In this thesis, three separate experiments have been performed on different aspects of the interaction between the causal agent of clubroot, Plasmodiophora brassicae, and its hosts. In the first experiment the pathotype of the P. brassicae single spore isolate, which is currently used to construct a reference genome, has been classified using the ECD bioassay. The disease severity of infected plants was scored according to two different scales and the pathotype was determined according to three previously published guidelines. The results were compared to previous published studies describing the e3 isolate. The life cycle of P. brassicae is not well understood.

Hemp is an ancient cultivated plant that came to Sweden in the 1st to 2nd Century and was particularly interesting for use for food, clothing and building materials. Over time, other applications have been developed for hemp, e.g. in energy and health products. Interesting new uses for hemp continue to be identified and this fascinating plant has incredibly versatile applications.In this project, seed production of industrial hemp in Sweden was studied and evaluated. Five different methods are described, four of which are proven under Swedish conditions.

Abstract The aim of this study was to explore and describe the pupils' thoughts on seed and its development into seedling. Twenty nine Swedish pupils at the age of 7 and 10 years old were interviewed about their knowledge of seeds.It turned out that pupils often have so-called everyday belief to describe the natural science phenomenon by connecting their explanations to phenomena in everyday life to which they are familiar. To describe the process of seed developing into seedling is something that most of the pupils believe to be difficult and this resulted mostly in the answer ?it is growing.? Children have some knowledge about what seeds need in order to germinate but they do not mention the importance of oxygen as a component of seed to be able to germinate and grow. They mean instead that it is sufficient with soil, water and sun.The older pupils, however, are more often than the younger pupils able to connect their reflections to a more scientifically correct description based on terms belonging to the phenomena, though these terms sometimes are wrongly used.

Föryngring av skog är en nödvändig, men kostsam åtgärd och därför är det eftersträvansvärt att hitta en föryngringsmetod som är både kostnadseffektiv och ger en bra föryngring. Ett sätt att få en billigare föryngringsåtgärd är att använda frösådd. Vid en lyckad sådd gör det stora plantuppslaget att plantorna får bra förutsättningar för god kvalitet. Dessa plantor får dessutom bättre rotutveckling och stabilitet än planterade plantor. Användningen av skogssådd är dock begränsad av bl.a.

In this study, pollen contamination (measured by the number of seeds pollinated by pollen not belonging to any of the clones on the seed orchard) is compared between open pollination and isolated pollination environments in a Scots pine (Pinus sylvestris) seed orchard called Västerhus, located outside Önsköldsvik. In this seed orchard a tent experiment is taking place. Skogforsk has built six large tents covering 12-14 trees with each tent. Fertilization patterns were compared between one tree in a tent with a supplementation of pollen from five clones not represented in the tent and another tree of the same clone subject to open pollination outside the tents. By using DNA markers the paternity was determined for 48 seeds from each tree.

In this study, pollen contamination (measured by the number of seeds pollinated by pollen not belonging to any of the clones on the seed orchard) is compared between open pollination and isolated pollination environments in a Scots pine (Pinus sylvestris) seed orchard called Västerhus, located outside Önsköldsvik. In this seed orchard a tent experiment is taking place. Skogforsk has built six large tents covering 12-14 trees with each tent. Fertilization patterns were compared between one tree in a tent with a supplementation of pollen from five clones not represented in the tent and another tree of the same clone subject to open pollination outside the tents. By using DNA markers the paternity was determined for 48 seeds from each tree.

The aim of this thesis is to examine one part of Amazon.coms recommender systems: Similar Items. The purpose is also to show the difficulties with subject access, i. e. to find a similar book to the one you just read; problems with traditional systems versus the usefulness with recommender systems like Amazon.coms Similar Items. Similar Items presents a set, a cluster of related items to a given item based on customers co-purchase.

The demands for higher production yields and better quality materials from the forests are increasing globally. Tree breeding programs are directed to meet the future demands on forests. In order to capture the full benefits from the breeding programs, clonal propagation is necessary. For most conifer species, somatic embryogenesis (SE) is the only available option for large scale clonal propagation of Elite clonal material. For Norway spruce (Picea abies L.

This thesis consider alternatives for heating and cooling planned office buildings at Arlanda airport. The thesis is divided into three parts where the third part is a shorter synthesis of the two first. In the first part the energy demands of the buildings are modelled in a computer program. Two different building models are created, one more conventional and one with good energy properties. The results shows that with proper construction and ventilation systems etc.

Detta projektet syftar till att studera om syntes av katalytisk zeolitfilm på inerta packningsmaterial är möjlig. De packningsmaterial som har studerats sfärer med diametern 6 mm och porösa kroppar, båda dessa packningsmaterial innehåller huvudsakligen Al2O3. De zeoliter som har använts är ZSM-5 och Silkalit-1. Den metod som används för syntes av zeolitfilmen är "the Seed Film Method", för att kunna använda metoden har vissa modifieringar av den skett. Proven har karakteriserats med svepelektronmikroskopi, gasadsorption, röntgendiffraktion, dynamisk ljusspridning och termisk analys.

The aim of this study was to investigate if the hen?s genotype, age and diet affect fat components in egg yolk. The fat components measured were total fat content, phospholipids, cholesterol and the fatty acid profile. This trial involved 12 groups of laying hens housed in 8-hen cages enriched with perches, dust baths and nests. The genotype Lohmann Selected Leghorn (LSL) and the genotype Lohmann Brown (LB)was used.

Det här projektet består av en litteraturstudie på trädformig björk (Betula) i Sverige, samt en studie av glasbjörk (B. pubescens) längs en klimatgradient genom Norra Sverige och Norge. Längs den studerade gradienten skiljer sig vegetationsperiodens längd med över en månad i den kallaste delen av gradienten jämfört med den varmaste. Frön längs gradienten har studerats med avseende på grobarhet före och efter simulerad invintring i syfte att undersöka om det finns trender i grad av frövila och grobarhet längs gradienten. Den simulerade invintringen hade en positiv effekt både på groningshastighet och på andel frön som grodde.

Herbicide resistance is the result of an evolutionary process where a population gradually changes from being susceptible to being resistant to an herbicide. The resistance mechanism is usually a change in the biochemistry of the weed, but in some cases changes in morphology or growth rhythm. The change is caused by random mutations. Two resistance mechanisms are found in black-grass; target site resistance and metabolic resistance.Black-grass is a tufty, winter annual grass weed, which is mainly found in milder climates. Black-grass is a big problem in Southern Europe.

In today's agriculture efficiency and the capacity of tools and machinery are crucial. In this work we investigate whether it is possible to enhance the capacity of sowing by increasing the work speed of seeders, how seed technology affects seed placement, and if there is any difference between two different brands of seeders and their sow techniques. The seeders we have chosen to compare are Väderstad Rapid drill and Amazon Cirrus drill. The tillage capacity of the seeders and their traction power needs were examined as well.Väderstad Rapid and Amazon Cirrus were tested in a randomized block design with four replicates at three different speeds, 8 km/h, 12 km/h and 15 km/h. The seed placement at the different speeds was examined by dividing the seedbed into four different zones from its surface to its bottom.

The plants in the genus Elatine are characteristic for oligo and mesotrophic lakes. This study focuses on Elatine hexandra one of the four species in Sweden. It is stated as vulnerable by the National Environment Agency and a conservation plan with guidelines to preserve the plant in Sweden is under preparation. There have been a few previous studies investigating this plant in other countries but this is the first one for Sweden. The aim of this study was to investigate the distribution, growth and reproduction of E.