支撑计划重大资助项目（2011BAD138B03）；国家自然科学基金资助项目（31072213）；江苏省海洋生物技术开放基金资助项目（2006HS002）；江苏省科技支撑计划资助项目（BE2013370）；江苏高校优势学科建设工程资助项目 Genetic impact of swimming crab Portunus trituberculatus farming on wild genetic resources in Haizhou Bay Author: Affiliation: Huaihai Institute of Technology, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为探明三疣梭子蟹人工增殖与养殖活动对野生资源的遗传影响，利用20对SSR引物对海州湾三疣梭子蟹野生群体与两个养殖群体进行群体遗传结构和遗传分化研究。结果表明，野生种群遗传多样性明显高于养殖群体，其群体杂合度Ho为0.8509，而两个养殖群体的杂合度Ho分别为0.4525和0.5283。海州湾野生三疣梭子蟹的 Ne、Ho、He、PIC均显著高于两个养殖群体（P < 0.05）但两养殖群体的 Ne、Ho、He、PIC均无显著差异（P > 0.05）。以上结果说明海州湾天然三疣梭子蟹群体的遗传多样性显著高于养殖群体。3群体间遗传分化处于中度水平（Fst，0.1085-0.1448），基因流Nm处于1.5-2.0间，野生群体与养殖群体的遗传分化比养殖群体内部之间大，基因流也较养殖群体内部之间要小，表明野生群体与养殖群体存在一定的分化，基因流处于中等程度。因此，当前海州湾天然三疣梭子蟹遗传状况良好，养殖活动和人工增殖放流对天然资源的遗传影响还很有限，这可能与海州湾人工养殖三疣梭子蟹时间较短、人工放流的规模较小、时间较短有关。 Abstract:The swimming crab, Portunus trituberculatus (Crustacea: Decapoda: Brachyura), is a large-sized benthic crab species, which is widely distributed in the coastal waters of China, Japan and Korea. FAO data show the world fishing output to be more than 380000 tons in 2010, while the figure for China alone in 2010 amounted to 350000 tons. As a result of artificial mass propagation and improved stock techniques, the farming output also reached 91,000 tons with a farming area of 30000 hectares in 2010. Therefore, the requirement of assessments and conservations of natural genetic resources has become increasingly urgent. The Haizhou Bay is located in Lianyungang coast, Jiangsu Province of China, and as one of the major fishing grounds. The bay was historically famous for the abundance of swiminng crab, but the crab population has been declining due to the over-exploitation. In order to maintain a sustainable stock, releasing of crab produced in hatcheries has been practiced annually to supplement the wild stocks. A large marine farm for swimming crab were constructed for the releasing exercise surrounding a 1700 hm2 aquculture area in the Haizou Bay. In 2009 only, 5839000 individuals of swimming crab were released to the marine farm. However, these practices can cause genetic contamination to the geographically proximate wild stocks when the interbreeding ouccrs between wild poplutions and the released or escaped crabs raised in hatheries. In order to assess the genetic impact of swimming crab farming and popagation releasing on wild stocks in Haizhou Bay, 20 SSR primers designed in our laboratory were used to genetically differentiate swimming crab wild stocks and cultured stocks in Haizhou bay. There were 30 wild swimming crab samples were caught using a gill net in Haizhou Bay (near to Xiaokou village Ganyu haitou town) and 60 cultured individuals obtained from two cultured stocks from aquacultured facilties in Haizhou Bay in Nov., 2011. The results indicated that the genetic diversity of crab from wild stock was higher than that from cultured stocks. The observed heterozygosity Ho value in wild stock was 0.8509, while that in two cultured stocks only were 0.4525 and 0.5283, respectively. The one-way ANOVA showed that the genetic parameters of Ne, Ho, He and PIC in wild crabs were significantly higher than those in cultured stocks (P < 0.05), but those genetic parameters between two cultured stocks were not significantly different (P > 0.05). The Fst value among these stocks ranged from 0.1085 to 0.1448, which showed a moderately differentiated state. The gene flow Nm ranged from 1.5 to 2.0 and the genetic differentiation state was much significantly higer between the wild stock and cultured stocks than that within cultured stocks. In conclusion, the genetic resource of swimming crab in Haizhou Bay was in a good state, and the impact of swimming crab farming and propagation releasing on the natural genetic resource was not remarkerble which was probably related to short time, scale effects of crab farming and propagation releasing. 参考文献 相似文献 引证文献

A large diversity of fruit crop accessions is maintained at the Latvia State Institute of Fruit- Growing, which consists of modern cultivars, landraces and selections from local breeding programmes, as well as germplasm that has resulted from scientific exchange and co-operation with other institutes. Presently, the germplasm collection comprises 2509 accessions of 17 fruit crops; 676 accessions are designated as national genetic resources. Conservation of germplasm itself has little value without characterisation and further utilisation of the stored plant material. To intensify these activities, DNA-based technologies have been implemented in the characterisation of germplasm. Two main groups of molecular markers have been utilised: non-specific markers and gene-specific (functional) markers, subsequently applicable for Marker Assisted Selection (MAS). Genotyping protocols based on SSR, RAPD and Methylation-sensitive amplification polymorphism (MSAP) markers have been developed for twelve fruit crops for use in plant material identification, True-to-Type verification and evaluation of genetic diversity and internal collection structure. In total, 790 accessions have been genotyped using any of the mentioned markers. These markers have been harmonised with the European cooperative programme for plant genetic resources working group (ECPGR WG) recommended sets to ensure international data exchange. Gene specific molecular markers have been applied to apple and pear (resistance to scab), strawberry (resistance to Gnomonia fragariae), sweet cherries and plums (self-incompatibility).

Modern agriculture depends on a coordinated system to evaluate, introduce, distribute and maintain germplasm, since plant germplasm is the base for a productive agriculture. It is estimated that 90% of the germplasm collections are stored as seeds, of which 40% are cereals. Medicinal plants are particularly difficult to store as seeds, due to the lack of knowledge of their reproduction biology and seed behavior. Besides, there are a large number of important tropical and subtropical medicinal plants species which produce recalcitrant seeds that quickly lose viability and do not survive desiccation, hence conventional seed storage strategies are not possible. There is also a number of other import species that are sterile or do not easily produce seeds, or seeds are highly heterozygous and clonal propagation is preferred to conserve elite genotypes. Although field genebanks provide easy access to conserved material for use, they have a risk of destruction by natural calamities, pest and diseases. For this reason, safety duplicates of the living collections are established using alternate strategies of conservation and it is in this area that biotechnology contributed significantly by providing complementary in vitro conservation options through tissue culture techniques. In vitro conservation also offers other distinct advantages. For example, the material can be maintained in a pathogen-tested state, thereby facilitating safer distribution and germplasm exchange. Further, the cultures are not subject to environmental disturbance. The National Genetic Resources and Biotechnology Research Center (CENARGEN), was created by the Brazilian Organization for Agricultural Research (EMBRAPA), an institution linked to the Ministry of Agriculture, in order to coordinate and organize all activities related to genetic resources in Brazil, including genetic resources of medicinal plants. The in vitro collection of medicinal plants of CENARGEN is constituted by at least 395 accessions of five genus: Mentha (74), Lippia (47), Pfaffia (15), Stevia (16) and Cochlospermum (10). Experiments have shown that in vitro shoot cultures stored at temperature in the range of 18-20°C on half strength Murashige and Skoog medium nutrient with 2% sucrose reduce the plant growth and significantly extend the subculture intervals of accessions to fresh medium. We conclude that this in vitro conservation system can be greatly useful for conservation and exchange of genetic resources of these medicinal plants.

Implementation of Nagoya Protocol on access and benefit-sharing in Peru: Implications for researchers