Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2019
Authors
Lars T. HavstadAbstract
No abstract has been registered
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No abstract has been registered
Authors
Lars T. HavstadAbstract
No abstract has been registered
Authors
Lars T. HavstadAbstract
No abstract has been registered
Abstract
For plum production to be economically viable, dwarfing rootstocks are essential for establishing high-density orchards, which ensure easier management, lower production costs, and earlier yields. Performance of the semi-dwarfing plum rootstocks ‘Wavit’, ‘Ute’ (both clones of Prunus domestica), and the dwarfing ‘VVA-1’ (Krymsk®1) was compared against the industry standard, ‘St. Julien A’. Onto these rootstocks, scion cultivars ‘Excalibur’, ‘Reeves’, and ‘Valor’ were grafted and assessed in a replicated field trial in western Norway at 60° North. Trees were planted in spring 2006 and the ‘VVA-1’ rootstock in May 2007. Plants were all one-year-old whips, spaced 2.0×4.0 m apart and trained to a central leader as free spindles. Tree vigour, yield, fruit size, fruit quality, and yield efficiency were evaluated for eight subsequent years. Tree size was significantly influenced by the rootstock after eight years of growth. ‘VVA-1’ produced the smallest trees, about half the tree size of ‘St. Julien A’ as measured by trunk cross-sectional area. ‘Wavit’ and ‘Ute’ were similar in size to ‘St. Julien A’. All plum trees came into production slowly. On average the cultivars ‘Excalibur’ and ‘Reeves’ were harvested in mid-September and ‘Valor’ two weeks later. During the period 2011-2014, when trees were fully mature, ‘Reeves’ and ‘Valor’ grafted on the three semi-dwarfing rootstocks resulted in the highest yields tree-1. ‘VVA-1’ resulted in significantly lower yields for ‘Valor’. ‘Excalibur’ was the only cultivar in which ‘VVA-1’ significantly increased yield efficiency. Accumulated yield from 2011-2015 on ‘VVA-1’ was 0.52 kg cm-2 TCSA, 2.3 times more than on ‘St Julien A’. Fruit weight in ‘Excalibur’ and ‘Reeves’ was on average 57 and 62 g, respectively, and not affected by the different rootstocks. ‘Valor’ on ‘VVA-1’ showed a 10 g reduction in fruit weight compared to 59 g fruit weight on the other rootstocks. Fruit soluble solids were on average around 13 °Brix for ‘Excalibur’ and ‘Reeves’ and 16 °Brix for ‘Valor’ and did not differ significantly between trees on the different rootstocks tested. In conclusion, ‘St. Julien A’ was the most reliable semi-vigorous rootstock and resulted in the highest accumulated yields over the first eight years after planting and with favourable effects on fruit quality of all European plum cultivars evaluated. ‘VVA-1’ resulted in trees of low vigour which, especially with ‘Excalibur’, were more precocious and had higher yield efficiencies than all other rootstock scion combinations. If this rootstock is to be used it should be planted at a higher density per area than the semi-dwarfing rootstocks and on fertile soil with fertigation provided.
Authors
Åsmund Asdal Roland von Bothmer Guro Brodal Ulrika Carlson-Nilsson Axel Diederichsen Dag Terje Filip Endresen J. Engels Annette Hägnefelt M El-Khalifeh Helmut Knüpffer Igor Loskutov Udda Lundqvist Eivind Meen Anders Nilsson Anna Palme Jan Svensson Peter Tigerstedt Jens WeibullEditors
Flemming Yndgaard Svein Øivind SolbergAbstract
No abstract has been registered
Authors
Åsmund Asdal Guro Brodal Svein Øivind Solberg Flemming Yndgaard Roland von Bothmer Eivind MeenAbstract
Lenke til utgiver / Link to publisher: https://www.nordgen.org/en/publications/seed-longevity-and-survival-of-seed-borne-diseases-after-30-years-conservation-in-permafrost/
Authors
Till SeehusenAbstract
No abstract has been registered
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No abstract has been registered
Authors
Simeon Rossmann Merete Wiken Dees Torfinn Torp Vinh Hong Le Monica Skogen Borghild Glorvigen Jan van der Wolf May Bente BrurbergAbstract
Potato soft rot Pectobacteriaceae (SRP) cause large yield losses and are persistent in seed lots once established. In Norway, different Pectobacterium species are the predominant cause of soft rot and blackleg disease. This work aimed to evaluate the potential of real-time PCR for quantification of SRP in seed tubers, as well as investigating the status of potato seed health with respect to SRP in Norway. A total of 34 seed potato lots, including certified seeds, was grown and monitored over three consecutive years. All seed lots contained a quantifiable amount of SRP after enrichment, with very few subsamples being free of the pathogens. A high SRP prevalence based on a qPCR assay, as well as a high symptom incidence in certified seeds were observed, suggesting that current criteria for seed certification are insufficient to determine tuber health and predict field outcomes. Pectobacterium atrosepticum was the most abundant species in the examined seed lots and present in all lots. Consistently good performance of first generation seed lots with respect to blackleg and soft rot incidence, as well as low quantity of SRP in these seed lots demonstrated the importance of clean seed potatoes. Weather conditions during the growing season seemed to govern disease incidence and SRP prevalence more than seed grade. The impact of temperature, potato cultivar and Pectobacterium species on tuber soft rot development were further examined in tuber infection experiments, which showed that temperature was the most important factor in nearly all cultivars. Large-scale quantification of latent infection and predictive models that include contributing factors like weather, infecting bacterial species and cultivar are needed to reduce soft rot and blackleg.