| 1. |
- Albertsson, Johannes
(författare)
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Weed problems and possibilities for their control in salix for biomass
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Weed problems and possibilities for their control in salix for biomassShare Albertsson, Johannes (2012). Weed problems and possibilities for their control in salix for biomass. Alnarp, Sweden. Preview PDF 4066Kb AbstractSalix is a dedicated arable bioenergy crop that is presently grown on 12,000 ha in Sweden. It has probably the best environmental profile among the arable bioenergy crops grown in Sweden partly because neither fungicides nor insecticides are used in the production. However, herbicides are used routinely, because salix plants are very sensitive, especially during the first growing season, to competition from weeds. Hence, to improve the environmental profile of salix even further, alternative weed control methods that complement or for substitute the use of herbicides are desired. Some of these alternatives might be to improve the mechanical weeding techniques, using cover crops, applying herbicides more accurately or to breed for weed competitiveness. The purpose of this introductory paper is therefore to review what is known about weeds in relation to biomass salix. To put this subject into context there will first be a general overview of salix and the current production system.
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| 2. |
- Borrero, Felipe
(författare)
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The chemical ecology of armyworms : from ecology to molecules
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Moths of the genus Spodoptera are economically important pest insects. The necessity to develop novel control strategies which may be included in integrated pest management schemes has led to the study of chemical communication in several species within the genus. The polyphagous nature of most Spodoptera species makes it an interesting model to study the way in which different odor profiles are processed and interpreted by the insect brain and how this reflects upon the behavior and ecological interactions which may be of importance in agricultural systems. As such, armyworms have become a model organism in olfactory insect chemical ecology. Here, I attempt to give an overview of what is known about Spodptera chemical ecology to date and present perspectives and directions for future research.
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| 3. |
- Crespo, Leonardo
(författare)
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Resistance to aphids in wheat : from a plant breeding perspective
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Wheat is one of the main staple foods in the world. Among the many constraints there are for wheat production, aphids cause severe damage by their feeding, and by virus transmission. The current document summarizes the available information regarding wheat resistance to aphids. The text is divided into four sections. The first section “Plant resistance to insects: from a historical perspective” serves as an introduction, where some important factors shaping Plant Resistance to insects as a discipline are presented. The section “Categories of resistance and plant defenses to aphids”, presents the concepts of Plant Resistance to insects, with wheat-aphid examples. The methods to assess the categories of resistance are briefly discussed in this section as well. “Genetic resources for resistance to aphids in wheat”, the third part of the document, is focused on the wheat relatives in which resistance to biotic stresses and to aphids in particular can be found. The aim of this section is to describe the resistance donors in relation to each of the main aphid species that attack wheat. Finally, some aspects on how to improve wheat for resistance to aphids are discussed in the fourth section, “Considerations for wheat breeding”.
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| 4. |
- Figueroa, Ilich
(författare)
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The invasive Mediterranean fruit fly Ceratitis capitata Wied (Diptera; Tephritidae) : life history, ecology, behaviour and its implication in ethological management
- 2017
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The Mediterranean fruit fly, Ceratitis capitata is considered a major pest of fruit production worldwide. It is a highly polyphagous species with big capability to adapt and spread into several different environments, giving it the status of a threating invasive species for fruit production in many countries. C. capitata’s high adaptability is mainly related to its life history, behavior and host location ecology, in which semiochemicals play a major role. Several control strategies have been developed using sexual and feeding attractants in monitoring and mass trapping programs, but little is known about the potential of plant-based compounds. These products, such botanical extracts and essential oils, could affect the behavior of pests like C. capitata. By studying and understanding adults’ host location behavior when exposed to olfactory signals (attractant and repellents), the aim of this research is to explore the potential of odour sources for use in C. capitata control strategies for small and medium scale fruit production in Bolivian valleys. This research includes evaluation of locally available protein-based attractants, screening and evaluation of native plant extracts and essential oils as spatial repellents, investigation of the C. capitata interaction with a local apple variety with potential as a trap-crop, and finally the study of the possibilities of the combined use of those components for use in the field.
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| 5. |
- Ghasemkhani, Marjan
(författare)
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Genetic basis for resistance against fruit tree canker in apple
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Neonectria ditissima (formerly Neonectria galligena, anamorph Cylindrocarpon heteronema) is the causal agent of fruit tree canker which is regarded as a serious economic problem in horticulture. This fungus causes notable damage to apple trees and it is very important in some regions, especially North western Europe, where it can result in death of spur shoots and branches. Although it occurs in a wide range of temperatures, it is associated with wet weather and climate has an important effect on the geographic distribution. The fungus produces conidia and ascospores, both of which are dispersed and cause infection during prolonged periods of rainy weather. Also, spores produced on the infected wood can act as an infection source in the orchards. The fungus can therefore be introduced into new orchards with infected planting material from other orchards or tree nurseries. Chemical and mechanical control like spraying of fungicides, covering wounds with paint, and cutting out infected branches, do not prevent the occurrence of epidemics. Breeding cultivars with a high level of resistance towards canker would be of great help towards the avoidance of this disease. Apple cultivars show variable levels of partial resistance to the fungus, whereas complete resistance has not yet been reported and no major genes have been identified. Therefore, apple genotypes with comparatively high levels of genetically determined partial resistance should be identified for use in apple breeding.
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| 6. |
- Husenov, Bahromiddin
(författare)
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Opportunities in Tajikistan to breed wheat varieties resistant to seed-borne diseases and improved baking quality
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Wheat seed-borne diseases and options for improving baking quality of wheat, as well as the role of genotypes for breeding to achieve high yield and quality are the key issues discussed in this introductory paper. The importance of wheat for Tajikistan and how to achieve food security goals in the country is also elucidated. Wheat seed-borne diseases are caused mostly by fungi. Loose Smut (Ustilago tritici), Common Bunt (Tilletia laevis and T.caries), Karnal Bunt (T.indica), Dwarf Bunt (T.controversa) and Black point (Alternaria spp., Bipolaris sorokiniana etc.) are all seed-borne diseases that are economically and regulatory important for Tajikistan, and these are therefore discussed in detail. The peculiarities of Tajik bread and requirements to the grain quality are also highlighted.
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| 7. |
- Hussain, Abrar
(författare)
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Nutritional and mixing characteristics of organically grown wheat genotypes
- 2009
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The topic of this introductory paper is nutritional and mixing characteristics of organically grown wheat genotypes. Due to large consumption of wheat based products, they are among the main sources in the world of nutrition for human. The wheat grain contains e.g. proteins, carbohydrates, minerals and vitamins. The composition of various compounds in the wheat grain depends upon different factors such as variety, soil, environment, management practice, grain processing and post harvest methods etc. Organic cultivation similarly as other cultivation practices influence amounts of different compounds in the wheat grain. Organic conditions are thought to influence amount of antioxidants and other nutritional compounds in the wheat and is also known to influence bread making quality. Therefore it is important to study those parameters of different wheat varieties grown under organic conditions. This review paper is also discussing the mixing behavior of organically grown wheat being important in determining bread making quality
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| 8. |
- Karlsson, Miriam Frida
(författare)
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Odours, potato and insects : host finding and reproduction behaviour
- 2010
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Plant odours can give important information about the specie and these emitted chemical messengers mediate host-finding behaviour, to the insects living on potato. During the development of the potato crop, lasting approximately tree months, the insects described in this paper, has to find the crop. They then chose a part of the potato; leaves, tubers or flowers, where they feed, hide, mate or oviposit. Host plant selection or host preference is not only governed by nutritional quality but also by environmental factors and reproduction success. The synergistic effect of odours from conspecifics and plants can enhance the attractiveness and hence the survival of the specie. Pheromone and kairomone response from two Coleopterans, tree Lepidoptera and two Homopteran insects, that are severe pest on potato, are here described as well as their behaviour towards potato crop. Knowledge about their response to semiochemicals gives indications of how to develop future crop protection management. The enhancement of sex attraction induced by host odors suggests that more effective traps can be devised for management of insect pests
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| 9. |
- Malik, Ali Hafeez
(författare)
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Nutrient uptake, transport and translocation in cereals: influences of environmental and farming conditions
- 2009
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Rapport (populärvet., debatt m.m.)abstract
- The main emphasis of the introductory paper is to highlight the importance of nutrients, their uptake, transport, translocation and use efficiency in cereal crop production. Among the cereals, mainly wheat and barley are discussed in details. Among the nutrients, nitrogen, as one of the most important nutrients, is most deeply described in this paper. Quantitative and qualitative aspects of proteins in wheat and barley are also described in relation to nutrient availability. Nitrogen mineralization and leaching is discussed for cereal cultivation
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| 10. |
- Mujaju, Claid
(författare)
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Diversity of landraces and wild forms of watermelon (Citrullus lanatus) in southern Africa : a synopsis of the PhD Study
- 2009
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The genus Citrullus, belongs to the Cucurbitaceae family. Among the four species in this genus, a single species Citrullus lanatus (Thunberg) Matsum. & Nakai, commonly known as watermelon, is grown throughout the drought-prone southern Africa as a staple food (edible seeds), a dessert food (edible flesh), and for animal feed. The fruit can be eaten fresh or cooked and the seeds can be roasted. Its uses are however, multifaceted and vary depending on the customs of the humans growing this crop. In addition, the fruit can serve as a source of water, especially in deserts or where drinking water is contaminated. Several morphotypes of watermelon are found in southern Africa. Citrullus lanatus exhibits expansive polymorphism in southern Africa and the species occurs in the following forms: wild populations distributed throughout the country in a wide range of habitat types; sweet watermelon, cooking melon and seed melon landraces of the traditional agrosystems; and possibly introgressed types which are regarded as agronomic weeds. Farmers’ traditional onfarm practices contribute to the maintenance of watermelon landraces, and therefore play a role in nurturing local-level diversity. The wild watermelon is widely distributed in Africa and Asia, but originates from southern Africa occurring naturally in South Africa, Namibia, Botswana, Zimbabwe, Mozambique, Zambia and Malawi. There has been little work on investigating the relationships between wild and cultivated forms, and to study amount and partitioning of genetic variation, to allow for better conservation strategies. This paper therefore is an attempt to summarise the work that has been done so far and the background literature, while providing the scope for the PhD study
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| 11. |
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| 12. |
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| 13. |
- Rahmatov, Mahbubjon
(författare)
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Sources of resistance to yellow rust and stem rust in wheat-alien introgressions
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Wheat is the staple food and the main source of caloric intake in most developing countries, and thereby an important source in order to maintain food security for the growing populations in those countries. Stem rust Puccinia graminis f. sp. tritici, and yellow rust P. striiformis f. sp. tritici of wheat continues to cause severe damage locally and globally, thereby contributing to food insecurity. In this paper biology and taxonomy of stem rust and yellow rust, breeding for resistance, utilization of resistance sources from different gene pools, molecular characterization and genetic dissection of resistance to rusts are discussed.
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| 14. |
- Rasheed, Faiza
(författare)
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Production of sustainable bioplastic materials from wheat gluten proteins
- 2011
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Petroleum-based products are creating a number of environmental problems. Petroleum and oil resources are also threatened to become depleted due to the massive utilization. Therefore, it is important to replace the petroleum-based products with products that are instead derived from renewable resources e.g. the replacement of petro-based plastics with bioplastics can be a good option. Wheat gluten proteins might be a promising solution to use for production of bioplastics. Wheat gluten is a cheap by-product from the bio-ethanol industry, thereby largely available and beside that, these proteins have interesting viscoelastic and thermoplastic properties. Gliadin and glutenin i.e. the two major types of gluten protein and their behavior when used to produce bio-based material are discussed in this paper.
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| 15. |
- Schiebe, Christian
(författare)
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Host choice mechanisms in tree killing bark beetles : an overview of joint knowledge and a suggested model of host choice mechanisms in the European spruce bark beetle
- 2011
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Bark beetles with the capacity to kill and colonize living trees are main pests of coniferous forests around the world. The European spruce bark beetle, Ips typographus, belongs to a group of bark beetles possessing facultative attack patterns. For long periods I. typographus is living in low populations only on seriously weakened hosts. However, following disturbances like storms or drought periods, the amount of suitable breading material increases dramatically and the population size of beetles may rise within a short time to epidemic levels. In the epidemic phase I. typographus behaves aggressively, attacking healthy trees and destroying large areas of Norway spruce forest. Bark beetles with this pattern of behaviour are exploiting a different ecological niche than during the endemic, low population phase: in broken or seriously weakened hosts they exploit a relatively poor source of nutrients without dealing with host defences. Instead they have to deal with a higher degree of interspecific competition. On the other hand, a living host provides breeding material, which is rich in nutrients and relatively free from interspecific competition, but there beetles have to fight the defence responses of the host tree. Host defences can be overcome by mass attack of thousands of beetles on the same tree, which is coordinated by aggregation pheromones. The trade-off between evaluating host quality and risk rating host defences is a great challenge for the pioneering beetles, that initiate an attack before any pheromone plumes exist. The host choice mechanism can be divided in several distinct steps: 1. habitat location during flight 2. host location during flight 3. host evaluation after landing, involving detection of host suitability and spacing between species and individuals to avoid inter- or intraspecific competition. 4. risk rating host defences after entrance into host phloem. The question whether the beetles’ attack behaviour is ruled by pheromone attraction alone or is guided by markers for host suitability has been an issue of debate for decades. The peripheral nervous system of bark beetles possesses olfactory receptor neurons for both pheromones, host volatiles and non-host volatiles. Several studies support the theory that non-host volatiles cues play an important role in habitat location, while host volatiles are involved in host finding and host acceptance, either alone or through modulating pheromone attraction. Host defence responses consist of physical barriers and chemical compounds that may be detrimental to invaders. Conifers maintain a certain level of preformed (constitutive) defence that can be enhanced during and after the attacks, e.g. by the increased production of defensive metabolites and development of defensive structures. The different metabolites involved in a trees defence responses may be important markers for beetles to evaluate the trees’ defensive ability, and guide them in their decision to enter a host. Because the population density is an important factor influencing the beetles’ success in overwhelming a trees defence, it has been hypothesized that it also will modulate beetles behaviour, either directly or through its influence on the beetles’ quality. This introductory paper is written to obtain an overview over the literature dealing with different aspects of host choice in bark beetle species exhibiting so called aggressive host colonisation behaviour. Different hypotheses and aspects of importance for the host choice behaviour are discussed. Finally, I propose a host choice model for the European spruce bark beetle Ips typographus
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| 16. |
- Vagiri, Michael
(författare)
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Black currant (Ribes nigrum L.) - an insight into the crop : a synopsis of a phd study
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- There is an increasing interest in the inclusion of berries, especially the black currant in the human diet mainly for the health benefits associated with their consumption. Black currant (Ribes nigrum L.) belonging to the genus Ribes is widely cultivated across temperate Europe, Russia, New Zealand, parts of Asia and to a lesser extent North America. Besides high content of tasty juice, black currant is a valuable source of bioactive compounds like vitamin C and polyphenols, acting as antioxidants, with a potential to protect against disorders such as cardiovascular events, cancer and other degenerative symptoms. Industrially, black currant fruits are considered to be of importance; however other anatomical parts like buds and leaves are also excellent sources of phenolic compounds. The leaf and bud extracts are of relevance as raw material for the food and health industry thereby making black currant a lucrative product for use as functional food ingredient. Research until now has investigated the content of different polyphenolic fractions of the fruits and to lesser extent on content of these fractions on plant parts like buds and leaves. The breeding of black currant is mainly focussed on national and international requirements, as related to specific quality desired from the processing sector alongside with important agronomic characters. Black currant cultivation is in different areas limited by a lack of climate adaptation in the existing cultivars as well as susceptibility of these cultivars to different pests and diseases. Also, the levels of bioactive compounds in black currant like content of ascorbic acid and polyphenols are influenced by genotype, environment and genotype x environment interactions. Durable resistance towards damaging pest and diseases together with an increase in content of health promoting compounds and adaptability to local climates remain to be of high priority for breeders. Additionally flavour, mouth feel, aroma and after taste are important primary quality factors for the fresh fruit market and juice industry. This introductory paper focuses on the history of development and biology of black currant; their ecology and environmental adaptability; crop utilisation; bioactive compounds, genetic, biochemical and phenotypic diversity. The breeding objectives and important pest and diseases are also presented. This paper is an attempt to review important work that has been done so far and the background literature, whilst providing the scope for the current PhD study
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| 17. |
- Zubair, Muhammad
(författare)
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Genetic and environmental effects on polyphenols in Plantago major
- 2010
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Leaves and seeds of Plantago major (common plantain or greater plantain) have been used for centuries to treat diseases relating to skin, digestive organs and blood circulation like wounds, inflammation and hypertension. Either whole or crushed leaves have been used to treat for example burns and all kinds of wounds to enhance the healing process, and to stop bleeding. To treat superficial wounds it is sufficient to apply the juice from the leaves. Both polysaccharides and polyphenols may have a synergistic effect on wound healing and other biological activities. Polyphenols extracted from leaves and seeds of P. major have been reported to have bioactive effects especially on wound healing, and to have antiulcerogenic, anti-inflammatory, antioxidant, anticarcinogenic and antiviral activity. Three subspecies have been described of P. major, two of which have been subjected to genetic and phytochemical analysis. Plantago major subsp. major is naturalized almost throughout the world and is mainly found as an agronomic weed. There has been little work emphasizing the utilization of the bioactive compounds from P. major in modern medicine. Similarly, the effects of genetic and environmental factors on the occurrence of these bioactive compounds have not been reported. The main emphasis of the introductor y paper is to highlight some factors that may be important for the utilization of Plantago major as a medicinal herb, providing the scope for the Ph.D. study. This paper also describes the taxonomy including morphological differences between the two subspecies, distribution, biology, genetics and DNA markers used in P. major
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