Knolrot in waterlelie 311058 : invloed bewaartemperatuur op het ontstaan van knolrot 311058-01 : invloed teeltomstandigheden op divers uitgangsmateriaal 311058-02 : invloed droog of drijvend bewaren op het ontstaan van knolrot 311058-03 : diagnose monsters 311058-04

Knolrot in waterlelie is een algemeen voorkomend probleem, dat soms ineens voor veel uitval kan zorgen. Het uitgangsmateriaal is duur en daarnaast is oppotten en uitplanten behoorlijk arbeidsintensief. Ernstige uitval zorgt daarom voor een aanzienlijke kostenpost. Voor bestrijding van knolrot in waterlelie is het allereerst van belang de veroorzaker te vinden. Aanvankelijk werd vermoed dat een bepaalde schimmel verantwoordelijk was voor de ziekte, echter dat bleek niet het geval. Uit het onderzoek kwamen aanwijzingen dat een bacterie mogelijk een rol speelt, maar ook dat kon niet worden aangetoond. Uit de inventarisatie in het project Consultancy (nr. 312000) in 2002/2003 kwam naar voren dat knolrot mogelijk tijdens de bewaring (transport) ontstaat

Beheersing van de meikeverengerling: Fase 1

Meikeverengerlingen vormen een groot probleem voor boomkwekers. Ze veroorzaken veel schade aan de gewassen en zijn niet goed te bestrijden. Daarom werd er in dit onderzoek op verschillende manieren naar oplossingen gezocht, middels kevervangsten, middelenproeven en lokkingsproe

Bladvlekken in zomerbloemen : inventarisatie van schimmels en bacterieën verantwoordelijk voor bladvlekken in zomerbloemen

Het doel van het onderzoek is vast te stellen welke ziekteverwekkers verantwoordelijk zijn voor het ontstaan van bladvlekken in diverse soorten zomerbloemen. PPO verzamelde daarom bladmateriaal bij kwekers in de praktijk en probeerde na te gaan welke schimmels of bacteriën daarbij een rol spelen. In het seizoen 2008 zijn beduidend meer monsters verzameld dan in 2007. Met name in Delphinium hebben bladvlekken voor de nodige problemen gezorgd. Uit het onderzoek in 2008 is duidelijk geworden dat de schimmel Phoma de oorzaak is geweest van de problemen in Delphinium

Beheersing van valse meeldauw in Impatiens

De éénjarige zomerbloeier Impatiens walleriana vormt een belangrijk onderdeel in het assortiment van perkgoed. Ondermeer in 2007 waren er door de natte weersomstandigheden grote problemen met uitval door valse meeldauw in de consumentfase. Hierdoor kwam de vraag of er tijdens de opkweek niet meer preventieve maatregelen genomen kunnen worden om infectie door valse meeldauw onder vochtige omstandigheden te verminderen of te voorkomen. Daarnaast was het onbekend of de besmetting met valse meeldauw op Nederlandse locaties veroorzaakt wordt door één soort of meerdere soorten. In een literatuurstudie is alle beschikbare informatie over valse meeldauw en mogelijkheden voor beheersen/ bestrijding samengeva

Potential contribution of ancient introgression to the evolution of a derived reproductive strategy in ricefishes

Transitions from no parental care to extensive care are costly and involve major changes in life history, behaviour and morphology. Nevertheless, in Sulawesi ricefishes, pelvic brooding evolved from transfer brooding in two distantly related lineages within the genera Adrianichthys and Oryzias, respectively. Females of pelvic brooding species carry their eggs attached to their belly until the fry hatches. Despite their phylogenetic distance, both pelvic brooding lineages share a set of external morphological traits. A recent study found no direct gene flow between pelvic brooding lineages, suggesting independent evolution of the derived reproductive strategy. Convergent evolution can, however, also rely on repeated sorting of pre-existing variation of an admixed ancestral population, especially when subjected to similar external selection pressures. We thus used a multi-species coalescent (MSC) model and D-statistics to identify gene-tree - species-tree incongruencies, to evaluate the evolution of pelvic brooding with respect to inter-specific gene flow not only between pelvic brooding lineages, but between pelvic brooding lineages and other Sulawesi ricefish lineages. We found a general network-like evolution in Sulawesi ricefishes and as previously reported, no gene flow between the pelvic brooding lineages. Instead, we found hybridization between the ancestor of pelvic brooding Oryzias and the common ancestor of the Oryzias species from the Lake Poso area. We further detected signs of introgression within the confidence interval of a quantitative trait locus (QTL) associated with pelvic brooding in O. eversi. Our results hint towards a contribution of ancient standing genetic variation to the evolution of pelvic brooding in Oryzias

Understanding interactions in face-to-face and remote undergraduate science laboratories

This paper reviews the ways in which interactions have been studied, and the findings of such studies, in science education in both face-to-face and remote laboratories. Guided by a systematic selection process, 27 directly relevant articles were analysed based on three categories: the instruments used for measuring interactions, the research findings on student interactions, and the theoretical frameworks used in the studies of student interactions. In face-to-face laboratories, instruments for measuring interactions and the characterisation of the nature of interactions were prominent. For remote laboratories, the analysis of direct interactions was found to be lacking. Instead, studies of remote laboratories were mainly concerned with their practical scope. In addition, it is found that only a limited number of theoretical frameworks have been developed and applied in the research design. Existent theories are summarised and possible theoretical frameworks that may be implemented in studies of interactions in undergraduate laboratories are proposed. Finally, future directions for research on the interrelationship between student interactions and laboratory learning are suggested

Genomic analysis of Sparus aurata reveals the evolutionary dynamics of sex-biased genes in a sequential hermaphrodite fish

Sexual dimorphism is a fascinating subject in evolutionary biology and mostly results from sex-biased expression of genes, which have been shown to evolve faster in gonochoristic species. We report here genome and sex-specific transcriptome sequencing of Sparus aurata, a sequential hermaphrodite fish. Evolutionary comparative analysis reveals that sex-biased genes in S. aurata are similar in number and function, but evolved following strikingly divergent patterns compared with gonochoristic species, showing overall slower rates because of stronger functional constraints. Fast evolution is observed only for highly ovary-biased genes due to female-specific patterns of selection that are related to the peculiar reproduction mode of S. aurata, first maturing as male, then as female. To our knowledge, these findings represent the first genome-wide analysis on sex-biased loci in a hermaphrodite vertebrate species, demonstrating how having two sexes in the same individual profoundly affects the fate of a large set of evolutionarily relevant genes.European Union KBBE.2013.1.2-10 European Community 311920 Fondazione Cassa di Risparmio Padova e Rovigo FCT - Foundation for Science and Technology research grant SPARCOMP under the Call ARISTEIA I of the National Strategic Reference Framework - by the EU 36 Hellenic Republic through the European Social Fundinfo:eu-repo/semantics/publishedVersio

How genomics can help biodiversity conservation

The availability of public genomic resources can greatly assist biodiversity assessment, conservation, and restoration efforts by providing evidence for scientifically informed management decisions. Here we survey the main approaches and applications in biodiversity and conservation genomics, considering practical factors, such as cost, time, prerequisite skills, and current shortcomings of applications. Most approaches perform best in combination with reference genomes from the target species or closely related species. We review case studies to illustrate how reference genomes can facilitate biodiversity research and conservation across the tree of life. We conclude that the time is ripe to view reference genomes as fundamental resources and to integrate their use as a best practice in conservation genomics.info:eu-repo/semantics/publishedVersio

The era of reference genomes in conservation genomics

Progress in genome sequencing now enables the large-scale generation of reference genomes. Various international initiatives aim to generate reference genomes representing global biodiversity. These genomes provide unique insights into genomic diversity and architecture, thereby enabling comprehensive analyses of population and functional genomics, and are expected to revolutionize conservation genomics

The era of reference genomes in conservation genomics

Progress in genome sequencing now enables the large-scale generation of reference genomes. Various international initiatives aim to generate reference genomes representing global biodiversity. These genomes provide unique insights into genomic diversity and architecture, thereby enabling comprehensive analyses of population and functional genomics, and are expected to revolutionize conservation genomics