| 1. |
- Handlin, Linda
(författare)
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Human-Human and Human-Animal Interaction : Some Common Physiological and Psychological Effects
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of the present thesis was to investigate hormonal and physiological effects in mothers during a breastfeeding session and in dogs and their owners in response to short-term interaction. In study one, sixty-six mothers receiving either exogenous oxytocin infusion and/or epidural analgesia (EDA) during labor or intramuscular oxytocin injection post partum were studied. Oxytocin, prolactin, adrenocorticotrophic hormone (ACTH) and cortisol levels, as well as blood pressure were measured during a breastfeeding session two days after birth. In response to breastfeeding two days after birth, the mothers displayed a pulsatile release of oxytocin and increasing prolactin levels. In addition, the activity in the HPA-axis was reduced and maternal blood pressure decreased. The results also show that EDA administration in combination with oxytocin during labor resulted insignificantly lower oxytocin levels and higher cortisol levels, as well as higher bloodpressure in response to breastfeeding two days after birth, compared to EDA administration alone. In addition, oxytocin infusions dose-dependently lowered the mothers’ endogenous oxytocin levels two days after birth. In study two, ten female dog owners and their male Labrador dogs participated, together with ten controls. Their levels of oxytocin, cortisol and insulin, as well as their heart rate, were measured. The connection between the quality of the dogowner relationship and hormone levels was also explored. Short-term interaction between dogs and their owners resulted in oxytocin release in both species and their cortisol levels and heart rate were also affected. Oxytocin levels and positive attitudes regarding the dog-owner relationship were positively correlated. In conclusion, both human-human and human-animal interactions induce oxytocin release and promote oxytocin mediated effects, such as decreasing cortisol levels and blood pressure. In addition, social interaction and oxytocin levels arepositively related.
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| 2. |
- Söderquist, Pär
(författare)
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Large-scale releases of native species : the mallard as a predictive model system
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Human alteration of natural systems, and its consequences are of great concern and the impact on global ecosystems is one of the biggest threats that biodiversity stands before. Translocations of invasive species, as well as intraspecific contingents with non-native genotypes, whether they are deliberate or unintentional, are one such alteration and its consequences are continuously being assessed. The mallard (Anas platyrhynchos) is the most numerous and widespread duck in the world and a flagship in wetland conservation. It is also an important game species which is heavily restocked for hunting purposes, especially in Europe where over three million ducklings are released every year. Because of its hunted status, its abundance, and the number of released individuals, it can serve as a model species to study effects of releases, both for conservation and restocking for hunting, on wild populations. In this thesis the status of the mallard was assessed in the Nordic countries and the effects of releases on the wild populations were studied by mining historical ringing data, comparing morphology of present-day wild, farmed, and historical mallards, and analyzing phylogeography of wild and farmed mallards in Europe. The status of the mallard population in the Nordic countries are generally good, however, a joint effort of European countries is needed to monitor and manage the population. A significant difference between wild and farmed mallards concerning longevity, migration, bill morphology and genetic structure was also found, together with signs of cryptic introgression of farmed genotypes in the wild population with potential fitness reduction as a result. The effect is however limited by that only a fraction of released farmed mallards reach the breeding season due to low survival. A natural captive environment is crucial to keep individuals wild-like with high survival rates after release. However, with an introgression of potentially maladapted farmed genotypes leading to a reduction in fitness, a low survival of released mallards would favor the wild population. A legislative change regarding obligation to report numbers, provenance, and release sites of farmed mallard should be considered, together with practical solutions of ringing and genetic monitoring of released mallards.
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| 3. |
- Montelius, Malin
(författare)
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Chlorine Cycling in Terrestrial Environments
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Chlorinated organic compounds (Clorg) are produced naturally in soil. Formation and degradation of Clorg affect the chlorine (Cl) cycling in terrestrial environments and chlorine can be retained or released from soil. Cl is known to have the same behaviour as radioactive chlorine-36 (36Cl), a long-lived radioisotope with a half-life of 300,000 years. 36Cl attracts interest because of its presence in radioactive waste, making 36Cl a potential risk for humans and animals due to possible biological uptake. This thesis studies the distribution and cycling of chloride (Cl–) and Clorg in terrestrial environments by using laboratory controlled soil incubation studies and a forest field study. The results show higher amounts of Cl– and Clorg and higher chlorination rates in coniferous forest soils than in pasture and agricultural soils. Tree species is the most important factor regulating Cl– and Clorg levels, whereas geographical location, atmospheric deposition, and soil type are less important. The root zone was the most active site of the chlorination process. Moreover, this thesis confirms that bulk Clorg dechlorination rates are similar to, or higher than, chlorination rates and that there are at least two major Clorg pools, one being dechlorinated quickly and one remarkably slower. While chlorination rates were negatively influenced by nitrogen additions, dechlorination rates, seem unaffected by nitrogen. The results implicate that Cl cycling is highly active in soils and Cl– and Clorg levels result from a dynamic equilibrium between chlorination and dechlorination. Influence of tree species and the rapid and slow cycling of some Cl pools, are critical to consider in studies of Cl in terrestrial environments. This information can be used to better understand Cl in risk-assessment modelling including inorganic and organic 36Cl.
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| 4. |
- Felleki, Majbritt
(författare)
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Genetic Heteroscedasticity for Domestic Animal Traits
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Animal traits differ not only in mean, but also in variation around the mean. For instance, one sire’s daughter group may be very homogeneous, while another sire’s daughters are much more heterogeneous in performance. The difference in residual variance can partially be explained by genetic differences. Models for such genetic heterogeneity of environmental variance include genetic effects for the mean and residual variance, and a correlation between the genetic effects for the mean and residual variance to measure how the residual variance might vary with the mean.The aim of this thesis was to develop a method based on double hierarchical generalized linear models for estimating genetic heteroscedasticity, and to apply it on four traits in two domestic animal species; teat count and litter size in pigs, and milk production and somatic cell count in dairy cows.The method developed is fast and has been implemented in software that is widely used in animal breeding, which makes it convenient to use. It is based on an approximation of double hierarchical generalized linear models by normal distributions. When having repeated observations on individuals or genetic groups, the estimates were found to be unbiased.For the traits studied, the estimated heritability values for the mean and the residual variance, and the genetic coefficients of variation, were found in the usual ranges reported. The genetic correlation between mean and residual variance was estimated for the pig traits only, and was found to be favorable for litter size, but unfavorable for teat count.
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| 5. |
- Abubaker, Jamal
(författare)
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Effects of fertilisation with biogas residues on crop yield, soil microbiology and greenhouse gas emissions : recycling of plant nutrients from bioenergy production
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The amount of residues generated by biogas production has increased dramatically due to worldwide interest in using renewable energy. Biogas residues (BRs) originate from anaerobic degradation of different types of rural and urban organic wastes and have been proposed as organic fertilisers because of their high content of ammonium and other valuable macro- and micro-nutrients. However, application of BRs to agricultural soils may be accompanied by environmental risks, since they may contain heavy metals and organic pollutants. Therefore the effects of BRs on crop production and on the soil ecosystem and environment urgently need to be investigated before their wider use. This thesis evaluated and compared different types of BRs against cattle slurry, pig slurry, compost and mineral fertiliser with respect to their (1) ability to provide plants with necessary nutrients, (2) impact on the soil microbial ecosystem and (3) effects on emissions of the greenhouse gas nitrous oxide (N₂O). The results from short-term laboratory experiments and a long-term field trial showed that BRs increased crop yield to the same extent or more than conventional mineral fertiliser and compost, but less than pig slurry. BRs generated from source-separated organic household waste had a tendency to give higher crop yield and soil microbial activities than other BRs. BRs had no general negative effect on soil respiration, but substrate-induced respiration decreased significantly in organic soil on addition of BRs. Although all BRs initially inhibited potential ammonium oxidation and potential denitrification activity, no long-term negative effects were detected. BRs stimulated ammonium assimilation, which can temporarily decrease nitrogen availability to the plant. Furthermore, the bacterial community structure in the sandy soil was altered by BRs and cattle slurry, but no significant change was seen in the community structure of clay and organic soil. Application of BRs and animal slurry increased N₂O emissions, but the total losses and flux patterns were affected by fertiliser type and soil type. In conclusion, the fertiliser value of BRs should be regarded as high and they apparently have no long-term adverse effects on soil microbial functions and structures. Thus the problematic amounts of residues associated with expansion of biogas production could be turned to advantage, as these residues seem to be safe and competitive fertilisers.
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| 6. |
- Ahmadi Afzadi, Masoud
(författare)
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Genetic variation in resistance to fungal storage diseases in apple : inoculation-based screening, transcriptomics and biochemistry
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Apple is one of the economically and culturally most important fruit crops and has many health-related benefits. Apple production is, however, sensitive to several fungal diseases including blue mold, caused by Penicillium expansum. Problems are more pronounced in organic production or in countries where postharvest application of fungicides is prohibited. To limit or overcome this problem, many studies have been focused on investigations of the mechanism of resistance/tolerance. No major gene(s) have as yet been identified, but quantitatively inherited traits, some of which are related to fruit texture and content of chemical compounds, have been shown to affect the ability of cultivars to withstand storage diseases. In the present thesis, inter-cultivar variation in terms of resistance to fungal storage diseases was investigated at two locations, i.e. Balsgård in Sweden and Njøs in Norway. The association of harvest date, fruit firmness and softening with lesion decay was investigated on large sets of cultivars. The contribution of four fruit texture-related genes (Md-ACO1, Md-ACS1, Md-Exp7 and Md-PG1) in explaining the fruit texture characteristics was examined. Fruit content of chemical compounds with a potential impact on disease resistance was also investigated, and finally the regulation of apple genes upon fungal infection was studied in order to identify candidate genes responsible for disease resistance. Inoculation-based screening indicated large variation across the investigated cultivars in terms of blue mold and bitter rot susceptibility. Harvest date and softening rate of fruits during storage had a large impact on resistance to fungal diseases, thus cultivars with moderate to firm fruits that soften comparatively little during storage could withstand the fungal infection comparatively well. Softening rate is, in its turn, closely associated with harvest date whereas four fruit texture-related genes had lower predictive power than expected. Quantifying the chemical compounds in the fruit samples revealed that some of these compounds, especially flavonols and procyanidin B2, could contribute to resistance against blue mold, whereas contents of malic acids or total titratable acidity had considerably less impact. Differential expression of FLS, LDOX, and CHS genes involved in biosynthesis of flavonoids and PGIP, TT10, WAK1 and CTL1 genes related to cell wall structure indicate the importance of fruit characteristics and biochemical compounds in the resistance mechanism.
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| 7. |
- Alam, Mehboob
(författare)
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Microbial status of irrigation water for vegetables as affected by cultural practices : agronomic aspects
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Human pathogens present in irrigation water can be transmitted to plants. Consumption of fruits and vegetables irrigated with pathogen-contaminated water can cause illness in humans. Leafy vegetables that are consumed fresh are particularly prone to cause such illnesses. Understanding the microbiota of irrigation water and its decontamination and introducing some preventative pre-harvest cultural practices can help procure hygienically safe horticultural produce. Variations were found in water indicator organisms, including heterotrophic plate counts, total coliforms, thermotolerant coliforms, Escherichia coli and faecal enterococci, at five different sampling sites in an irrigation water distribution system (IWDS) on a commercial vegetable-growing farm. 454-pyrosequencing data showed that the IWDS bacterial community was dominated by Bacteriodetes and Proteobacteria, with classes within these phyla, including Flavobacteriia, Sphingobacteriia, α-, β- and γ-Proteobacteria, being found at all five sampling sites. The genera Arcicella, Flavobacterium, Limnohabitans, Sejongia, Fluviicola, Escherichia, Clostridium and Legionella were present at various sites. Indicator organisms and the pathogen Salmonella in the IWDS were significantly reduced by photocatalytic treatment in most cases. Pre-harvest cultural practices to reduce pathogen load, including cessation of irrigation with contaminated water three days before harvest and decreasing the water regime of the growing medium for leafy vegetables, were assessed. The results showed that an attenuated gfp-tagged E. coli O157:H7 decreased with increasing time to harvest after cessation of irrigation, but were present in the plant phyllosphere three days after cessation, irrespective of dose applied. Similarly, both attenuated gfp-tagged E. coli O157:H7 and an attenuated strain of L. monocytogenes persisted in vegetables grown at a reduced water regime in the growing medium. Total microbiota and Enterobacteriaceae remained unchanged on plants after cessation of irrigation with contaminated water and on plants grown on different water regimes. Use of contaminated irrigation water for leafy vegetable production should thus be avoided. Photocatalytic treatment can be used to decontaminate irrigation water.
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| 8. |
- Ali, Liaqat
(författare)
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Pre-harvest factors affecting quality and shelf-life in raspberries and blackberries (Rubus spp. L.)
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Fruit including berries have been demonstrated to exhibit a broad spectrum of benefits including protection against cardiovascular, neurological, and lung diseases, as well as having antioxidant, antimicrobial, anti-inflammatory, anti- diabetic and anti-aging properties. These protective effects are reported to be due to their high content of bioactive compounds, such as vitamin C, vitamin E, phenolic acids, ellagitannins, flavonoids and carotenoids. This thesis investigated the effect of pre- and postharvest factors on the concentrations of bioactive compounds in raspberries and blackberries. The factors studied included genetic variability, organic and synthetic fertilizers, seasonal variation (harvest-to-harvest and annual variation) in greenhouse, high tunnel and open field production, and post-harvest storage. Concentrations of bioactive compounds (anthocyanins, vitamin C, ellagic acid, carotenoids) in the berries, or in the leaves, were quantitatively analysed by high-performance liquid chromatography, and total phenolics were analysed by a spectrophotometric method. Generative parameters (yield, fruit size) investigated for the cultivar difference and organic nitrogen, responded differently to the nitrogen level within cultivars and varied significantly in primocane raspberries. Taste compounds, such as total acidity and different sugars, varied during the season and with nutrient regimes. Time of harvest also affected the ellagic acid content, which was high in early season, and the vitamin C content, which was high in late season in primocane raspberries. Significant changes were also found between different years. Vitamin C decreased significantly with high synthetic N and with low K application, but the application of high N with high K showed positive influence in the level of nutrients and bioactive compounds in blackberries except for ellagic acid. Increased level of organic fertilization (12-17 g N/plant) in primocane raspberries caused only minor changes in the analysed compounds. The post-harvest performance of raspberries regarding the levels of bioactive compounds was less dynamic than in blackberries. In addition, raspberries harvested in late season showed comparatively less changes in sugar content during storage as compared to early harvest, indicating less enzymatic activity in the late season.
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| 9. |
- Andersson, Helena
(författare)
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The role of subsoil properties for phosphorus leaching in agricultural soils
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Phosphorus (P) leaching from agricultural land is a large contributor to eutrophication of many surface waters and the Baltic Sea. Better knowledge of P sorption and release in the subsoil could enable the development of effective mitigation strategies for P leaching. This thesis examined the impact of soil properties on P leaching from four Swedish agricultural soils (two clays, two sands), using intact soil columns extracted with (length 1.05 m) and without (length 0.77 m) topsoil. The role of the subsoil as a source or sink for P leaching was also investigated, and placement of quicklime (CaO) on top of the subsoil as a mitigation strategy for P leaching was evaluated. Leaching of dissolved reactive P (DRP) from subsoil lysimeters was 94% of that from full-length lysimeters in one of the clay soils, and 70% in the other. The higher contribution of the former clay subsoil was probably due to high P content deeper in the soil. Leaching of DRP was low from full-length and subsoil lysimeters (0.12 and 0.08 kg ha-1 yr-1, respectively) in one of the sandy soils, despite high topsoil P content, due to high P sorption capacity and low degree of P saturation in the subsoil. However, leaching of DRP was very high from full-length and subsoil lysimeters (3.33 and 3.29 kg ha-1 yr-1, respectively) from the other sandy soil with moderate topsoil P content, due to high P content and low P sorption capacity in the subsoil. These results indicate that the subsoil can function as both a source and sink for P leaching. Phosphorus leaching increased with increasing P content and DPS in subsoil and decreasing P sorption capacity in topsoil and subsoil, indicating that these parameters could be used for P leaching risk assessments. However, on soils with preferential flow in the subsoil, P leaching may be high despite high subsoil P sorption capacity. Hence, both chemical and physical properties of topsoil and subsoil must be considered in implementation of appropriate, cost-effective mitigation strategies for P loss reductions. Application of lime on top of the subsoil significantly reduced leaching of particulate P (PP) in both clay subsoils by 49 and 51%, respectively, compared with unlimed controls. This suggests that subsoil liming might be an appropriate method to reduce P leaching from clay soils.
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| 10. |
- Calleja-Rodriguez, Ainhoa
(författare)
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Quantitative Genetics and Genomic Selection of Scots pine
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The final objective of tree improvement programs is to increase the frequency of favourable alleles in a population, for the traits of interest within the breeding programs. To achieve this, it is crucial to decompose the phenotypic variance accurately into its genetic and environmental components in order to obtain a precise estimation of genetic parameters and to increase genetic gains. The overall aim of this thesis was to increase the accuracy of genetic parameter estimation by incorporating new quantitative genetics models to the analysis of multiple traits in multiple trials of Scots pine, and to develop a genomic selection protocol to accelerate genetic gain. Factor analysis was incorporated to multivariate multi-environment analyses and it allowed to evaluate up to 19 traits simultaneously. As a result, precise patterns of genotype-by-environment interactions (G E) were observed for tree vitality and height; moreover, it was possible to detect the main driver of the G E: differences in temperature sum among sites. Traditional quantitative trait loci (QTL) analysis of phenotypic data was compared with the detection of QTL with estimated breeding values (EBV) for the first time in a three generation pedigree and, as outcome, it was noticed that if a QTL was associated to a EBV and to a phenotypic trait, the proportion of variance explained by the QTLEBV was higher than the QTL-phenotype. Additionally, several QTL were detected across several ages, which may make them suitable as candidates for early selection. Genomic selection (GS) could aid to reduce the breeding cycle by shortening the periods of progeny field testing, and consequently increasing genetic gains per year. Genomic predictions, including additive and non-additive effects through different prediction models were compared with traditional pedigree-based models; it was seen an overestimation of genetic parameters for pedigree-based models, even larger when nonadditive effects could not be discerned from additive and residual effects. Prediction accuracies and abilities of the genomic models were sufficient to achieve higher selection efficiencies and responses per year varying between 50-90% by shortening 50% the breeding cycle. For the selection of the top 50 individuals, higher gains were estimated if non-additive effects are incorporated to the models (7 – 117%).
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| 11. |
- Cuevas Romero, Julieta Sandra
(författare)
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Studies of the molecular genetics and epidemiology of porcine rubulavirus infection
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Porcine rubulavirus (PorPV) infection emerged spontaneously in pigs in Mexico in the early 1980s. Since the report of the initial outbreak of the disease, only one full-length genome from a strain isolated in 1984 (PorPV-LPMV/1984) has been sequenced. There is therefore limited information about the genetic variation of this virus. The overall objective of this thesis was to develop molecular techniques to help in the diagnostic field and to investigate in greater detail the full genomes of several isolates, and if possible, gain insights into the persistence, molecular epidemiology and the possible reservoirs of PorPV. In addition, a characterisation of the immune response during acute and persistent infection was included. A real-time RT-PCR was developed for the detection of viral RNA from PorPV in clinical samples using TaqMan technology and primers for the P gene. This assay was highly sensitive (approximately 10 copies per reaction), specific, reproducible and a very useful tool for molecular diagnostics and for enabling studies of various aspects of PorPV throughout this thesis. RT-PCRs based on the NP and P genes were used to study the tissue distribution of the virus. Viral mRNA in the lymph nodes showed that the NP gene was consistently detected in the parotid, submaxilar, cervical and mesenteric nodes and the pancreas. Full-length genomes were sequenced from new isolates obtained from clinical cases of infected swine. The genetic comparison and phylogenetic analysis indicated that three different genetic variants of PorPV had spread in the swine population and that a new generation of circulating virus with a pronounced attenuation has begun to emerge in nature. We also report the isolation of PorPV, or a related virus, from frugivorous, insectivorous, and hematophagous bats. A partial genome sequence analysis showed a 99.97 - 100% amino acid identity to the reference strain isolated from swine. However, larger parts of the genome must be sequenced to ascertain the genetic relationship between these viruses. The study of the immune response during acute and persistent infection revealed enhanced levels of CD8+, CD4+ and CD2+ T-cells in all infected pigs at 10 days PI. CD8+ T-cell subpopulations were significantly higher (p<0.05) at 10 and 250 days PI, and CD4+ T-lymphocytes were also significant at 250 days PI. In summary, this work developed molecular techniques that can be used to study the pathogenesis and molecular epidemiology of PorPV. The knowledge of the presence of different virus variants in nature, associated with a wildlife reservoir of PorPV can provide greater knowledge regarding the molecular genetic changes and useful data to establish new strategies in the control of this virus in Mexico.
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| 12. |
- Fundová, Irena
(författare)
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Quantitative genetics of wood quality traits in Scots pine
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Wood quality of commercial tree species is important for many wood processingindustries and thus should be considered for inclusion in forest tree improvementprograms. This thesis evaluated the suitability of various proxy methods for rapid andnon-destructive assessment of wood quality traits on standing trees of Scots pine and thepotential for genetic improvement of different wood quality traits through recurrentselective breeding.Penetrometer Pilodyn and micro-drill Resistograph were tested for non-destructiveassessment of wood density (DENPIL and DENRES, respectively), using SilviScan density(DENSILV) as a benchmark. A strong additive genetic correlation was observed betweenDENSILV and DENRES (rA = 0.96), whilst the correlation with DENPIL was substantiallylower (rA = 0.74). Furthermore, SilviScan stiffness (MOESILV) was used as a benchmarkfor evaluation of several approaches of calculating the dynamic modulus of elasticity(MOE) from standing-tree acoustic velocity (VELTREE). The combination of VELTREEand adjusted DENRES provided the most accurate estimate of MOETREE (rA = 0.91).Additionally, non-destructive acoustic sensing tools were tested at different stages ofwood processing (on standing trees, felled logs and sawn boards) using destructivelymeasured sawn-board stiffness (static modulus of elasticity, MOES) and strength(modulus of rupture, MOR) as benchmarks. They proved to be capable of accuratelypredicting MOES (rA ≈ 0.8) while VELTREE, adjusted DENRES and MOETREE wellreflected MOR (rA ≈ 0.9). Genetic variation of shape stability of sawn boards (bow, crookand twist) was also investigated. Under-bark grain angle (GRA) was found to be a goodpredictor of sawn-board twisting and crooking (rA = 0.84 and 0.62, respectively). Thechemical composition of juvenile wood (proportion of cellulose, hemicelluloses, ligninand extractives) was predicted from Fourier transform infrared (FTIR) spectra usingpartial least squares regression (PLSR) modeling. Individual-tree narrow-senseheritabilities (ℎi2) for all of the studied wood quality traits varied from low to moderate.Genetic improvement of sawn-board DEN, MOES and MOR as the target traits couldbe achieved through selective breeding for MOETREE, DENRES, stem straightness (STR)or GRA. Selection focusing on GRA would also result in lower bow, crook and twist.Despite the negative genetic correlations between growth and wood quality traits, apossibility of their simultaneous improvement was identified. An index combining stemdiameter (DBH) and MOETREE provided the best compromise.
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| 13. |
- Henriksson, Maria
(författare)
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Greenhouse gas emissions from Swedish milk production : towards climate-smart milk production
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Greenhouse gas (GHG) emissions from food production represent 19-29% of global anthropogenic GHG and the dairy sector alone is estimated to contribute around 3%. This thesis assessed GHG estimates for milk production (i.e. milk carbon footprint (CF)) in a life cycle perspective. Uncertainties in milk CF were examined for two contrasting milk production systems (an intensive system in Sweden (SE) and a more extensive system in New Zealand (NZ)) and variations in milk CF estimates between Swedish dairy farms were determined. GHG emissions from feed production and enteric fermentation, representing around 85% of milk CF, were estimated on herd level for different feeding strategies related to regional conditions for feed cultivation. The methodology used was Life Cycle Assessment with the system boundary 'cradle to farm gate'. National average milk CF for SE and NZ was estimated to be 1.16 and 1.00 kg carbon dioxide equivalents (CO₂e)/kg energy corrected milk (ECM) respectively, with uncertainty of approximately ±30% due to uncertainties in emissions factors predicting enteric CH₄ and soil N₂O emissions, which were among the most influential parameters for milk CF estimates. The most influential variable was feed intake. Milk CF was found to vary by approximately ±17% between Swedish dairy farms due to differences in management practices, indicating potential for reducing GHG emissions on farm level. GHG emissions from different feeding strategies varied between 0.42 and 0.53 kg CO₂e/kg ECM for feed production, and between 0.50 and 0.52 kg CO₂e/kg ECM for corresponding enteric CH₄. Thus differences in feeding strategy affected GHG emissions from feed production more than enteric CH₄ production. Roughage production contributed >50% of the emissions and grass silage CF varied markedly (by 17%) between regions and influenced the overall emissions. It was also influenced by feed losses from silage storage and feeding. Grass silage nutrient quality also influenced emissions from feed production and enteric CH₄ production. Replacement animals contributed approximately 20% of these GHG. The large uncertainties in milk CF indicate that values should not be compared unless estimated with harmonised methods and that caution is needed when they are used in mitigation studies. Efficient use of all resources is an important general mitigation measure. Measures with varying effects need to be evaluated at farm level.
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| 14. |
- Hu, Jia
(författare)
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Climate-friendly rice - characterisation of rice varieties associated with low-methane emissions and improved bioenergy properties
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Paddy rice cultivation contributes to global warming by emitting methane into the atmosphere. The aims of the work presented in this thesis were to breed climatefriendly rice varieties, to increase rice straw utilisation to reduce the impact of rice cultivation on the environment. The results showed that fumarate and ethanol were the two major exudate compounds from SUSIBA2-rice roots regulating methane emissions from SUSIBA2-rice paddies. A naturally occurring low-methane rice variety was identified and field testing demonstrated that it could be successfully grown in Uppsala, Sweden, opening up possibilities for expanding rice cultivation into high-latitude countries. Key candidate genes important in adaptation of rice to Scandinavian light and climate conditions were identified. By crossing a naturally occurring low-methane rice variety with four high-yielding elite varieties, four independent lines of low-methane rice with high yield potential were developed. Field trials demonstrated that methane emissions from the selected lines were reduced by 70%. Analysis of carbon allocation and molecular analyses of gene activities revealed that sugar transporters such as SUT and SWEET participated in allocation of carbon to aboveground tissues, contributing to the high yield and lowmethane properties. The results also indicated that increasing the lipid content in rice straw could increase its value in bioenergy production. Overall, this thesis shows that plant breeding can successfully address several pressing issues affecting sustainability in rice production by reducing greenhouse gas emissions, increasing crop productivity and diversity, and improving bioenergy production from straw.
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| 15. |
- Hussain, Abrar
(författare)
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Quality of organically produced wheat from diverse origin
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The health benefits of organically grown whole grain wheat are derived from various nutritional compounds such as dietary fibre, minerals, vitamins and phytochemicals, while baking quality is influenced by the protein content and composition. Genetic improvement and production of wheat to increase the amounts of the nutritional compounds therefore enhance the health benefits. Also, the baking quality of organic wheat can be improved by increasing protein quality of the grain. This study screened a large collection of organically grown winter and spring wheat genotypes from six groups (selections, old landraces, primitive wheat, spelt, old cultivars and cultivars) for different nutritionally relevant compounds such as, minerals, tocochromanols (vitamin E) and heavy metals. The genotypes were also screened for protein quality related to bread-making performance. There was a wide variation in grain concentrations of minerals, total tocochromanols, heavy metals and protein fractions between the six genotype groups, indicating that there is a great potential to use genotypes for the production and the development of specific wheat genotypes with health-promoting and bread-making properties for future breeding programmes. Primitive wheat had higher amounts of most minerals studied, a higher percentage of tocotrienols in total tocochromanols (74%) and a lower amount of cadmium in the wheat grain than the other genotype groups. Around 70% of the recommended daily intake (RDI) of most minerals and up to 24% of the RDI of vitamin E could be obtained by consuming the organically produced whole grain wheat genotypes tested. Tocochromanol content and vitamin E activity are known to be lowered by heating, so organically produced wheat might be a good source of minerals and tocochromanols since organically produced wheat is more commonly consumed as whole or sprouted grain as compared to conventionally produced wheat. There was also a wide variation in the amount and size distribution of polymeric proteins (ASPP), mixing parameters and structural properties between the six genotype groups investigated. Genotypes with a high protein concentration and a high percentage of unextractable polymeric proteins in total polymeric proteins (%UPP) might be helpful in improving the bread-making quality of organic wheat.
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| 16. |
- Högberg, Niclas
(författare)
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Sensing the worms : automated behaviour monitoring for detection of parasitism in grazing livestock
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Gastrointestinal nematodes (GIN) are common in grazing livestock and is a major cause of impaired health and productivity. Current control practices of GIN infections depend largely on the use of anthelmintic drugs. However, misuse of anthelmintic drugs has led to a widespread development of anthelmintic resistance. Behavioural monitoring has been suggested as a novel method to detect parasite infection in grazing livestock, enabling targeted (selective) treatment, where only infected groups or individual animals within a group are treated. The aim of this thesis was to investigate how multispecies GIN parasite infections affect behavioural patterns in grazing livestock on a group level using different on-animal sensors. The effect of subclinical GIN infection on activity and rumination patterns in first season grazing steers were investigated in contrasting groups during two grazing seasons, using different commercial sensors. The results indicate that untreated steers exposed to a higher GIN level had an increased lying time, lower activity level and affected rumination patterns over time, compared with dewormed steers. To enable the assessment of behavioural responses in lambs, the validity of two sensors for cattle for use in lambs were first evaluated. The effect of subclinical GIN infection on activity in lambs around weaning was then investigated in a replicated grazing trial with treated and untreated groups. The results indicate untreated lambs had a shorter daily lying time over time as well as a lower activity level, compared with dewormed lambs. In conclusion, this thesis supports that behavioural patterns are affected by subclinical GIN infections and the results demonstrate the potential use of automated behavioural observations as a diagnostic tool.
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| 17. |
- Höjer, Annika
(författare)
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Phytoestrogens and fatty acids in forage and bovine milk
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The overall aims of the studies underlying this thesis were to investigate effects of key factors on the concentrations and composition of phytoestrogens and fatty acids in forage species, and effects of differences in their concentrations and composition in forage on their concentrations in bovine milk. In each of the spring cuts, the total isoflavone concentrations in red clover were higher at Umeå than at Skara. At Umeå, the concentration decreased with later cutting time, but at Skara there were no differences between the cutting times. The most abundant isoflavone found in red clover were formononetin, followed by biochanin A. In the summer cuts, the total isoflavone concentration decreased with a longer regrowth interval at Umeå, but this variable was not affected at Skara. Concentrations of each of the analysed isoflavones were considerably higher in red clover than in birdsfoot trefoil. Secoisolariciresinol was only found in birdsfoot trefoil. Meadow fescue had in general higher concentrations fatty acids than timothy. The concentrations of all fatty acids in the grasses decreased with increasing lateness of cutting time in spring cuts. In general, concentrations of C18:0 and C18:1 were higher and concentrations of C16:0, C18:3 and total fatty acids lower in red clover than in birdsfoot trefoil. The concentration of almost all fatty acids decreased with later cutting time. There were correlations between leaf blade proportions, α-tocopherol, β-carotene and protein concentrations, and the fatty acid concentrations. Two similar silage feeding experiments were conducted in which dairy cows were fed silage mixtures. In both experiments, the concentrations of all isoflavones were higher and those of mammalian lignans lower in milk from cows on the red clover-grass diets than in milk from cows on the birdsfoot trefoil-grass or white clover-grass diets. However, the largest observed difference in milk phytoestrogen contents was in the equol concentration. For the fatty acids, the proportions in the milk and recoveries of C18:2n-6 and C18:3n-3 were higher on the red clover diets than on birdsfoot trefoil-grass or white clover-grass diets. Shortening the regrowth interval increased the proportion of unsaturated fatty acids in milk. Supplementation with α-tocopherol increased milk α-tocopherol concentrations but did not affect milk fatty acid composition.
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| 18. |
- Karlsson, Frida
(författare)
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Treponema spp. in porcine skin ulcers : clinical aspects
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The hypothesis tested in this work is that bacteria of genus Treponema play a main role when shoulder ulcers and ear necrosis occur in an infectious or severe form, and perhaps also in other skin conditions in the pig. Samples were collected from pigs in 19 Swedish herds 2010-2011. The sampled skin lesions included 52 shoulder ulcers, 57 ear necroses, 4 facial necroses and 5 other skin ulcers. Occurrence of spirochetes was detected by phase contrast microscopy, Warthin-Starry silver staining, PCR and Fluorescent In Situ Hybridization (FISH). Treponemal diversity was investigated by sequencing of 16S-23S rRNA intergenic spacer region 2 (ISR2) and high-throughput sequencing (HTS) of a part of the 16S rRNA gene. Culturing and characterization of treponemes by biochemical analyses, testing of antimicrobial susceptibility and fingerprinting by random amplified polymorphic DNA (RAPD) were carried out. A challenge study was performed to test if Treponema pedis induced skin lesions. Serological response towards TPE0673, a T. pedis protein, was tested with ELISA. Spirochetes were found in all types of skin ulcers and in all herds. The occurrence of Treponema spp. detected by PCR was 52% in shoulder ulcers, 46% in ear necrosis and 9.7% in gingiva. Treponemes were identified in 69% of the shoulder ulcers and in 59% of the ear necroses by FISH. A phylogenetic tree revealed a great variability of treponemes. Three main phylotypes were identified; T. pedis, Treponema parvum and one phylotype without designation. Twelve isolates of T. pedis, T. parvum, and one phylotype most similar to Treponema sp. OMZ 840 were obtained. All except two had unique RAPD fingerprints. Biochemical tests could not differentiate between the isolates and they were generally susceptible to tested antimicrobials. By FISH, treponemes were visualized deep in the ulcers and a predominance of T. pedis was noted, and confirmed by HTS. Challenged pigs did not develop any lesions or IgG response towards the T. pedis protein. Most sows with shoulder ulcers showed a strong, and most cases of ear necrosis a weak IgG response towards TPE0673. In conclusion, Treponema spp. are frequently abundant in ear necroses and shoulder ulcers in pigs. Identical phylotypes and ISR2 sequences from ulcers and gingiva indicate spreading from mouth to ulcer. A broad diversity of phylotypes was revealed, but the predominance of T. pedis suggests specific importance of this species. Our results point towards an important role of treponemes in chronic and severe skin ulcers in pigs.
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| 19. |
- Leonova, Svetlana
(författare)
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Lipids in seeds of oat (Avena spp.), a potential oil crop : content, quality, metabolism, and possibilities for improvement
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- New oil crops with high yield and oil content are urgently needed. Oat is the only cereal that accumulates substantial amount of lipids in the endosperm. This gives it potential as an oil crop, which could address both nutritional and environmental concerns of modern society. To develop oat with increased oil content, thorough investigations on its lipid metabolism and tools for genetic manipulations are needed. Analyses of lipids in seeds of wild and cultivated oat species revealed variation in wild oat accessions in both oil content and quality. This variation should allow for development of new oat varieties for diverse applications. However, to develop oat as an oil crop, a level of 20% of the seed dry weight as oil is required and the range of oil content in the studied accessions was 4-10%. Another feature which showed almost no deviation was the amount of omega 3 fatty acid, -linolenic acid (0.6-2.1%). To develop oat varieties with ultra-high seed oil and increased content of omega 3 fatty acids, a biotechnological approach is preferred to conventional breeding methods. Lipids in oat endosperm have been reported to exist, not enclosed in oil bodies, but as non-structured oil smear. In my study, I also observed oil smears, a phenomenon probably correlated with the reduced amount of oil body associated proteins in the endosperm, as revealed by microscopic and staining methods. This was supported experimentally by SDS-PAGE separation of oil-body proteins and immunoblotting and immunolocalization with antibodies against a 16 kD oil body protein. Biochemical studies on lipid mobilization during oat seed germination demonstrated efficient utilization of oil reserves from the starchy endosperm; these results were corroborated by microscopy. An oat cultivar which is capable of accumulating high amounts of oil in the endosperm was shown to be also efficient in utilizing these reserves upon germination. Agrobacterium-mediated transformation is one of the methods for modification of oat oil content and/or its quality. The results of the analyses aimed at development of an Agrobacterium-mediated oat transformation protocol are presented in this thesis.
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| 20. |
- Lv, Yanrong
(författare)
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Triterpenes and phenolic compounds in apple fruit (Malus domestica Borkh.) : variation due to cultivar, sun exposure, rootstock, harvest maturity, bruising, fungi inoculation, ozone treatment and storage conditions
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Apple (Malus × domestica Borkh.), a popular and widely cultivated fruit world-wide, contains bioactive triterpenes and phenolic compounds with potentially valuable pharmacological functions. This thesis investigated the effects of pre-harvest and postharvest factors on concentrations of these bioactive compounds in apples. It also studied the effect of ozone treatment, before or during storage, combined with cold storage on triterpene and phenolic compound concentrations in apples and the antifungal activity of triterpene-enriched crude extract. Concentrations of two major triterpenes, oleanolic acid and ursolic acid, in apple peel varied significantly between cultivars, with the late-ripening cultivar ‘Gloster’ having higher concentrations than the earlier ripening ‘Discovery’ and ‘Aroma’. The concentrations were higher in peel from the shaded side than from the sun-exposed side of both ‘Discovery’ and ‘Gloster’ apples. Harvest time and storage methods had minor effects on the concentrations, although some between-cultivar variation was observed. Inoculation with Penicillium expansum decreased oleanolic acid concentration in ‘Discovery’ and ‘Gloster’ at harvest in one study year and decreased ursolic acid concentration in ‘Aroma’ after cold storage. Oleanolic acid and ursolic acid concentrations in apple peel showed non-consistent changes in different cultivars after bruising. On four of six harvest occasions during a two-year study of ‘Aroma’, the concentrations were higher in peel of apples from rootstock ‘MM106’ than from ‘M9’. Total polyphenolics concentration was higher in ‘Amorosa’ peel than in ‘Santana’ peel at harvest and after four months of storage. Ursolic acid concentration in apple peel was almost unaffected by ozone treatment, but oleanolic acid concentration showed differing responses to varying ozone application. The concentrations of different bioactive compounds both increased and decreased after ozone treatment, but the changes were within the range of fluctuations observed in untreated apples during storage. Low-dose ozone treatment (0.5 ppm gaseous ozone one hour per day) during four months of cold storage did not affect total polyphenolics in ‘Amorosa’ and ‘Santana’ flesh, but increased total polyphenolics in ‘Amorosa’ peel and decreased them in ‘Santana’. Short-term ozone treatment (2.5 ppm gaseous ozone and ozonated water, alone or combined) before one month of cold storage reduced total polyphenolics content in apple peel, while inconsistent responses were observed in apple flesh. Triterpene-enriched water significantly inhibited mycelial growth of all pathogens studied, but inhibited conidia production differently in each pathogen.
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| 21. |
- Maggioni, Lorenzo
(författare)
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Domestication of Brassica oleracea L.
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Various theories exist about the progenitors of B. oleracea L. (cole crops) and the area of its domestication. Relatively recent molecular data have pointed at the wild species growing on the European Atlantic cliffs as the closest relatives to all the cultivated types. Compatibly with all the existing observations, an alternative hypothesis is formulated here, namely that the domestication of B. oleracea occurred in a Mediterranean location, while the crop reached the Atlantic coast only at a later date, with the movement of people and cultures. The wild Atlantic populations are supposed to be re-naturalized escapes from the fields. If this theory could be confirmed, it would be plausible for all the cole crops to show the highest affinity with the Atlantic populations, since these belonged to the same genetic pool that underwent a domestication bottleneck. Our experimental work revolved around attempts to test the above-mentioned hypothesis through indirect means. Linguistic, literary and historical aspects of the use of cole crops indicate a deep-rooted knowledge and use of cole crops as well as of their wild relatives by the ancient Greek and Roman civilizations. Moreover, words used to name the coles throughout Europe largely if not exclusively derive from Greek or Latin roots. Analysis of the genetic diversity of leafy kales from around Europe did not find a geographic pattern and a directionality. Agro-ecosystems mimicking a situation of initial domestication, with cole crops and one of their wild relatives (B. rupestris Raf.) growing in close proximity to one another were analysed. Patterns of gene flow have been identified and domestication scenarios have been described. Evidence of populations of coles escaping from the field and becoming indistinguishable from truly wild populations was obtained with molecular marker studies. Finally, attention was given to the legal aspects of collecting wild specimens of genetic resources in Europe, with an analysis and discussion about this issue. This work analyses strengths and weaknesses of the existing theories of domestication of B. oleracea and supports an alternative and original hypothesis that will deserve to be further tested in future before a conclusive statement can be made on the origin of the coles.
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| 22. |
- Malik, Ali Hafeez
(författare)
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Governing grain protein concentration and composition in wheat and barley : use of genetic and environmental factors
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- For commercial production of wheat and barley, grain yield (GY), grain protein concentration (GPC) and protein composition are considered important. Genetic (G) and environmental (E) factors are important constraints affecting GPC and protein composition in wheat and barley. This thesis examined the options to govern GPC and protein composition in wheat and barley grain by using G and E factors. The results showed that combination of G and E factors played an important role, more important than single factors solely, to determine GPC, protein composition, accumulation and protein breakdown in wheat and barley grains. Differences in maturation times of wheat and barley plants, due to variation in G and E factors, were found to be a significant factor in determining GPC and protein composition. By governing the maturation times, using different genotypes, N application rates and timings, pre- and post-anthesis temperature, the options to govern GPC and protein composition increased. Early maturing cultivars, N application at anthesis and high pre-anthesis temperature resulted in high amounts of sodium dodecyl sulphate (SDS)-extractable proteins (TOTE). Late maturing cultivars, N application at spike formation and high post-anthesis temperature resulted in high percentage of SDS- unextractable polymers into total polymers (%UPP). Pre-anthesis temperature influenced mainly TOTE, while post-anthesis temperature influenced mainly %UPP. Maturation time was found more important for determining GPC and protein composition at high temperature while at low temperature late nitrogen supply was of higher relevance. Differences in the build-up of TOTE and polymeric proteins were found to initiate from 12 days after anthesis and thereafter the build-up rate pertained throughout the grain maturation period. In barley, breakdown of proteins at malting were found dependent on plant maturation time and GPC i.e. higher breakdown rate at higher GPC. A negative correlation was found between GY and TOTE and between TOTE and %UPP. The results from this thesis help to understand how GPC, protein composition, accumulation and breakdown are governed in wheat and barley by various G and E factors. Moreover, the results may help in creating a simulation based quality model in which both G and E factors can be used to model GPC and protein composition in wheat and barley.
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| 23. |
- Nemesio Gorriz, Miguel
(författare)
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Molecular responses against Heterobasidion annosum s.l. in Picea abies
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Norway spruce [Picea abies (L.) Karst.] is a main tree species in European forests and is important both ecologically and economically. The root rot fungus Heterobasidion annosum sensu lato (s.l.) is the main P. abies pathogen. Including resistance in breeding programs would help mitigating the impact of the pathogen but knowledge regarding defense mechanisms in P. abies needs a better understanding. The work within this thesis intended to expand the existing knowledge on P. abies resistance mechanisms focusing on hormone signaling, flavonoid biosynthesis and its transcriptional regulation. I found that jasmonic acid is the major hormone controlling defense signaling pathways in P. abies. Furthermore, we validated a candidate gene, PaLAR3, as a resistance marker for H. annosum s.l. in P. abies. PaLAR3 encodes an enzyme responsible for the synthesis of (+) catechin, which showed a fungistatic effect on H. parviporum. Analysis of genetic diversity revealed two allelic lineages of PaLAR3 that showed significant differences in fungal resistance and (+) catechin content that were explained by dissimilarities in inducibility. We studied the role of PaNAC03, a transcription factor that is associated with H. annosum s.l. infection. PaNAC03 not only showed repression of multiple genes including PaLAR3, but bound only to the promoter of one of the PaLAR3 allelic lineages explaining at least partly the differences in allelic expression that were observed. Finally, we identified a full repertoire of members of a MYB/bHLH/WDR transcription factor complex in Norway spruce, which showed differences in protein interactions and expression patterns, and also in ability to control the expression of genes in the flavonoid biosynthetic pathway including PaLAR3.
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| 24. |
- Nur, Ahmed
(författare)
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Pesticide use in periurban areas : farmers’ and neighbours’ perceptions and attitudes, and agricultural field influences on pests in nearby garden plants
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Public concern about pesticide use is very high, although it varies with social, ethical and political factors. In periurban regions, farmers live close to people with other occupations. Thus farming activities such as pesticide spraying may cause tensions. Pesticide use may also cause changes in pest abundances outside the treated field, on plants in neighbouring gardens. The first part of this thesis compared perceptions of pesticide use by farmers and their neighbours in two periurban regions in Sweden. Neighbours reported using pesticides, but perceived pesticide use to be more negative than farmers did. Neighbours also perceived themselves as pesticide non-users to a higher extent than farmers, although both categories used pesticides in their home setting to a similar extent. Perceptions of pesticide use differed between farmers and neighbours but also between groups of farmers, depending on farm size, whether pesticides were used or not, number of crops grown and pesticide safety knowledge. In two field studies, abundances of pests were compared in garden crops adjacent to insecticide-treated and untreated agricultural fields. The garden crops were not subjected to wind drift during insecticide spraying. Despite this, pest abundance and their damage on vegetables and ornamental flowers in nearby gardens decreased with insecticide use in the agricultural fields. The magnitude of this decrease depended on type of insect pests targeted, garden plants tested and timing of pesticide applications. In general, perceptions and attitudes concerning pesticide use differed between groups of people in the periurban society studied, e.g. with social factors such as gender, age and education. The fact that pesticide use in agricultural fields may actually benefit neighbouring garden crops is a novel finding. The findings presented here can be of use for policy makers to avoid conflicts regarding pesticide use in periurban environments, since it is important to address variations in the views of different groups of people in society and to communicate both the negative and positive effects of pesticide use.
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| 25. |
- Oyewole, Olusegun Ayodeji
(författare)
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Soil nitrogen fluxes and root uptake in the boreal forest : key processes to plant nitrogen nutrition
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Nitrogen (N) is essential for growth and net primary production of plants. However, N acquisition by plants is influenced by movement of soil N compounds from bulk soil to plant roots and uptake of N by roots. This thesis is aimed at deepening our knowledge on these key processes involved in plant N acquisition in the N-limited boreal forest. To address this aim, a novel, non-invasive microdialysis technique was employed. Amino acids dominated N fluxes in the boreal forest soils. Further, plant roots were shown to have the capacity to absorb organic and inorganic N present in the measured soil fluxes, but these soil fluxes, rather than root uptake, may limit plant N acquisition. The microdialysis technique was further developed to enable simultaneous estimation of diffusion and mass flow of N in soil. Applying this refinement of the technique in the field showed that mass flow significantly increased flux rates of soil N in the boreal forest ecosystem, and that it also altered the chemical composition of the N fluxes. The results from the studies presented in this thesis highlight the potential of the microdialysis technique to improve our understanding of the intrinsic processes involved in N acquisition by plant roots. They also suggest that amino acids might comprise an important source of N for plants in the boreal forest ecosystem. The results suggest that mass flow plays an important role for plant N acquisition in the boreal forest, and mass flow might increase the share of nitrate, particularly in nutrient-rich ecosystems. This finding opens a discussion on the role of transpiration in plant N nutrition, with implications for our understanding of how plant N nutrition will be affected by, among other things, elevated CO2, increased temperatures, and N fertilization.
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| 26. |
- Parvage, Masud
(författare)
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Impact of horse-keeping on phosphorus (P) concentrations in soil and water
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Agricultural sources contribute significantly to the high phosphorus (P) loads in water, causing eutrophication in many of Europe’s water bodies. Consequently, priority has been given to reducing P leakage from sources, including soils used for animal farming. Horse farms use about 4 % of the total agricultural land in the EU, but have not so far been investigated thoroughly with regard to their impact on water quality. This study characterised the potential risk of P leaching losses from Swedish horse paddocks in a three-stage investigation of the soil and water P status. The study began with an analysis of eight years of drainage P data from a small catchment, a so called – ‘observation field’, dominated by horse paddocks (Paper I). In the following study (Paper II), soil P status was examined in different parts of the horse paddocks (feeding, grazing and excretion areas) to identify potential hotspots for high P losses within the paddock. In the third experiment (Paper III), topsoil columns (0 - 20 cm) from different segments of the paddock (feeding, grazing, and excretion area) were isolated and potential leaching losses of P from the soil columns were measured during simulated rainfall in the laboratory. The studies showed that: i) horse paddocks can pose a potential threat to water quality via leaching of excess P, ii) feeding and excretion areas are potential hotspots for significantly high leaching losses, and iii) paddocks established on sandy soils are particularly vulnerable to high P losses. Besides identifying P leaching problems, additional investigations were carried out to mitigate P losses from paddocks using organic bedding materials (e.g. wheat straw, wood chips and peat) (Paper IV) and to determine an environmentally safe load of horse manure for arable soils (Paper V). The main findings of these studies were: iv) of the three bedding materials, only wood chips could reduce P losses while the other two enhanced leaching losses, and v) the addition of composted horse manure up to 36 Mg ha-1 (22 kg P ha-1) did not increase P leaching from organic soil, but from the mineral soils, while 90 - 100 % of the added P from the compost was retained in the soils. Finally, proposals for better paddock management were outlined and the need for national rules/regulations for horse paddocks were stressed to avoid nutrient build-up and to reduce losses. In addition, to strengthen the understandings and conclusions, more field studies were suggested for future research.
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| 27. |
- Persson, Sara
(författare)
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The wild male mink as a sentinel for endocrine-disrupting chemicals and reproductive toxicity
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Increasing evidence indicates that pollutants may affect the hormone system of humans and wildlife. These endocrine-disrupting chemicals are related to an increased risk of a variety of diseases and disorders, including adverse effects on the reproductive system. By using a sentinel wildlife species, an early warning of adverse health effects due to pollutants in the environment may be provided. This is also relevant for humans, as wildlife and humans can be exposed to similar mixtures of pollutants. With this in mind, the aim of this thesis is to investigate the possibility of establishing the wild mink (Neovison vison) as a sentinel species in Sweden, for both exposure to pollutants and effects of pollutants on the reproductive system. Mink were collected from local hunters and necropsies were performed focusing on the male reproductive system. The collected mink provided an insight in how to handle the variation in data due to sample season, age and nutritional status. These factors significantly influenced many, but not all, of the concentrations of chlorinated, brominated and perfluorinated compounds and also some reproductive organ variables. In addition, the results offer information on how to optimize the design of future studies, and some baseline data for reproductive organ measurements were compiled. Considerable concentrations of PCBs were found in some areas and the concentrations of PFOS were among the highest ever recorded in mink. Associations were found between measurements on the reproductive organs and pollutant concentrations. The anogenital distance was inversely associated with concentrations of some perfluoroalkyl acids and DDE. Several associations were also found between some PCB congeners and measurements on the penis and baculum. In conclusion, the wild mink males may serve as an indicator for environmental exposure to pollutants in Sweden. In addition, the wild mink seems to be a suitable sentinel species that may provide an early warning of alterations in the male reproductive organs related to environmental pollution.
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| 28. |
- Pham, Toan Duc
(författare)
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Analyses of genetic diversity and desirable traits in sesame (Sesamum indicum L., Pedaliaceae) : implication for breeding and conservation
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Sesame (Sesamum indicum L., Pedaliaceae) is a traditional oil crop cultivated in Vietnam and Cambodia. It is known as the king of oil seeds in Vietnam due to the high oil content (50-60%) in its seed. Yet, the insufficient genetic information regarding Vietnamese and Cambodian sesame populations is limiting the access to useful traits present among adapted landraces in this region. The purpose of this study was to characterize various sesame accessions to gain information that could help design strategies for future breeding program and conservation of this crop in the two countries. Morphological and molecular markers as well as oil content and quality analyses were employed to evaluate sesame accessions from different sources. High genetic variation was found among populations of sesame collected in Vietnam and Cambodia. The two type of markers, morphological and molecular, were both useful in analyzing the extent of genetic diversity in sesame and the result of these analyses will help to better understand the genetic diversity and relationship within and among populations. Overall, the sesame accessions included in the study showed a correlation with their geographical origins such that accessions from the same region tended to have higher genetic similarity as compared to those from different regions. However, when cluster analysis was applied to evaluate the genetic relationship, some sesame accessions were found not to be grouped based on geographical origins. This contrasting result could perhaps be a result from the exchange over time, of sesame germplasm, between farmers across the regions. The results from morphological and oil content analyses showed that several sesame accessions in Southern Vietnam and Cambodia displayed a good potential for high seed yield and oil content. Overall, the studies in this thesis provide important insights into the populations of sesame in Vietnam and Cambodia and constitute a set of useful background information that can be used as a basis for future breeding strategy and improvement of sesame in this region.
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| 29. |
- Prade, Thomas
(författare)
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Industrial hemp (Cannabis sativa L.) – a high-yielding energy crop
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Bioenergy is currently the fastest growing source of renewable energy. Tighter sustainability criteria for the production of vehicle biofuels and an increasing interest in combined heat and power (CHP) production from biomass have led to a demand for high-yielding energy crops with good conversion efficiencies. Industrial hemp was studied as an energy crop for production of biogas and solid biofuel. Based on field trials, the development of biomass and energy yield, the specific methane yield and elemental composition of the biomass were studied over the growing and senescence period of the crop, i.e. from autumn to the following spring. The energy yield of hemp for both solid biofuel and biogas production proved similar or superior to that of most energy crops common in northern Europe. The high energy yield of biogas from hemp is based on a high biomass yield per hectare and good specific methane yield with large potential for increases by pretreatment of the biomass. The methane energy yield per hectare is highest in autumn when hemp biomass yield is highest. The energy yield per hectare of hemp for use as a solid biofuel is highest in autumn when the biomass yield is highest. However, important combustion-related fuel properties, such as moisture, alkali, chlorine and ash content and ash melting temperature, are significantly improved when industrial hemp is harvested in spring instead of in autumn. Major fuel properties of hemp are not significantly influenced by annual cultivation conditions, latitude or choice of cultivar. Net energy yields per hectare and energy output-to-input ratios of hemp are above-average in most applications, and are highest for use of hemp as solid biofuel. Use of hemp as a biogas substrate suffers from higher energy inputs and lower conversion efficiencies, but produces a high-quality vehicle fuel. Advantages over other energy crops are also found outside the energy balance, e.g. low pesticide requirements, good weed competition and suitability as break crop in cereal-oriented crop rotations. Improvements in hemp biomass and energy yields may strengthen its competitive position against maize and sugar beet for biogas production and against perennial energy crops for solid biofuel production.
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| 30. |
- Riddle, Matthew
(författare)
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Phosphorus leaching from Swedish arable organic soils : quantification and mitigation using biochar
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Organic soils account for 9% or ~225,000 ha of Sweden’s 2.5 million ha of agricultural land, with around half being intensively cultivated. This thesis examines the role of chemical and physical properties of arable organic soils in leaching of phosphorus (P) and whether these losses can be reduced by employing a metal-oxide coated biochar mitigation strategy. These issues were investigated by analysing two organic soils (organic 1 and organic 2) and two P-rich mineral soils (sand and loam) using laboratory and field-based methods. In a rainfall simulation study using short soil columns from four 20-cm soil layers to 80-cm depth, the main location of P release and the concentrations of P leached from the selected organic and mineral soils were identified. The highest concentrations of P were found to be released from the 0- to 20-cm layer in both organic and mineral soils, with 70-90% in phosphate-P form. The highest losses occurred from organic 2, followed by the sand. Soil test total-P correlated well with total-P and phosphate-P in leachate from the rainfall simulation study. A 17-month follow-up study using 90-cm long lysimeters with intact soil revealed that losses were highest from the organic soils, while the sand, known for its high P leaching, had relatively low leaching losses. The amount of total-P leached during the 17-month period decreased in the order: organic 2 (1.2 kg ha-1) > organic 1 (1.0 kg ha-1) > sand (0.3 kg ha-1) > loam (0.2 kg ha-1). Higher P losses from the organic soils were attributed to fewer sorption sites, humic matter competition with phosphate for those same sites and presence of preferential flow pathways (organic 1). Evaluation of ‘Skogens kol’, a wood biochar coated with iron (Fe3O4; magnetite) and ‘Ecoera’, an agricultural residue biochar coated with magnesium (MgO/Mg(OH)2; periclase/brucite) under laboratory conditions revealed a maximum sorption capacity of 3.38 and 65.4 mg P g-1, respectively. Results from the 90-cm lysimeter study also showed greater reductions in P leaching using Mg-coated biochar, with phosphate concentration in leachate being reduced by up to 74% in one organic soil. Magnesium-coated biochar performance was worse in the mineral soils, probably due to greater numbers of sorption sites already being present in those soils. Efficiency of P removal in relation to Fe applied on the biochar was shown to be good in laboratory studies, but poor at field scale. The two organic soils studied leached sufficiently high P concentrations and potential loads to contribute to eutrophication of surface waters. However, due to complex chemical and redox interactions with P, larger field-scale monitoring is required to identify whether the P losses measured in lysimeters are representative of those reaching surface drains.
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| 31. |
- Roos, Jonas
(författare)
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Verticillium longisporum and plant immunity responses in Arabidopsis
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Verticillium spp. are soil-borne ascomycete fungi belonging to a subgroup of Sordariomycetes, and the three major plant pathogens Verticillium longisporum, V. dahliae and V. albo-atrum cause disease on numerous plant species worldwide. In Sweden, V. longisporum poses a threat to Brassica oilseed crops, and is thus emphasized in this thesis. Here the early immune responses to V. longisporum in the model plant Arabidopsis and recent data on the V. longisporum genome are presented. Three genes of importance in the Arabidopsis–V. longisporum interaction were studied. The genes were identified via transcriptome and single nucleotide polymorphism (SNP) analysis. RabGAP22, a RabGTPase-regulating protein, was found to contribute to V. longisporum resistance. Pull-down assays revealed SERINE:GLYOXYLATE AMINOTRANSFERASE (AGT1) as an interacting partner during V. longisporum infection and the two proteins were shown to co-localize in the peroxisomes. Unexpectedly, a role for RabGAP22 was also found in stomatal immunity. The monoterpene synthase TPS23/27 was on the other hand found to contribute to fungal invasion, by triggering germination of V. longisporum conidia. The third gene codes for a nitrate/peptide transporter, NPF5.12. Pull-down experiments and fluorescent imaging revealed interaction between NPF5.12 and a major latex protein family member, NPFBP1. Implications in plant immunity processes of these three genes are further discussed. The genomes of two Swedish V. longisporum isolates were sequenced and found to have a size of approximately 70 Mb and harbor ~21,000 protein-coding genes. Initial analyses revealed that 86% of the V. longisporum genomes are shared with V. dahliae and V. albo-atrum, with a high extent of gene duplications. Large numbers of proteins were predicted to contain secretion motifs, and this group of proteins is presumed to play major roles in the interactions with V. longisporum host plants. In conclusion, this thesis work has revealed new fungal and plant host genes and thereby laid the basis for new plant breeding and disease protection strategies.
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| 32. |
- Svanbäck, Annika
(författare)
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Mitigation of phosphorus leaching from agricultural soils : improved fertilization and soil structure
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Phosphorus (P) is an essential element in crop production, but P losses from agricultural soils are a major contributor to surface water eutrophication. This thesis examined the effects of chemical soil properties and soil structure, as governed by agricultural management practices, on P leaching from agricultural soils and how this leaching can be reduced. An initial investigation on the effect of plant-available P concentration in the soil (P-AL) on topsoil P leaching from five soils clearly showed that topsoil P leaching depends not only on P status, but also on other soil characteristics. In three of these soils, increased P leaching after manure application was further amplified by high P-AL, while manure application did not affect topsoil P leaching in the other two soils. In a study assessing different management practices on a clay soil and the possible effect on P losses via tile drains, great spatial variation in P leaching was observed in the field, even though P-AL and discharge volume were relatively uniform across the field. Incorporation of quicklime (CaO) significantly reduced P leaching losses, primarily of particulate P, which was the dominant P form in drainage water. The other management options evaluated (conventional ploughing/shallow tillage; no P application/balanced P application; broadcasting/band spreading of fertilizer P) had no significant effects on P leaching. However, some effects of these management strategies could have been overshadowed by the large spatial variation in the data. Stopping P application and removing soil P with harvested crops (phytomining) showed potential to reduce excessive P levels in soils. After 7-9 years of no P application to the four soils studied, topsoil P-AL was lowered but most soils still had excessive levels. Only one soil, a clay soil with the lowest P-AL value in the study, showed a significant downward trend in leaching of dissolved reactive P. New knowledge outcomes were that: (i) the relationship between P-AL and topsoil P leaching clearly differs between soils, especially after manure application; (ii) incorporation of quicklime is a promising option for reducing P leaching from clay soils; and (iii) high P-AL values and P leaching may be reduced after phytomining, but this mitigation strategy takes a very long time.
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| 33. |
- Vagiri, Michael
(författare)
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Phenolic compounds and ascorbic acid in black currant (Ribes nigrum L.) : variation due to genotype, ontogenetic stage, harvest date and location
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Black currant is an edible soft fruit crop that is now attracting increased scientific attention due to its high content of potentially beneficial phenolic compounds and ascorbic acid. Using HPLC and spectrophotometry, this thesis examined the content of phenolic compounds in buds, leaves and fruits of black currant plants grown in southern and northern Sweden. In addition, the content of ascorbic acid, soluble solids, titratable acidity and total anthocyanins were studied in the fruits. Differences due to genotype, ontogenetic stage, harvest date and location were determined. The genotypes 'Ben Finlay', 'Poesia' and 'JHI 8944-13' had the highest content of several compounds in both buds and fruits. Among the different bud ontogenetic stages, dormant buds had the highest content of total phenols. In the leaves, the content of phenolic compounds generally varied depending on the position of the leaf on the shoot and on harvest date. A higher content of total phenols was recorded late in the season, except in the basal leaves. Black currant fruits grown in the south had higher contents of most phenolic compounds, ascorbic acid and soluble solids than those grown in northern Sweden. Buds picked from plants grown in the north had higher content of flavan-3-ols, phenolic acids and several flavonols than buds from the south. In conclusion, proper selection of genotype and location for cultivation is essential for promoting the food and health attributes of black currant. Moreover, knowledge related to influence of ontogenetic stage and harvest time on content of specific bioactive compounds in black currant could help tailor functional foods or pharmaceutical products. Black currant production could thereby be carefully planned to enhance the content of specific compounds for product optimisation.
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| 34. |
- Zhu, Tianqing
(författare)
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Regulation of embryo development in Norway spruce by WOX transcription factors
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In seed plants, the apical-basal axis of the plant body is established during early embryogenesis. Major regulatory genes of the apical-basal axis formation belong to the WUSCHEL-RELATED HOMEOBOX (WOX) gene family of transcription factors. The spatiotemporal expression pattern and the molecular role of the WOX genes has mainly been studied in the angiosperm model plant Arabidopsis (Arabidopsis thaliana). Similar information in conifers is limited. The aim of my thesis has been to characterize WOX genes in Norway spruce (Picea abies) and to elucidate the function of WOX genes expressed during embryo development. We cloned 11 WOX homologs from Norway spruce and examined their phylogenetic relationship to WOX genes from other species. The phylogenetic analyses showed that the major diversification within the WOX gene family took place before the gymnosperm-angiosperm split. PaWOX8/9, PaWOX2 and PaWOX3, which are expressed in embryos, were selected for further studies. PaWOX8/9 and PaWOX2 are highly expressed in early and late embryos, and PaWOX3 is highly expressed in mature embryos. Functional studies were performed in RNAi lines where the genes were down-regulated. Embryos in PaWOX8/9 RNAi lines showed a disturbed apical-basal patterning caused by abnormal orientation of the cell division plane at the basal part of the embryonal mass. In PaWOX2 RNAi lines, vacuolated cells differentiated on the surface of the embryonal mass and the embryos failed to form a proper protoderm. Down-regulation of PaWOX3 disturbed lateral margin outgrowth in cotyledons and needles. Taken together, our results indicate that WOX8/9, WOX2 and WOX3 exert evolutionarily conserved functions during embryo development. We can therefore conclude that the regulatory networks of embryo development are at least partly conserved between angiosperms and gymnosperms.
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| 35. |
- Öhman, David
(författare)
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Function of MAP20 and MYB103 in cellulose and lignin formation of xylem secondary cell walls
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Lignocellulose from trees and other crops will have tremendous impact on the next generation of sustainable biofuels and biomaterials. To take advantage of modern breeding tools, it is therefore important to understand the genetic and molecular regulation underlying secondary cell wall formation. Here, functional analysis was performed on two genes specifically involved in secondary cell wall formation, using Arabidopsis and Populus as model species. PttMAP20 was earlier identified as a wood-specific microtubule-associated protein in hybrid aspen, but not functionally assessed [Rajangam et al. (2008). Plant Physiology, pp. 1283–1294]. In this thesis, AtMAP20 was found to be generally expressed in secondary wall forming cell types in Arabidopsis, including xylem cells, and its binding to microtubules was confirmed. A domain-mapping study showed that its central TPX2 domain, together with the N- and/or C-terminal domain, is required for complete microtubule binding. Overexpression of AtMAP20 induced shorter roots and right-handed twisting, mimicking treatment with the microtubule-stabilizing drug taxol. Loss-of-function map20 mutants had longer etiolated hypocotyls and altered cell wall chemistry. This phenotype was interpreted as resulting from mechanical weakening in the secondary walls of their spiral protoxylem vessels. In line with this, overexpression of PttMAP20 in hybrid aspen affected cellulose microfibril angle. Taken together, MAP20 is a novel microtubule-stabilizing protein, specifically active during secondary cell wall formation and important for the patterning of cellulose microfibrils. MYB103 is a xylem-specific transcription factor, previously demonstrated to be directly activated by the secondary wall NAC master switches SND1/NST1 and VND6/VND7 [Zhong et al. (2008). Plant Cell, pp. 2763–2782]. This thesis demonstrates that loss-of-function Arabidopsis myb103 mutants have reduced levels of syringyl lignin in their basal stems. This was compensated for by an increase in guaiacyl lignin, resulting in a modified syringyl to guaiacyl ratio. The altered lignin composition, characterized by Py/GC-MS, FT-IR microspectroscopy and 2D NMR, was caused by a suppression of F5H, a key gene in syringyl lignin biosynthesis. Thus, it is concluded that MYB103 is required for F5H expression. Taken together, this thesis presents novel knowledge on function of genes important for secondary cell wall formation and, hence, wood formation. These findings have the potential to improve wood characteristics to benefit forest growers and industries.
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| 36. |
- Önneby, Karin
(författare)
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Bioaugmentation for reduction of diffuse pesticide contamination : a bioprophylactic concept
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Pesticides and their residues frequently contaminate surface waters and groundwater so consequently there is a great need to identify methods and practices that reduce such contamination. This thesis examined the potential of a 'bioprophylactic' concept based on the hypothesis that diffuse contamination after application in the field can be significantly reduced if pesticides are degraded as rapidly as possible after the intended effect has been achieved. This involves adding pesticide degraders together with the pesticide at the time of application. Such enhanced degradation is particularly important for pesticides used on non-agricultural soils with low degradation and high leaching potential (e.g. roadsides, railway embankments, paths, farmyards, urban land). The herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA) was used as a model herbicide in this thesis, together with its degrader Sphingobium sp. T51. Soil inoculation with Sphingobium sp. T51 in microcosms significantly enhanced the degradation of MCPA compared with an uninoculated soil, without losing the herbicidal effect. In sand, 105 cells g-1 dry weight of soil reduced the MCPA concentration by 79-86% within one day, while only 0-31% reduction was observed in the uninoculated control after three days. However, Sphingobium sp. T51 needs to be formulated to retain its viability and degradation activity during prolonged storage and also for protection from the harsh environmental stresses associated with its application and functioning in the field. Both freeze drying and fluidised bed drying of Sphingobium sp. T51 resulted in high initial cell survival rates, of 67-85%. The storage stability of formulated Sphingobium sp. T51 was dependent on the formulation excipient/carrier used, storage temperature and atmospheric conditions. Sphingobium sp. T51 demonstrated approximately 50% survival in a freeze-dried sucrose formulation after six months of storage under partial vacuum at 25 °C. A fluidised bed-dried formulation with cottonseed flour as carrier resulted in the highest MCPA degradation in microcosms, but the storage stability was insufficient. Formulated and long-term stored Sphingobium sp. T51 reduced pesticide leaching by 85-94% of the total amount added in sand columns. Future research needs regarding practical implementation of the concept are discussed.
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| 37. |
- Stengärde, Lena
(författare)
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Displaced abomasum and ketosis in dairy cows : blood profiles and risk factors
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- High producing dairy cows struggle to meet energy demands and handle various transitional changes in late gestation and early lactation. Negative energy balance in early lactation is inevitable and metabolic disorders may follow as a consequence of a deep negative energy balance. This thesis studies associations between blood profiles and body condition score (BCS) in dairy cows, and displaced abomasum (DA) or clinical ketosis, and investigates risk factors for the two diseases at the herd level. In study I, blood profiles of cows with and without DA were compared. In studies II and III, blood of cows was sampled to investigate how blood profiles differed among herds with a high incidence of DA or clinical ketosis, and between cows in high-incidence and low-incidence herds, respectively. In study IV, associations between high or low incidence and factors related to housing, feeding, management and milk yield were studied to identify herd-level risk factors for DA and ketosis. The blood profiles included parameters with which to assess energy metabolism, hepatic cell damage, inflammation, and a metabolic index (RQUICKI)used in humans to assess insulin sensitivity. The cows with DA displayed blood profiles indicating a severely altered energy metabolism (NEFA, BHB, insulin, cholesterol, RQUICKI), liver cell damage (AST, GD) and inflammatory responses (haptoglobin). At the herd level, energy markers (NEFA, insulin, glucose, cholesterol, RQUICKI) indicated altered metabolism in cows in high-incidence herds compared with cows in low-incidence herds. The markers of liver cell damage and inflammation were not different between highand low-incidence herds. Among high-incidence herds, BCS and change in BCS, and one metabolic marker (NEFA) were found most useful to pinpoint herd problems. Large herd size, high individual milk production level, keeping all dry cows in one group, and not cleaning the feeding platform daily, were found to be risk factors for a high incidence of DA or ketosis at the herd level. In conclusion, the studies confirm a difference in blood profiles between cows with DA and healthy herd mates as well as a difference at the herd level between cows in herds with high versus low incidence of DA and clinical ketosis.
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| 38. |
- Paulraj, Thomas
(författare)
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Plant cell-inspiredmicrocontainers: Fabrication, Characterization and Applications
- 2019
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Konstnärligt arbete (övrigt vetenskapligt/konstnärligt)abstract
- Biomimetic materials have been inspiring mankind since a longtime for applications in a variety of fields. In particular, the production of lipidbasedvesicles have aided in our understanding of a variety of functions in animalcells, and also served as e.g. drug delivery systems and bioreactors. On thecontrary, the preparation of synthetic plant cells is limited, which is mainly due tothe challenges of building the complex plant primary cell wall fencing the lipidplasma membrane in real plant cells.The present thesis focuses on the bottom-up fabrication ofbiomimetic microcontainers that can serve as simple model systems for plant cells.In the first part, the interactions of plant cell wall polysaccharides, cellulosenanofibers (CNFs), pectin and xyloglucan, are examined. The knowledge is used inthe fabrication of microcapsules and the permeability properties were assessed.The results show that the polysaccharides must be assembled in a specific order inthe capsule wall to incorporate all the three polysaccharides. Additionally, thestructural stability and permeability highly depend on the capsule wallcomposition. The permeability also depends on the composition of thesurrounding media.The second part deals with the fabrication of more advancedbiomimetic microcapsules, with a lipid layer beneath the polysaccharide capsulewall. These capsules are semi-permeable and the phase behavior of the lipids isexploited to grow tubular structures (long filamentous structures) through thecapsule wall, as well as create a vesicle-crowded interior. Real plant cells usetubular structure (Plasmodesmata) for intercellular communications.In the third part, application-oriented aspects of the fabricatedmicrocapsules are discussed. The LbL-derived microcapsules (from the first part)were loaded with active glucose oxidase enzyme, thereby allowing their use as aglucose sensor. The capsule wall acts like a sieve, only allowing small molecules toeffectively pass through. Finally, cell culture experiments demonstrate theirbiocompatibility, paving way for tissue culture applications.
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| 39. |
- Lindström, Sandra
(författare)
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Insect pollination of oilseed rape
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Ecological intensification of agriculture is suggested as a way to reach higher crop yields without increasing inputs that may degrade the environment. Increased insect pollination in crops, such as oilseed rape, Brassica napus, has been suggested to increase yields, but is rarely integrated in crop management. To determine the value of enhanced crop pollination as a means of ecological intensification, reliable estimates of how yield is affected by insect pollination are needed. Further, little is known about interactions between insect pollination and other crop management factors such as cultivar, nitrogen fertilization, pest control, and irrigation. Finally, it needs to be assessed how increasing crop pollination by adding honey bees to crops impact the wild fauna of flower-visiting insects. I addressed these issues in two sets of experiments. First, I performed a landscape-scale experiment with replicated whole fields of winter oilseed rape. I manipulated the pollinator community by adding honey bee hives or controlled the surroundings for absence of honey bees. I chose fields such that they were embedded in either intensive-ly cropped landscapes or heterogeneous landscapes with more semi-natural pastures, expecting greater diversity of wild pollinators in the latter. In two cultivar types, I examined how honey bee addition affected crop yield and the wild pollinator community. Second, I performed two field plot experiments, in winter and in spring oilseed rape, to assess how insect pollination and the crop management factors cultivar, nitrogen fertili-sation, pest control, and irrigation interactively shaped crop yield. Insect pollination increased winter oilseed rape yield, but only in open-pollinated cultivars. Cultivars of open-pollinated type gave higher yields than cultivars of hybrid type. Thus, phasing out open-pollinated cultivars from the market emerges a missed opportunity for increased yields. I show that the crop’s access to water, nitrogen, and herbivory affect pollinator behaviour and potentially crop pollination. Interestingly, insect pollination tended to increase yields when no nitrogen was applied, indicating higher nutrient use efficiency in plants with access to insect pollination. Adding managed honey bee hives had nega-tive effects on the densities of wild flying- and flower-visiting insects, with potential negative effects on crop pollination and biodiversity conservation. Overall, my thesis demonstrates the importance of including both agronomic and environmental perspectives when developing crop production systems that are productive and sustainable.
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| 40. |
- Nickel, David, 1990
(författare)
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Process development for platform chemical production from agricultural and forestry residues
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- As part of a bio-based economy, biorefineries are envisaged to sustainably produce platform chemicals via biochemical conversion of agricultural and forestry residues. However, supply risks, the recalcitrance of lignocellulosic biomass, and inhibitor formation during pretreatment impair the economic feasibility of such biorefineries. In this thesis, process design and assessment were developed with the aim of addressing these hurdles and improving the cost-effectiveness of lignocellulose-derived platform chemicals. To expand the feedstock base and reduce operational costs, logging residues served as underutilised and inexpensive raw material. The major impediment in converting logging residues was their high recalcitrance and low cellulose content, which resulted in low attainable ethanol titres during simultaneous saccharification and co-fermentation (SSCF). Pretreatment optimisation reduced inhibitor formation and recalcitrance, and led to enzymatic hydrolysis yields at par with those obtained for stem wood, despite the less favourable chemical composition. Upgrading logging residues with carbohydrate-rich oat hulls increased ethanol titres to >50 g/L using batch SSCF at 20% WIS loadings, demonstrating the potential to further decrease downstream processing costs. To alleviate the toxicity of inhibitors generated during pretreatment, preadaptation was applied to Saccharomyces cerevisiae . Exposure to the inhibitors in the pretreated liquid fraction improved ethanol production during subsequent fermentation. Transferring the concept of preadaptation to lactic acid production by Bacillus coagulans cut the process times by half and more than doubled the average specific lactic acid productivity, showcasing how preadaptation could decrease operational costs. To assess the performance and robustness of process designs against process input variations, a multi-scale variability analysis framework was developed. The framework included models for bioprocess, flowsheet, techno-economic, and life cycle assessment. In a case study, multi-feed processes, in which solids and cells are fed to the process using model-based predictions, were more robust against variable cellulolytic activities than batch SSCFs in a wheat straw-based ethanol biorefinery. The developed framework can be used to identify robust biorefinery process designs, which simultaneously meet technological, economic, and environmental goals.
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| 41. |
- Englund, Oskar, 1982
(författare)
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On Sustainability of Biomass for Energy and the Governance Thereof
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Due to concerns about climate change, energy security, and resource scarcity, non- renewable resources are increasingly being displaced by biomass. As with most human activities, the production of biobased products can be associated with negative impacts. Primarily, this relates to the biomass supply systems, i.e., agriculture and forestry, which currently are major causes of biodiversity loss and degradation of ecosystem services. Developing sustainable production systems when transitioning from non-renewable resources to biomass is imperative. This thesis aims to clarify the meaning of sustainability in the context of biomass for bioenergy, and contribute to our understanding of how different forms of governance can promote sustainably sourced biomass for bioenergy. The thesis is based on five appended papers: Paper I analyses to what extent, where, and under what conditions oil palm for biodiesel in Brazil can be produced profitably, and what risks and opportunities that can be associated with introducing large-scale oil palm production in Brazil. Paper II lays the foundation for understanding how new biomass production can be introduced into landscapes while supporting rather than compromising the ability of the landscape to supply other ecosystem services. Paper III describes different forms of governance and shows how these can play different roles in promoting sustainable bioenergy in different countries. Paper IV focuses on how short rotation coppice production systems are affected by EU policy and how different governance forms can assist in adapting production systems to conform to the corresponding sustainability requirements. Finally, Paper V assesses how sustainability certification (private governance) addresses biodiversity conservation and contributes to our understanding of possible improvements.
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| 42. |
- Åstrand, Björn, 1969-
(författare)
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Vision Based Perception for Mechatronic Weed Control
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The use of computer-based signal processing and sensor technology to guide and control different types of agricultural field implements increases the performance of traditional implements and even makes it possible to create new ones. This thesis increases the knowledge on vision-based perception for mechatronic weed control. The contributions are of four different kinds:First, a vision-based system for row guidance of agricultural field machinery has been proposed. The system uses a novel method, based on the Hough transform, for row recognition of crop rows.Second is a proposal for a vision-based perception system to discriminate between crops and weeds, using images from real situations in the field. Most crops are cultivated in rows and sown in a defined pattern, i.e. with a constant inter-plant distance. The proposed method introduces the concept of using these geometrical properties of the scene (context) for single plant recognition and localization. A mathematical model of a crop row has been derived that models the probability for the positions of consecutive crops in a row. Based on this mathematical model two novel methods for context-based classification between crops and weeds have been developed. Furthermore, a novel method that combines geometrical features of the scene (context) and individual plant features has been proposed. The method has been evaluated in two datasets of images of sugar beet rows. The classification rate was 92 % and 98 %, respectively.The third contribution is the design of a mobile agricultural robot equipped with these perception systems and a mechanical weeding tool intended for intra-row weed control in ecologically cultivated crops.The fourth contribution is a demonstration of the feasibility of the perception systems in real field environments, especially with respect to robustness and real-time performance. The row guidance system has been implemented in three different row cultivators and performed inter-row weed control at two commercial farms. The robot has proven to be able to follow a row structure by itself, while performing weed control within the seed line of a crop row, i.e. intra-row cultivation.
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| 43. |
- Aboshady, Hadeer Moursy
(författare)
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Genomic variation and molecular mechanisms of the host response to gastrointestinal nematodes in small ruminants
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Gastrointestinal nematode (GIN) infections are one of the major constrains for sheep and goat production worldwide. One of the promising control strategies is the genetic selection for resistant animals as there are no issues due to anthelmintic resistance and it aligns to demands for chemical-free food. Exploring possible phenotypic and genomic markers that could be used in breeding scheme besides understanding the mechanisms responsible for resistance were the main goals of this thesis. Thesis consists of General introduction, a brief description of GIN biology and methods to control GIN with focus on phenotypic and genomic markers, four papers and General discussion. In paper Ⅰ, a systematic review and meta-analysis were conducted to re-analyse and summarize the findings on immunoglobulins response to GIN in the literature and discuss the potential to use immunoglobulins as biomarkers of the host resistance. A conceptual model summarizing the role of immunoglobulins in resistance to GIN is proposed. In paper Ⅱ, transcriptome profiling of the abomasal mucosa and lymph node tissues were compared between non-infected, resistant and susceptible Creole goats experimentally infected with Haemonchus contortus. Results indicated that the maintenance of the integrity of the mucosa has probably the priority for the host at late infection stage. In paper Ⅲ, the dynamics of the response of the abomasal mucosa of resistant and susceptible Creole goats experimentally infected with H. contortus were compared. The immune response was activated through many relevant pathways including the Th1 immune response at different time post-infection. Interestingly, the results showed a simultaneous time series activation of Th2 related genes in resistant compared to susceptible kids. In paper Ⅳ, the genomic variants of Creole goats resistant and susceptible to H. contortus were discovered from RNAsequencing data at four different times post-infection. Single nucleotide polymorphisms, insertions and deletions that distinguish the resistant and the susceptible groups were identified and characterized through functional analysis. The T cell receptor signalling pathway was one of the top significant pathways that distinguish the resistant from the susceptible group with genomic variants in 78% of genes in this pathway.
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| 44. |
- Al-Azzawi, Zaenab
(författare)
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The role of biological processes in base cation supply in boreal forest podzols
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis describes experiments designed to improve understanding of biological processes contributing to supply of base cations and other nutrients in boreal forest podzols. We used microcosms containing tree seedlings growing in natural substrates, a combination of direct measurements, modelling, stable Mg isotope analysis, and 13CO2 pulse-labelling. Addition of 13C-labelled fungal necromass to soil resulted in rapid decomposition and active incorporation of 13C into RNA of Burkholderia, Streptacidophilus, Dyella, Herminiimonas, Granulicella and fungal species belonging mainly to the genera Mortierella and Umbelopsis. There was no evidence of 13C incorporation into RNA of ectomycorrhizal fungi supporting the idea that ectomycorrhizal fungi primarily play an active role in organic matter decomposition by releasing N from recalcitrant substrates, but do not use organic matter as a source of metabolic C. Selected ectomycorrhizal and nonmycorrhizal fungi were examined for their capacity to fractionate and assimilate stable Mg isotopes in vitro. Ectomycorrhizal fungi mobilised and accumulated significantly higher concentrations of Mg, K and P than nonmycorrhizal fungi, when grown on granite particles. Mycorrhizal fungi were significantly depleted in heavy isotopes compared with nonmycorrhizal fungi and there was a highly significant statistical relationship between δ26Mg tissue signature and mycelial concentration of Mg. Pinus sylvestris seedlings were grown in compartmentalised microcosms allowing their mycorrhizal mycelium, but not roots, to access different substrates, including granite particles. Root biomass and contents of Ca, K, Mg, and P in plants in granite treatments were significantly higher than in control roots. Carbon allocation by the ectomycorrhizal mycelium to soil solution was significantly and positively correlated with base cation and P content of the plants. A final experiment (using reconstructed boreal forest podzol layers) was conducted in which the relative amounts of organic and mineral substrates were manipulated to simulate different levels of intensification of the removal of organic matter. All plants were deficient in K and P but had above optimal levels of Ca and Mg. Total plant and fungal mycelial biomass was positively related to the amount of organic soil in each treatment. The δ26Mg values of soil solution samples in B horizon soil increased successively with increasing plant and fungal mycelial biomass, suggesting increased uptake of Mg from the B horizon, with discrimination against the heavier isotope resulting in higher enrichment of 26Mg.
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| 45. |
- Amera sahilu, Tadesse
(författare)
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Stewardship towards responsible management of pesticides : the case of Ethiopian agriculture
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis examines pesticide use, practice and associated human health and environmental impacts in the Ethiopian Rift Valley. It uses participatory action research as a philosophy and methodology in order to understand the Ethiopian pesticide delivery system so as to bridge the gap amongst the main actors and create a space for dialogue. The pesticide delivery system in Ethiopia comprises policy makers, researchers, pesticide manufacturers, wholesalers, vendors, civil societies and farmers. These actors with divergent interests had been working in a dispersed manner with no concerted effort to mitigate the problem. Stewardship as a moral obligation to mitigate the problem was, therefore, introduced to the actors. The aim was to bring these actors together so as to initiate a system-wide pesticide users’ stewardship network that shared a sense of responsibility at all levels to bring about an ethic of reduced and responsible use of pesticides. This was first initiated by establishing a national (meta) level multiactor pesticide stewardship association which later triggered a regional (meso) level pesticide risk communication and local (micro) level action-oriented alternative pest management experimentation through farmer field schools. Combined methods of qualitative and quantitative data collection were used to explore the processes at all levels. The process revealed that the meta level network was viewed by all actors as a platform for collaborative learning and collective action driving institutional change at many levels. The meso level showed that even if the pesticide hazards were evident and different types of safe use training was provided, farmers’ risk perception continued to be low while associated hazards remained high. This was, therefore, attributed to lack of proper risk communication, which requires reframing of the approach that promotes pesticides only as a means for agriculture productivity but gives less attention to their negative impacts. The micro level showed the field-based action as a means of participatory knowledge co-production, which has been contributing to transformation towards the overarching goal of pesticide users’ stewardship. This process faced multilevel communicative, systemic, organizational and societal barriers that challenged the federal level initiative but has been well managed by the local level action, which has been a lesson for federal level actors
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| 46. |
- Anderson, Jenna
(författare)
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Development and evaluation of a subunit DIVA vaccine against bluetongue virus serotype 8 in cattle
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Bluetongue virus (BTV) causes the primarily vector-borne bluetongue disease of ruminants, which poses a permanent threat to Europe since new serotypes and strains are frequently introduced. Vaccination of cattle is essential to control BTV outbreaks. Commercial attenuated and inactivated vaccines are efficacious in reducing BTV spread and disease, but do not fulfil all safety, adaptability, or production requirements. Additionally, no current vaccines allow the differentiation of infected from vaccinated animals (DIVA). DIVA vaccines enable surveillance of BTV epidemiology and vaccine efficacy, and facilitate a quick return for countries to a BTV-free status. This thesis presents the development and evaluation of a novel subunit DIVA vaccine against BTV serotype 8 (BTV-8) in cattle. Five His-tagged recombinant BTV proteins (VP2, VP5 of BTV-8; NS1, NS2, NS3 of BTV-2) were produced in baculovirus or E. coli expression systems. Purification protocols were optimized for all but VP5. Based on the feasibility of protein production and the capability of the remaining four proteins to induce humoral or cellular immune responses in mice, VP2, NS1, and NS2 were selected to formulate an experimental vaccine combined to an ISCOM-matrix adjuvant (SubV). Next, cattle were immunized twice at a three-week interval with SubV, a commercial inactivated vaccine, or a placebo. SubV induced humoral immune responses, including virus-neutralizing antibodies, against all three proteins, as well as a cellular immune response directed against NS1. These responses were of similar type and comparable magnitude between both vaccines, suggesting that SubV might provide protection that is at least as effective as the commercial vaccine. Finally, the protective efficacy of SubV was evaluated and complete virological and clinical protection against virulent BTV-8 challenge was observed following vaccination in calves. This was likely due to the induction of virus-neutralizing antibodies directed against VP2 of BTV-8 and cross-serotype T cell responses directed against NS1 and NS2 of BTV-2. Furthermore, SubV was shown to be DIVA-compliant based on the detection of antibodies directed against VP7, by using commercially-available diagnostic assays. This novel BTV subunit vaccine is a promising candidate and should be further developed.
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| 47. |
- Anglart, Dorota
(författare)
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Indicators of mastitis and milk quality in dairy cows : data, modeling, and prediction in automatic milking systems
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Methods for generating predictions of important and generally accepted indicators of udder inflammation and poor milk quality, such as somatic cell count (SCC) or changes in milk homogeneity, are few. The aim of this thesis was to investigate methods to identify indicators of mastitis and poor milk quality in dairy cows using data generated by automatic milking systems (AMS).The first part of the project investigated the relationship between SCC and data regularly recorded by the AMS using models that could capture nonlinear associations between the explanatory variables and the outcome. This information could be used in modeling the SCC. Furthermore, three statistical methods, generalized additive model, random forest and multilayer perceptron, were compared for their ability to predict SCC using data generated by the AMS. The results showed that equally low prediction error was obtained using generalized additive model or multilayer perceptron for prediction of SCC based on AMS data.The second part explored the dynamics of changes in milk homogeneity in cows milked in AMS using descriptive statistics for clots collected by inline filters, scored for density. Clots were found among certain cows and cow periods and appeared in new quarters over time. Models were fitted for detecting and predicting clots in single cow milkings as well as for detecting clots in milkings over a longer period. The models successfully distinguished periods of milking free of changes in milk homogeneity, although the detection and prediction performance was poor. The prediction target and severity grade of each density category is discussed.
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| 48. |
- Arif, Usman
(författare)
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Effect of wounding and light exposure on sterol, glycoalkaloid, and calystegine levels in potato plants (Solanum tuberosum L. group Tuberosum)
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Steroidal glycoalkaloids (SGA) are neurotoxic substances that are present in some members of the Solanaceae family, including crop species like potato (Solanum tuberosum L.) and tomato. The SGA level in the potato tuber is a genetic trait, but certain environmental factors such as wounding and light exposure can increase SGA levels several-fold, which may render tubers unsuitable for human consumption. There is little information about SGA biosynthesis. The sterol cholesterol is commonly regarded as a SGA precursor, but there is little evidence for this view. To increase our understanding of the SGA biosynthesis and its molecular regulation, a microarray screen was performed using tubers from two potato cultivars subjected to wound and light treatments. Along with an alteration of sterol and SGA levels, the treatments were associated with an up-regulation of a small set of genes in sterol and SGA metabolism, including a gene encoding for the sterol reductase DWF1. DWF1 genes were found in two differentially regulated subtypes; DWF1 and DWF1-like (DWF1-L). Alteration of DWF1 and DWF1-L expression in transgenic potato showed a role for these genes in sterol and SGA synthesis. Also up-regulated in the microarray study were three transaminase-like genes, and role of StTAM1 in SGA synthesis was investigated by overexpression in transgenic potato. This resulted in elevated SGA levels, indicating the presence of a transamination in SGA synthesis. The genetic variation and stress responsiveness in Swedish potato cultivars regarding SGA and calystegine alkaloids (CA) level was determined by subjecting tubers to wounding, light exposure and elevated temperature. Only light and wounding increased SGA levels, and variation in the response was observed among the cultivars. CA levels were not stress-regulated, indicating that SGA and CA synthesis are not interrelated. These results show that the SGA level in potato tubers are regulated by a concerted action of a small set of key genes acting at different steps in the sterol and SGA pathways. Results also demonstrate a genetic variation in stress responsiveness among Swedish potato cultivars, and have identified the most sensitive ones. Results could in the near future be used to improve post-harvest handling of potato cultivars.
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| 49. |
- Arvidsson Segerkvist, Katarina
(författare)
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Factors affecting fatty acid composition in forage and milk
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aims of the studies underlying this thesis were to evaluate variations in fatty acid (FA) contents of plants used as forage for dairy cows in northern Sweden, and their effects on the FA contents of the milk. Initially, samples of timothy (Phleum pratense L.) were subjected to different pre-treatments prior to analysis. Freezing with liquid N was not necessary to obtain apparently reliable FA profiles of the samples examined. The prevailing method for handling samples before analysis, i.e. freeze-drying and grinding, was satisfactory. However, heat drying samples at 60°C was just as good, or even better in some cases. Neither wilting (to 330-350 g dry matter/kg) nor application of additives (acid additive or bacterial inoculant) to timothy had any substantial effects on the proportions of FAs in silage. In addition, seasonal variations in FA concentrations were evaluated in timothy and meadow fescue (Festuca pratensis Huds.) subjected to three different N fertilization regimes and harvested at different stages of maturity during their spring and summer growth periods. FA concentrations in both grasses declined over time in both growth periods. There were positive linear relationships between FAs and concentrations of crude protein (CP) and crude fat, which might be useful as tools to predict FA concentrations in the forage. Furthermore, the two grass species examined showed differences in FA profiles, notably timothy had higher concentrations of C18:2 n-6 and meadow fescue higher concentrations of C18:3 n-3, but the total fatty acid concentrations were similar in both grasses. In addition, three timothy silages subjected to different N-fertilization regimes and a red clover/timothy silage (60:40 on DM basis) were fed to 24 dairy cows in a change-over design. Higher levels of N-fertilization led to higher concentrations of CP accompanied by higher concentrations of FAs in silage. However, these differences did not affect the concentrations of either protein or 18:3n-3 in the milk of cows fed these grass silages, but including red clover in the cows’ diet led to increased concentrations of C18:3 n-3 and cis-9, trans-11 18:2 in their milk.
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| 50. |
- Asplund, Linnea
(författare)
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Nitrogen use efficiency and related functional traits in wheat : influence of genotype and environment
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Efficient use of nitrogen (N) is essential to decrease negative impacts of agriculture on the environment. This thesis evaluated the nitrogen use efficiency (NUE) of various wheat varieties, identified traits associated with high NUE and investigated the gene NAM-B1 in relation to some of these traits. To achieve this, a NUE concept was first developed. Six varieties each of winter and spring wheat (Triticum aestivum ssp. aestivum) at two levels of N fertilisation were studied in a one-year field experiment. A greenhouse experiment was performed with the same six spring wheat varieties at two levels of N fertilisation and three levels of drought. Forty-two varieties of spring wheat were grown in a climate chamber experiment. Furthermore, 527 wheat accessions were genotyped for their allele type of NAM-B1, a gene known to affect grain N concentration and senescence of wheat. The NUE concept developed here proved relevant in different experimental set-ups, as shown by the varieties ranking similarly in overall NUE and uptake efficiency in the greenhouse and the field. Associations between functional traits and NUE were more evident at low than at high N, suggesting that functional traits might be particularly useful for identifying efficient varieties in limiting N conditions. Grain N content was associated with chlorophyll in the top leaf around anthesis (measured by a SPAD chlorophyll meter) both in the climate chamber and in winter wheat in the field. This suggests that a high SPAD value in a variety can be used as an indicator of high N yield. Genotyping revealed that the functional allele of NAM-B1 has been preserved in many varieties from Denmark, Finland, Norway and Sweden, but not in varieties from other parts of the world. Swedish varieties with this functional allele did not have higher grain N concentrations, but had accelerated senescence and more ears. Effects of the allele in different environments, e.g. varying temperature and fertilisation, should be further investigated to determine when this allele has positive effects on grain N concentration and yield.
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