Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2020
Sammendrag
Identification of stocktype attributes that speed up field establishment has potential to reduce rotation time of Christmas tree productions. Such morphological and physiological attributes can be targeted in the nursery production. This study tested the effects of container type and nursery seedling density on stocktype attributes at planting and the effects of these on field performance over two years in Abies lasiocarpa and A. nordmanniana Christmas tree stock. Nursery conditions had a considerable impact on seedling attributes at planting. Although sets of these correlated stocktype attributes contributed to forecast field performance, the predictive power was low. No simple relationships were found between plant biomass, stem diameter or height at planting and biomass at final harvest in either of the two species under the range of stocktype variation and field conditions tested. Contrary, stem diameter and stem height at planting explained some of the responses in stem diameter and height after two years in the field. Thus, any target seedling approach would have to be based on a combined set of stocktype attributes exploring more productive stocktypes. The differences observed between stocktypes were largely due to size differences and ontogenetic drift, and stocktypes converged towards a similar field phenotype over time.
Forfattere
Abdelhameed Elameen Vera M. Kosman Mette Thomsen Olga N. Pozharitskaya Alexander N. ShikovSammendrag
Det er ikke registrert sammendrag
Forfattere
Habtamu AlemSammendrag
The objective of this paper is to examine the economic performance of crop-producing farms accounting for unobserved heterogeneity,environmental variables, and regions. The empirical analysis was based on a translog cost function and unbalanced farm-level panel data for 1991–2013 from the 455 crop-producing farms with 3,885 observations (1,004observations from the central region and 2,881 observations from the eastern region). We found that the mean minimum costs were about 93% and 92% of the actual costs for crop farms in the central and eastern regions, respectively.The marginal effects of crop rotation, land tenure, off-farm activity, direct government support, and experience were positively associated with crop farm economic performance. The marginal contribution of these variables on economic performance increased in the years 2000–2013 compared with the years 1991–1999 in both regions.
Forfattere
Habtamu AlemSammendrag
Det er ikke registrert sammendrag
Forfattere
Till SeehusenSammendrag
Det er ikke registrert sammendrag
Forfattere
Till SeehusenSammendrag
Det er ikke registrert sammendrag
Forfattere
Daniel Muluwork Atsbeha Ola Flaten Hanne Fjerdingby Olsen Nils Petter Kjos Alemayehu Kidane Adrijana Skugor Egil Prestløkken Margareth ØverlandSammendrag
Det er ikke registrert sammendrag
Sammendrag
In order to identify successful pollinizers of plum cultivars ‘Edda’ and ‘Opal’, 60 mature open pollinated fruit were collected from these two cultivars in autumn 2017. The fruits were harvested in three different orchards located in Ullensvang, the main fruit production area in Norway. After the harvest, kernels were separated from the fruit and used for the extraction of single embryos located within each kernel. At the same time, leaves were collected from the plum cultivars ‘Edda’ and ‘Opal’, as well as from all other plum cultivars present at the location and nearby orchards (‘Mallard’, ‘Jubileum’, ‘Reeves’, ‘Avalon’, ‘Valor’, ‘Cacanska Lepotica’ and ‘Herman’). DNA extraction was carried out for the embryos and leaves, and were used for genotyping using seven microsatellite markers. The microsatellite data were used for conducting paternity analyses based on a log likelihood ratio, where the fingerprint information from the leaves were the possible pollen donors available at the location. The results revealed within all examined orchards that the most successful pollinizer of ‘Edda’, a self-sterile cultivar, was ‘Opal’. The most successful foreign pollinizer of ‘Opal’ was ‘Mallard’. However, more than two thirds of embryos extracted from ‘Opal’ fruits did not present any alleles not already identified in ‘Opal’, which was expected considering that this plum cultivar was known to be self-fertile. European plums are hexaploid making its allele callings and paternity tests rather complicated. However, the approach used in this study gave clear answers regarding the most successful pollinizers.
Sammendrag
The triploid pear cultivar ‘Ingeborg’ is currently the main commercial pear cultivar grown in Norway. However, fruit set and subsequent yields of this cultivar have proven to be variable and overall rather low. In order to promote the fruit set, different bioregulators were applied during and after bloom and compared with an untreated control. Investigations were done during the period 2017-2018, at NIBIO Ullensvang, western Norway. Different dosages of both gibberellins (GA3, trade name GIBB 3, 10% active ingredient (a.i.) and GA4/7, trade name Novagib®, 1% a.i.) were applied at full bloom and at petal fall. Additional applications of the growth retardant prohexadioneCa (trade name Regalis®, 10% a.i.) were applied twice, when bourse shoots had 3-5 leaves and after one month later. Ethephon (Cerone (480 g a.i. L-1)) was applied three times starting about 7 days after petal fall with ca. 7- to 10-day intervals. All gibberellin applications significantly increased fruit set compared to the untreated control. One single application with GA3 (3 g ha-1) almost tripled the fruit number per 100 flower clusters when compared with the control (136 and 46, respectively). The yield response was similar (16.8 to 9.6 kg tree-1, respectively). Similar results occurred with one application of GA4/7 (12 g ha-1) with the same crop load level, and the fruit weights were similar to the control (130 g). Prohexadione-Ca treatments significantly reduced shoot growth of the pear trees. Two treatments with 125 g ha-1 or one treatment of 250 g ha-1 reduced the growth by ~35% but had no significant effect on fruit set and yield. The multiple ethephon applications (275 mL ha-1 in total) had no effect on both set and shoot growth, and return bloom compared to the untreated or gibberellin treated trees.
Forfattere
Jan Emblemsvåg Nina Pereira Kvadsheim Jon Halfdanarson Matthias Koesling Bjørn Tore Nystrand Jan Sunde Celine ReboursSammendrag
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