Segment-based coancestry,additive relationship and genetic variance within and between the Norwegian and the Swedish Fjord horse populations     

Hanne Fjerdingby Olsen  Saija Tenhunen  Nils Ivar Dolvik  Dag Inge Våge  Gunnar Klemetsdal 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2020,69(1-2):118-126

ABSTRACT

The Fjord horse originates from Norway but forms a global population due to several small populations in foreign countries. There exists no information about the additive relationship and the genetic variance between these subpopulations. By collecting blood samples from Norwegian and Swedish Fjord horses, a sample of 311 Norwegian and 102 Swedish horses gave 485,918 SNPs available for analysis. Their inbreeding coefficients were calculated and compared to the pairwise coancestry and the shared genomic segments. The effective population size was almost similar with the two methods in the Norwegian Fjord horse population (63 and 71), but very different in the Swedish population (269 and 1136) and unprecise due to a much smaller number of observations. The study showed that coancestry from shared genomic segments can be used to estimate additive genetic relationship and genetic variation within and between the global populations of the Fjord horse.  相似文献   

The Climate-Species-Matrix to select tree species for urban habitats considering climate change     

Andreas Roloff  Sandra Korn  Sten Gillner 《Urban Forestry & Urban Greening》2009,8(4):295-308

Two hundred and fifty urban woody species are used in Central European parks and gardens. Based on reliable publications we attempt, for the first time, to extensively classify and assess them with regards to their usability after predicted climate changes. A new Climate-Species-Matrix has been developed for this purpose. In a two-dimensional assessment, four degrees of drought resistance and winter robustness are the decisive criteria. The woody species (divided into trees of more than 10 m in potential height and trees/shrubs of up to 10 m in height) were placed into 16 categories by decreasing tolerance, ranging from 1-1 (very suitable) to 4-4 (very limited usability). For many of these species, as well as many others that are not mentioned in this study, not all questions could be answered. Nonetheless, this categorization provides a sound basis for decisions in planning the use of woody species in cities. This planning process must also include additional criteria, dependent on individual requirements such as, soil parameters, shade resistance, aesthetics, etc. This paper is therefore meant to be a basis for discussion and supplementation for further research.  相似文献   

Effects of Plant and Soil Factors on Growth of Young Apple and Blackcurrant Plants     

Ivar Dencker  Poul Hansen 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(1):73-77

Abstract

Shoot growth as affected by plant size at planting, peat application in the planting hole, pruning, drip-irrigation and, for apple, specific apple replant disease (SARD) was investigated in apple (cv. Elstar) and blackcurrant (cvs Ben Lomond and Ben Nevis), using a multifactorial design. In the first year after planting, peat application and drip-irrigation enhanced shoot growth in both species, with a further interactional increase when both treatments were applied. The extension growth of apple, in contrast to blackcurrant, was positively related to plant size, and the strength of the relationship was distinctly improved when growth conditions were good. Pruning had only small effects on total shoot growth, with a trend towards an increase when growth conditions were poor.  相似文献   

Respiration and growth of a fungus, Mortierella isabellina, in response to grazing by Onychiurus armatus (Collembola)     

Göran Bengtsson  Sten Rundgren 《Soil biology & biochemistry》1983,15(4):469-473

Colonies of the fungus Mortierella isabellina (Oudem) were grazed by the collembolan Onychiurus armatus (Tullb.) for short periods interrupted by incubation without grazing in laboratory experiments. The grazed fungus had a lower respiration than ungrazed when Collembola were present on the mycelium. Fungal respiration was significantly increased with grazing when Collembola were periodically removed from the mycelium. Metal contamination of the substrate increased fungal respiration, regardless of grazing. Length of fungal mycelium was significantly greater in a natural soil in the presence of Collembola but reduced in a metal-polluted soil. Factors that may determine the impact of grazing on fungi are discussed.  相似文献   

Effects of metal pollution on the earthwormdendrobaena rubida (Sav.) in acidified soils     

Göran Bengtsson  Torsten Gunnarsson  Sten Rundgren 《Water, air, and soil pollution》1986,28(3-4):361-383

Survival of adultDendrobaena rubida, cocoon production, cocoon viability, and growth of juveniles were examined in laboratory experiments when the worms were reared in acidified and metal polluted soils. Solutions of Cu, Cd and Pb were added to give total concentrations of 10, 100 and 500 μg g^?1 in soils with a pH of 4.5, 5.5 and 6.5. Adult tissues, hatchlings and cocoons were analyzed for metals. D. rubida survived poorly in soils with low pH, especially in combination with Pb or Cu, which accumulated in seminal vesicles and cerebral ganglion. Cocoon production was halved when pH was lowered from 6.5 to 4.5 and metals reduced the cocoon number even more in the most acid soils. Hatching success was lower than 20 % in acidified soils. In contrast, the number of hatchlings increased when pH decreased and peaked in soils polluted with Cd. While low pH reduced the embryonic development time, metals prolonged it. Juveniles grew slowly and died early at low pH.  相似文献   

Possibilities for Increased Carbon Sequestration through the Implementation of Rational Forest Management in Russia     

Shvidenko  Anatoly  Nilsson  Sten  Roshkov  Vjacheslav 《Water, air, and soil pollution》1997,94(1-2):137-162

Huge areas of the Russian forests suffer from insufficient forest management. A scenario has been developed for an improved management program that would be implemented over the next 40 years. Possible options have been aggregated into three interlinked groups: increase in forest productivity through improvement of the forest conditions and the structure of the Forest Fund, decrease of carbon release by mitigation of disturbance regimes, and improvement of landscape management. One prerequisite in developing this scenario was that the cost of sequestering one ton of carbon should not exceed US$3 (1992 dollar value). In this article a simple model is described to illustrate the following possibilities for increased carbon fixation by improved forest management: large-scale reforestation and afforestation, replacement of stands with low productivity and replacement of so called soft deciduous species and “climax” stands, and implementation of rational silviculture (thinning). The results indicate a potential for an increase in carbon fixation in Russian forest ecosystems of 24.4 Pg over 100 years, after the first year that the actions discussed are implemented. The net sink of carbon was determined to be 16.5 Pg in the “low” estimate and 42.5 Pg in the “high” estimate. There are, however, many uncertainties in the data and there are difficulties in adequately modeling the possibilities for implementation under current conditions in Russia. In spite of these uncertainties, we conclude that there is great potential for economically justified increased carbon fixation through improved forest management in Russia.  相似文献   

Infectious salmon anaemia (ISA) epidemiology in Norway     

Ivar V  gsholm  Hans Olav Djupvik  Finn Victor Willumsen  Anne Marie Tveit  Karl Tangen 《Preventive veterinary medicine》1994,19(3-4):277-290

A case-control study is reported of 57 holdings (holdings in which salmon are raised in sea-water) with infectious salmon anaemia (ISA) and 61 holdings without ISA, together with a follow-up study of the control holdings, during 1988–1990. Generally the identified risk factors implied poor biosecurity since passive transmission (proximity to other ISA holdings) and active transmission (management practices which increased exposure to foreign biological material) were found to be major risk factors. The findings indicated that ISA was spread by infected live salmon or infected biological material i.e. animal waste or discharge from normal operations and slaughter. The findings also indicated that decreased host resistance could be important, but these results could be also be explained by a misclassification bias. Moreover, the findings indicate that a prompt eradication policy and improved biosecurity would be important means of controlling ISA.  相似文献   

Genotype dynamics of Campylobacter jejuni in a broiler flock     

Höök H  Fattah MA  Ericsson H  Vågsholm I  Danielsson-Tham ML 《Veterinary microbiology》2005,106(1-2):109-117

We investigated the genotype diversity and dynamics of Campylobacter in a commercial broiler flock during rearing and slaughter. In total, 220 Campylobacter jejuni isolates collected on four sampling occasions during rearing and from routine sampling during slaughter were subtyped by SmaI macrorestriction and pulsed-field gel electrophoresis, PFGE. Eight different SmaI types were found. During rearing, a subsequent addition of genotypes occurred, with two SmaI types found at 2 weeks of age and six types on the day before slaughter. All types that were detected in more than one isolate were also found on all succeeding sampling occasions, including the slaughter sampling. Two new types were found in the slaughter samples. In two-thirds of the individual birds sampled the day before slaughter, more than one SmaI type were found, although there was a clear tendency for dominance of one type in individual birds. Our results show that multiple genotypes of C. jejuni may be present in a commercial broiler flock during rearing and even in gastrointestinal tracts of individual birds. Both recurring environmental exposure and genetic changes within the population may explain the genotype diversity. Although the distribution of genotypes varied between different sampling occasions, we found no indication that any subtype excluded another during the rearing of the broiler flock.  相似文献   

Holding wild Snow crab,Chionoecetes opilio: effects of stocking density and feeding on survival and injury          下载免费PDF全文

Sten Ivar Siikavuopio  Philip James  Bjørn Ronald Olsen  Tor Evensen  Atle Mortensen  Stein Harris Olsen 《Aquaculture Research》2017,48(4):1590-1595

In this study the effects of different stocking densities on survival, injury and weight of captive male snow crab were examined. The first experiment (I) was carried out in square plastic tanks (700 L) with stocking densities of 100 (L), 150 (M) and 200 kg m^?3 (H) for 30 days. In a second experiment (II) snow crabs were kept at a stocking density of 50 kg m^?3 and were either fed (F) or not fed (S) for the same period of 35 days. The last experiment (III), was carried out with stocking densities of 25 kg m^?3 for 21 days with two groups, one with inactivated claw and one without rubber bands, with three replicates per treatment. In the first experiment mortality (H = 27, M = 26 and L = 36%) and occurrence of injuries (H = 27, M = 20 and L = 16%) were high in all groups. The weight loss during the experimental period was; H = 15.3, M = 10.9 and L = 15.5 g, and was not significant different between the groups. In experiment II the mortality (F = 13% and S = 14%) and injuries were lower (F = 12% and S = 17%). The average weight increased in the fed treatment and decreased in the starved treatments. In the last experiment there was no mortality in any of the groups and the levels of injury were low (5% and 7%). The results show that adult male snow crab cannot be stored at densities equal to or higher than 25 kg m^?3 for 3 weeks without risk of mortality.  相似文献   

Measuring density effects on growth and survival of two size classes of juvenile sea urchins (Strongylocentrotus droebachiensis) held in sea‐based holding systems and impacts on holding system design and management          下载免费PDF全文

Philip James  Sten Ivar Siikavuopio  Tomas Wyatt Reguera 《Aquaculture Research》2017,48(11):5541-5549

Assessing density in intensive sea urchin culture systems by measuring the percentage coverage of available surface area is an effective means of calculating the available space within a holding system, the proximity of the animals in the system to each other and the probable effects of the stocking density. The results of this study show that density plays a critical role in regard to both somatic growth (increase in test diameter measured in millimetres) as well as mortality of juvenile sea urchins ranging in size from 5 mm to 26 mm test diameter (the size range tested in the current experiments). These effects appear to be greater for smaller urchins. The critical percentage coverage densities are in the order of 50%‐60% coverage for juvenile sea urchins, and the authors advise farmers growing Strongylocentrotus droebachiensis to maintain stocking densities below this point and to reduce the stocking densities as and when stocks reach these critical density points. Percentage cover must be constantly monitored as the results from this study indicate that the growth rates of juvenile urchins can alter percentage coverage rapidly and reductions in density may be required as frequently as every 3‐4 months at the early juvenile stage. Holding system design should take these factors into account and incorporate a method of rapidly reducing stocking densities with minimal stress and handling of sea urchin stocks.  相似文献