Search results for "RICU"
showing 10 items of 9347 documents
Gene flow relates to evolutionary divergence among populations at the range margin
2020
Background Morphological differentiation between populations resulting from local adaptations to environmental conditions is likely to be more pronounced in populations with increasing genetic isolation. In a previous study a positive clinal variation in body size was observed in isolated Roesel’s bush-cricket, Metrioptera roeselii, populations, but were absent from populations within a continuous distribution at the same latitudinal range. This observational study inferred that there was a phenotypic effect of gene flow on climate-induced selection in this species. Methods To disentangle genetic versus environmental drivers of population differences in morphology, we measured the size of …
Seasonal and ontogenetic variability in stomach size of Eurasian perch (Perca fluviatilis L.)
2019
Eurasian perch (Perca fluviatilis) were sampled in April, from May to June and at the end of August to test whether the current season (i.e. feeding conditions) affects the fishes’ stomach size (i.e. volume and weight). A wide range of size data were analysed to reveal the relationship between fish size (length and weight) and stomach size. No significant differences in length-specific stomach volume or stomach weight were found in fish sampled at different times of the year. However, there were differences between seasons in the size of the stomach in relation to body weight, as length-specific body weight changes during the year because of the development of gametes and changes in nutriti…
Impact of vector dispersal and host-plant fidelity on the dissemination of an emerging plant pathogen
2012
International audience; Dissemination of vector-transmitted pathogens depend on the survival and dispersal of the vector and the vector's ability to transmit the pathogen, while the host range of vector and pathogen determine the breath of transmission possibilities. In this study, we address how the interaction between dispersal and plant fidelities of a pathogen (stolbur phytoplasma tuf-a) and its vector (Hyalesthes obsoletus: Cixiidae) affect the emergence of the pathogen. Using genetic markers, we analysed the geographic origin and range expansion of both organisms in Western Europe and, specifically, whether the pathogen's dissemination in the northern range is caused by resident vecto…
Stand out from the Crowd: Small-Scale Genetic Structuring in the Endemic Sicilian Pond Turtle
2020
The geographical pattern of genetic diversity was investigated in the endemic Sicilian pond turtle Emys trinacris across its entire distribution range, using 16 microsatellite loci. Overall, 245 specimens of E. trinacris were studied, showing high polymorphic microsatellite loci, with allele numbers ranging from 7 to 30. STRUCTURE and GENELAND analyses showed a noteworthy, geographically based structuring of the studied populations in five well-characterized clusters, supported by a moderate degree of genetic diversity (FST values between 0.075 and 0.160). Possible explanations for the genetic fragmentation observed are provided, where both natural and human-mediated habitat fragmentation o…
Introduction of genotypic effects into Genesys-Rape : the example of height and male sterility
2005
Abstract The aim of this study was to introduce effects of rape genotypes on gene flow between rape populations into the existing GeneSys - Rape model and to simulate the influence of existing rapeseed cultivars on gene flow between rapeseed populations in time and in space. The GeneSys - Rape input variables are the regional field pattern, crop successions, cultivation techniques and genotype of cropped cultivars. The main output variables are, for each year and plot, the number of individuals per square meter and the genotype proportions in the harvest. Results comprised: (1) sensitivity analyses of the model to cultivar characteristics, which showed the importance of pollen emission on g…
Using the GENESYS model quantifying the effect of cropping systems on gene escape from GM rape varieties to evaluate and design cropping systems.
2004
Gene flow in rapeseed is a process taking place both in space and over the years and cannot be studied exclusively by field trials. Consequently, the GENESYS model was developed to quantify the effects of cropping systems on transgene escape from rapeseed crops to rapeseed volunteers in neighbour plots and in the subsequent crops. In the present work, this model was used to evaluate the risk of rape harvest contamination by extraneous genes in various farming systems in case of co-existing GM, conventional and organic crops. When 50 % of the rape varieties in the region were transgenic, the rate of GM seeds in non-GM crop harvests on farms with large fields was lower than the 0.9 % purity t…
Response of soil mites (Acari, Mesostigmata) to long-term Norway spruce plantation along a mountain stream
2018
During the nineteenth and twentieth centuries, coniferous monocultures were introduced, replacing natural broadleaved forests in Central Europe, mainly for economic benefits. In the mountains, Norway spruce [Picea abies (L.) H. Karst] was introduced in large areas previously covered with beech forests and also in natural riverside habitat corridors such as river valleys, despite its negative impact on the soil environment by e.g. organic matter accumulation, decrease of soil pH and changes in C/N ratio. We aimed to check how long-term Norway spruce plantations affect species richness and diversity of soil mites along a mountain river in former mixed and broadleaved forests. The study, based…
Evaluación del índice de pobreza hídrica (WPI) en la cuenca de Borujerd-Dorood (Irán) para reforzar los planes de gestión del territorio
2021
El Índice de Pobreza Hídrica (WPI) se considera, en general, una herramienta simple y clara para evaluar los efectos de factores combinados sobre la escasez de agua y la tensión de los recursos hídricos. En esta investigación, intentamos centrarnos en las problemáticas hídricas en las cabeceras de montaña de la cuenca de Karoon en Irán para analizar el estado de los recursos hídricos. Para este propósito, los datos requeridos se obtuvieron en primer lugar mediante la preparación de un informe de la Autoridad del Agua, la parte Agrícola y la Organización de Agua y Saneamiento del Condado de Borujerd. Luego, se estimó el valor del WPI a escala de subcuenca del río Karoon considerando como rec…
Effects of arbuscular mycorrhizal fungi on Gazania rigens pot plant cultivation in a Mediterranean environment
2018
Herbaceous plants used in island beds and borders need to be rapid growing, high performing and maintaining good visual quality during the growing season. Arbuscular mycorrhizal (AM) fungi application is acquiring interest for its beneficial effects on ornamental bedding plants. Gazania rigens is a herbaceous ornamental plant grown for its large daisy-like flowers. The species thrives in the coastal areas of the Mediterranean region, particularly in the mild climate of southern Italy and Sicily, where performs well in summer bedding schemes in sea side gardens even in dry and windy conditions. The aim of this study was to evaluate the effect of inoculation with Rhizophagus irregularis on se…
Effect of temperature on pollen germination for several Rosaceae species: influence of freezing conservation time on germination patterns
2019
[EN] Between February 2018 and April 2018, flowers were collected from eight Rosaceae species. Flowers were kept in a freezer at -20 degrees C for three freezing times (Treatment 1, two months; Treatment 2, four months; Treatment 3, six months). After extracting pollen, in vitro germination was induced in a culture medium and incubated at six different temperatures for 72 h. The percentage of pollen germination, average pollen tube length and maximum pollen tube length were measured. Pollen germination was maximum for all species between 15 degrees C and 30 degrees C. Cydonia oblonga, Malus sylvestris, Prunus avium, Prunus domestica, Prunus dulcis, Prunus persica and Pyrus communis obtained…