363 research outputs found
Modelling Transport in an Interregional General Equilibrium Model with Externalities
In this working paper the regional impacts of road pricing on cars are analysed taking into account externality effects from transportation on wages and productivity. In the paper the direct impacts from changes in transport costs on level of wages and productivity (=direct externality effects) have been estimated. The direct and derived impacts of road pricing have been analysed with AKF’s local economic model LINE and include the impacts on regional production, income and employment. LINE is an interregional general equilibrium model, which uses an interregional social accounting matrix (SAM-K) and a regional transport satellite account as the basis for modelling. Additionally, data from a GIS-system (Technical University of Copenhagen) on transport costs have been included to estimate the demand for transport commodities and increase in transport demand and costs due to road pricing. The direct effects on level of wages and productivity have been included into the model together with all the direct effects on commodity prices from road pricing. In the working paper the total impacts of road pricing have been subdivided into 2 components: 1) The wage effects of reducing income net of commuting of increasing transport cost by introduction of road pricing, 2) the labour contraction effect from increasing wages through increase in commuting cost and 3) the negative productivity effects of introducing road pricing. In total the impacts of road pricing are substantial. Regions with high level of average commuting cost (suburban areas in Greater Copenhagen) suffers most, whereas the centre of Copenhagen suffers least because of short commuting distances. In rural areas impacts are on or just below average because low level of road pricing.
Selection for resistance against root pathogens in a pea composite cross
The possibility of improving resistance in pea against the root pathogen Aphanomyces euteiches using composite cross as a breeding and selection method was examined. In order to maintain acceptable agricultural features and high yield 6 out of the 8 parental varieties in the present composite-cross were commercially grown varieties. Populations of the composite cross were grown up to five generations with selection pressure in soil heavily infested with pea root pathogens or without selection pressure on soil free of pea root pathogens. Yield of populations of the F9 and F10 generations of the composite cross grown with selection pressure was on average 35% higher than that of the population obtained without selection pressure as well as the average yield of the 8 parentals of the composite cross, which were of similar magnitude. In healthy soil the yield was overall higher than in the pathogen-infested soil, but yield did not differ between the populations from the composite cross with and without selection pressure, which were also similar to the average yield of the 8 different parentals. Recombinant inbred lines (RILs) randomly selected from the F10 population with selection pressure developed 23% less root rot than the corresponding F10 population without selection pressure, when grown in field soil heavily infested with pea root pathogens. Surprisingly, greenhouse pot experiments with pure cultures of the pea root pathogen A. euteiches resulted in higher root disease, in RILs from populations with selection pressure than from corresponding RILs without selection pressure. Problems related to greenhouse screening for resistance is discussed as well as the possibilities of using composite cross as a method to improve resistance against root diseases in grain legumes
Specificity of soil-borne pathogens on grain legumes
Specificity of soil-borne legume pathogens on pea, lupin and faba bean is currently investigated in fields where grain legumes are intensively cultivated.
The study has so far lead to the following conclusions
-Legume host-pathogen interactions demonstrate specificity of pathogen populations particularly in pea and lupin.
-A. euteiches rot root was specified to pea in Denmark as root rot symptoms and oospores of the pathogen never were observed in roots of faba bean and lupin
-F. oxysporum followed by F. solani were most frequently isolated from plant roots in plots highly infested by lupin pathogens
-F. avenaceum was most frequently isolated from plant roots in plots highly infested by pea pathogens
-Pathogenicity tests showed F. solani followed by F. avenaceum to be the most pathogenic Fusarium species on pea while F. avenaceum was the most destructive pathogen on faba bean. In contrast F. avenaceum was non-pathogenic on lupin
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