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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.

2017

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Abstract

Tunnel production of sweet cherry results in higher yields of larger fruit than in the open. When cherry trees were grown under tunnels in Norway, fruit cracking was higher in a year when soils were saturated and when 20 ppm gibberellic acid was applied at straw color. In this study we evaluated the effect of soil moisture on fruit cracking under tunnels. In 2013, a trial on mature 'Sweetheart'/'Colt' trees growing under high tunnels was initiated. Each plot consisted of 8 trees, spaced 2×4 m apart with 'Lapins' as guard trees. Experimental design was a split-plot design with or without 20 ppm GA3 application at straw color; and three drip irrigation regimes (zero, deficit and full based on evapotranspiration). During the season, soil water content was monitored weekly. Due to unfavorable weather conditions during bloom time, crop loads were lower than normal. Average fruit sizes were large and GA3 application at yellow straw color resulted in small increases in average fruit diameter and fruit weight with all three irrigation treatments. Fruit cracking was very variable and occurred almost exclusively at the distal side of fruit and not on the stem side. GA3-treated fruit cracked slightly more than untreated fruit. There were no differences in fruit cracking due to irrigation scheme.

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Abstract

Flowering is one of the most important factors in plant fertility. Fruit set in fruits is directly influenced by the beginning, sequence, flow, duration and abundance of flowering. The objective of this study was to evaluate the variability of flowering in 41 ‘Oblačinska’ sour cherry (Prunus cerasus L.) clones, and to recommend earlyflowering genotypes for growing in warmer locations where late spring frosts are rare, and some late-flowering clones for sites more susceptible for spring frost. Results from the three years period (2004-06), showed that ‘Oblačinska’ sour cherry clones flowered in a fixed sequence each year. Average for clone VII/2N, which flowered the earliest, was April 8 and petal fall took place by April 21, whereas clone III/1 bloomed last on April 14 and petal fall took place on April 25. Statistical analysis showed that almost all sub-phases of flowering were under the significant influence of both ecological and genetic factors. Besides, ecologic factors had the highest impact to the variability of beginning of flowering (79.8%), full bloom (76.8%), petal fall (80.2%) and duration of flowering (85.56%). Clones III/1, III/13, V/6 and V/2 were considered as late flowering, whereas clones VII/2N, VI/27, VI/28 and IX/P were early flowering, taking place five days earlier then previous group.

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Abstract

In order to investigate the genetic structure and differentiation among north and south European apple germplasm, 141 apple accessions maintained in ex situ collections in Norway and 110 traditional and international apple accessions from Bosnia and Herzegovina (B&H) were analyzed using 8 microsatellite markers. Bayesian analyses, based on the microsatellite data, grouped most of the accessions into two major clusters. The first cluster consisted mainly of traditional and international B&H accessions, as well as Norwegian accessions derived mostly from foreign or formal breeding programs (‘James Grieve’, ‘Katja’, ‘Summerred’, ‘Bramleys Seedling’, ‘Elstar’, ‘Katinka’, ‘Belle de Boskoop’, ‘Jacques Lebel’, etc.). The second cluster consisted almost exclusively of traditional Norwegian accessions. Further analyses divided each cluster into two sub-clusters. Cluster 1.1 included Norwegian accessions derived from foreign or commercial breeding programs, international cultivars and B&H accessions introduced from Europe and North America during the rule of Austria-Hungarian Empire. Cluster 1.2 included traditional B&H accessions introduced during the reign of Ottoman Empire. Cluster 2.1 and 2.2 consisted mainly of traditional apple accession from Norway. The results obtained indicate a clear genetic structure and differentiation among north and south European apple germplasm, presumably due to climate adaptation and selection.

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Abstract

Perennial fruit crops phenology such as cherry is an ideal bio-indicator of climate change due to their long-lasting features, in particular, dates of flower opening and full bloom. This implies i) the use of several generations of cherry trees/orchards and ii) the use of the same original cherry cultivars, which existed as bearing trees and were replanted after the orchard had been grubbed. A comparison of available definitions of phenological stages in cherry previously used independently throughout Europe showed overlaps and shortcomings; hence, harmonisation was reached in this respect in the COST Cherry FA 1104 working group 2 (cherry phenology and climate change) based largely on the acceptance of the BBCH scale. This contribution presents the agreed phenology stages in both visual and wording evidence. Similarly, this contribution presents the agreed cultivars to be monitored in future for phenology and climate change effects for harmonisation. For sweet cherry, this EU-wide harmonisation includes ‘Burlat’, ‘Cristobalina’ and ‘Rita’ as early, ‘Stella’ and ‘Van’ as medium flowering and ‘Sweetheart’, ‘Regina’ and ‘Bigarreau Noire de Meched/Germersdorfer’ for late flowering cultivars for climate change effects. For sour cherry, this harmonisation resulted in ‘Meteor korai’ and ‘Anglaise Hative’ for early flowering, ‘Chrisana Pandy’ and ‘Erdibotermo’ for medium flowering and ‘Schattemorelle’, ‘Iiva, Ujfehrtoifurtos (Balaton)’ for late flowering.