Genomic selection strategies to improve maternal traits in Norwegian White Sheep     

Marie Lillehammer  Anna K. Sonesson  Gunnar Klemetsdal  Thor Blichfeldt  Theo H. E. Meuwissen 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2020,137(4):384-394

This study tested and compared different implementation strategies for genomic selection for Norwegian White Sheep, aiming to increase genetic gain for maternal traits. These strategies were evaluated for their genetic gain ingrowth, carcass and maternal traits, total genetic gain, a weighted sum of the gain in each trait and rates of inbreeding through a full-scale stochastic simulation. Results showed genomic selection schemes to increase genetic gain for maternal traits but reduced genetic gain for other traits. This could also be obtained by selecting rams for artificial selection at a higher age. Implementation of genomic selection in the current breeding structure increased genetic gain for maternal traits up to 57%, outcompeted by reducing the generation interval for artificial insemination rams from current 3 to 2 years. Then, total genetic gain for maternal traits increased by 65%–77% and total genetic gain by18%–20%, but at increased rates of inbreeding.  相似文献   

Multifunctionality of floodplain landscapes: relating management options to ecosystem services     

Stefan Schindler  Zita Sebesvari  Christian Damm  Katrin Euller  Volker Mauerhofer  Anna Schneidergruber  Marianna Biró  Franz Essl  Róbert Kanka  Sophie G. Lauwaars  Christiane Schulz-Zunkel  Theo van der Sluis  Michaela Kropik  Viktor Gasso  Andreas Krug  Martin T. Pusch  Klaus Peter Zulka  Werner Lazowski  Christa Hainz-Renetzeder  Klaus Henle  Thomas Wrbka 《Landscape Ecology》2014,29(2):229-244

The concept of green infrastructure has been recently taken up by the European Commission for ensuring the provision of ecosystem services (ESS). It aims at the supply of multiple ESS in a given landscape, however, the effects of a full suite of management options on multiple ESS and landscape multifunctionality have rarely been assessed. In this paper we use European floodplain landscapes as example to develop an expert based qualitative conceptual model for the assessment of impacts of landscape scale interventions on multifunctionality. European floodplain landscapes are particularly useful for such approach as they originally provided a high variety and quantity of ESS that has declined due to the strong human impact these landscapes have experienced. We provide an overview of the effects of floodplain management options on landscape multifunctionality by assessing the effects of 38 floodplain management interventions on 21 relevant ESS, as well as on overall ESS supply. We found that restoration and rehabilitation consistently increased the multifunctionality of the landscape by enhancing supply of provisioning, regulation/maintenance, and cultural services. In contrast, conventional technical regulation measures and interventions related to extraction, infrastructure and intensive land use cause decrease in multifunctionality and negative effects for the supply of all three aspects of ESS. The overview of the effects of interventions shall provide guidance for decision makers at multiple governance levels. The presented conceptual model could be effectively applied for other landscapes that have potential for a supply of a high diversity of ESS.  相似文献   

Synthesis and preliminary characterization of a new species (amphidiploid) in Cucumis     

Jin-Feng Chen  Jack Staub  Jeff Adelberg  Stephen Lewis  Beth Kunkle 《Euphytica》2002,123(3):315-322

A successful interspecific hybridization between cucumber (Cucumis sativus L., 2n = 14) and a wild it Cucumis species, C. hystrix Chakr. (2n = 24) was made via embryo rescue. Hybrid plants (2n = 19; 7 from cucumber and 12 from C. hystrix) were sterile, but morphologically uniform. Self-pollination and backcrossing of F₁ hybrid plants to either parent confirmed presence of both male- and female-sterility that were likely caused by lack of homology and improper pairing during meiosis. While the multiple-branching habit, densely brown hairs (on corolla and pistil), orange-yellow corolla, and ovate fruit of F₁ hybrid plants were similar to that of the C. hystrix parent, the appearance of the first pistillate flower was more similar to that of C. sativus parent. The diameter and internode length of the stem, and the shape and size of leaves and flowers were intermediate when compared to the parents. The chromosome number in the hybrid was doubled through somaclonal variation during embryo culture and regeneration process to restore the fertility. Pollen grains were released and fruits with viable seeds matured on fertile, synthetic amphidiploid plants. The results from flow cytometry indicated that, on average, 7.3% of the morphologically unique regenerants had the 4C DNA content of 2.35 pg relative to the 2C DNA content of the original F₁ hybrid at 1.17 pg and, therefore, were likely chromosome-doubled F₁ hybrids (2n = 38). Nutrition alanalysis indicated that the synthetic species had higher protein (0.78%)and mineral (0.35%) content compared to the normal pickling cucumber(0.62% and 0.27%, respectively), and could be considered a new Cucumis crop having a special place in the future agriculture. Preliminarily evaluation indicates that C. hystrix possesses a high level of root-knot nematode resistance, and that this resistance is partially expressed in the interspecific F₁ and chromosome-doubled F₁. This and the fact that the fruit morphology of the fertile amphidiploid differs during the growing season (e.g., short and long fruit) suggest that it could be useful in broadening the germplasm base of cucumber. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Classification of landraces and improved cultivars of hexaploid wheats (Triticum aestivum,T. compactum and T. spelta) grown in the USA and described in 1922     

Anton C. Zeven  Theo J. L. van Hintum 《Euphytica》1991,59(1):33-47

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Science and security: a European view     

Wallimann T 《Science (New York, N.Y.)》2003,301(5632):462-463

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Neuroscience. Cellular interactions in the stem cell niche     

Wurmser AE  Palmer TD  Gage FH 《Science (New York, N.Y.)》2004,304(5675):1253-1255

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Slow fertilization of stickleback eggs: the result of sexual conflict?     

Theo CM Bakker  Marc Zbinden  Joachim G Frommen  Alexander Weiss  Carlo R Largiadèr 《BMC ecology》2006,6(1):7-8

Background  

The fertilization success in sperm competition in externally fertilizing fish depends on number and quality of sperm. The time delay between sequential ejaculations may further influence the outcome of sperm competition. Such a time interval can load the raffle over fertilization if fertilization takes place very fast. Short fertilization times are generally assumed for externally fertilizing fish such as the three-spined stickleback (Gasterosteus aculeatus). In this pair-spawning fish, territorial males often try to steal fertilizations in nests of neighbouring males. This sneaking behaviour causes sperm competition. Sneakers will only get a share of paternity when eggs are not fertilized immediately after sperm release. Contrary to males, females may be interested in multiple paternity of their clutch of eggs. There thus may be a sexual conflict over the speed of fertilization.  相似文献   

Screening for the presence of nematophagous fungi collected from Irish sheep pastures     

Paula Kelly  Barbara Good  J.P. Hanrahan  Richard Fitzpatrick  Theo de Waal 《Veterinary parasitology》2009,165(3-4):345-349

With worldwide development of anthelmintic resistance, alternative approaches to the chemotherapeutic dominant approach for the control of parasitic nematodes in sheep are urgently required. As natural enemies of nematodes, nematophagous fungi offer the exciting possibility of an alternative to the dominant anthelmintic approach for parasite control in ruminants. Permanent sheep pasture harbor a promising array of nematophagous fungi and merits further investigation. One hundred and fifty samples of soil, old and fresh faeces were collected from 10 Irish sheep pastures. The three methods employed for the isolation of nematophagous fungi include the Baermann technique, flotation method and the sprinkling–baiting technique. Twenty-nine nematophagous fungi were observed of which 12 were predacious and 17 were endoparasitic. The most prevalent fungi were Cystopage lateralis, Stylopage hadra, Drechmeria coniospora and Meristacrum asterosperum. Permanent sheep pasture is a good source of nematophagous fungi and hence may harbor potential biological control agents. Monacrosporium cionopaga, Duddingtonia flagrans, D. coniospora and Hirsutella rhoissilensis were detected in fresh faecal samples indicating they may have survived the gastrointestinal tract and therefore a viable option as a biological control agent.  相似文献   

Genetic variation in cucumber (Cucumis sativus L.) as assessed by random amplified polymorphic DNA1     

Thomas Horejsi  Jack E. Staub 《Genetic Resources and Crop Evolution》1999,46(4):337-350

Isozyme and restriction fragment length polymorphisms (RFLPs) have been applied to studies of genetic relationships and germplasm management in cucumber (Cucumis sativus L.). However, isozymes identify relatively few polymorphisms, and RFLPs are technically complex, expensive, and not compatible for the high through-put required for rigorous assessment of this narrow-based germplasm. Since random amplified polymorphic DNA (RAPD) markers do not manifest such shortcomings, a study was conducted in cucumber to examine genetic relationships in diverse germplasm, assess the usefulness of RAPD markers in distinguishing elite accessions, and compare the relative effectiveness of RAPD markers to that of isozyme and RFLP markers. One hundred and eighteen C. sativus accessions were analyzed using variation at 71 RAPD loci (44 mapped and 27 unmapped). Genetic distances among accessions were estimated using the simple matching coefficient complement, and analyzed using multi-dimensional scaling. Each accession had a unique marker profile, indicating that RAPD analysis was useful in genotypic differentiation. Germplasm grouping patterns were consistent with individual accession origins, theoretical dispersal routes and discriminating morphological characters (i.e., sex expression and fruit length to diameter ratio). Although elite accessions were discriminated by RAPD profiling, their genetic distances were relatively small (between 0.01 and 0.58), indicating limited genetic diversity in this germplasm array. Assessment of a subset of the germplasm array using RAPDs resulted in genetic distance measurements more similar to published genetic distance estimates by RFLP markers (Spearman rank correlation, r_s = 0.7–0.8) than estimates by isozyme markers (r_s = 0.4). Data indicate that RAPD markers have utility for analysis of genetic diversity and germplasm management in cucumber.  相似文献   

The impact of European landscape transitions on the provision of landscape services: an explorative study using six cases of rural land change     

Van der Sluis  Theo  Pedroli  Bas  Frederiksen  Pia  Kristensen  Søren B. P.  Busck  Anne Gravsholt  Pavlis  Vangelis  Cosor  Georgia Lavinia 《Landscape Ecology》2019,34(2):307-323

Landscape Ecology - The reasons for recent landscape change in the European countryside are complex and poorly substantiated. Identification of drivers of landscape transition and assessment of the...  相似文献