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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.

2022

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Abstract

An intensive planting of ‘Celina’ pears on quince ‘Adams’ rootstock was established in May 2015 at NIBIO Ullensvang, western Norway. Five training systems (super spindles, trees with two leaders parallel to the row directions, slender spindles, and V-hedges of trees with 2 or with 4 leaders) were evaluated. Row distance was 3.5 m, and planting distance was 1.0 m except for super spindle trees and V-hedge with two leaders (0.5 m). Cultivars ‘Anna’ and ‘Fritjof’, used as pollinizers, were evenly distributed in the orchard and had good overlapping in flowering time. To get a faster establishment, the trees were headed back in winter 2016 when the formation of the different training systems was started. The first fruits were harvested in 2018. Due to unfavorable pollination conditions, fruit set in 2018 was very low. Average yields varied between 2.7 t ha‑1 for the super spindle trees to 10 t ha‑1 for the spindle trees. As a result of ample flowering and optimum pollination conditions, fruit set in 2019 was excellent, and average yields varied between 17 t ha‑1 for the 2-leader trees planted parallel to the row direction to 47 t ha‑1 for the 2-leader V-hedge trees. Fruit size was inversely related to fruit number per tree. Fruit weight depended on crop load per canopy volume and varied between 130 g for the two smallest trees (super spindles and 2-leader V-hedge system) and 180 g for the 2-leader trees planted parallel to the row direction. Soluble solid contents were high (11% on average), with no differences between training systems. After three cropping years, the spindle trees and V-hedge with 4 leaders per tree were the most productive systems per tree. However, the super spindle and 2-leader V-hedge system with twice the number of trees were the most productive systems per hectare.

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Abstract

Using modern analytical techniques, a comprehensive study of the chemical composition of fruits from apple cultivars grown in Western Norway during 2019 and 2020 was done. Metals, sugars, organic acids, antioxidant tests, and polyphenol content have been observed. In all investigated samples, the most dominant sugars were glucose, fructose, and sucrose. Among 11 tested organic acids, the dominant was malic acid, followed by citric and maleic acid. The most common metal was potassium, followed by magnesium and zinc. The quantification of polyphenols showed that among the 11 quantified polyphenols, chlorogenic acid, quercetin 3-O-rhamnoside, quercetin 3-O-glucoside, quercetin, and phlorizin were the most abundant. A detailed study of the polyphenolic profile of nine investigated apple samples provided 30 identified polyphenolic compounds from the class of hydroxybenzoic and hydroxycinnamic acids, flavonoids, and dihydrochalcones. In addition to the identified 3-O-caffeoylquinic acid, its two isomers of 5-O-caffeoylquinic acid and three esters were also found. Present polyphenols of the tested apples provided significant data on the quality of Norwegian apples, and they contribute to the distinguishing of these apple samples.

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Abstract

Denne rapporten omhandlar resultat frå kartlegging av næringsstatusen i norske eplehagar. Jord,- blad og fruktprøvar vart samla inn frå ulike eplehagar på Aust- og Vestlandet med variasjon i jordart, innhald og type organisk materiale i åra 2018-2020. Føremålet var å studera samanhengane mellom plantefysiologiske sider i epletreet relatert til jorda, treveksten, avling og fruktkvalitet. Resultat frå det treårige studiet om verknaden av gjødselpraksisar på opptak av mineral i blada, avling og fruktkvallitet hjå ulike eplesortar frå fire regionar er samla i denne rapporten. This report is summarizing results from a survey analyzing the nutrient levels in fruit trees and soil in four fruit growing regions in Norway during the seasons 2018-2020. The aim was to study the relationship between main plant physiological principles in the tree, related to the soil, tree growth, yield, fruit quality, and fruit storage. The results of a three-year study of apple tree fertilization practices on orchard soil fertility, leaf mineral composition, apple tree yields and fruit quality of several apple cultivars in four main apple producing regions in Norway are compiled in this report.

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Abstract

This study evaluated the effective pollination period (EPP) in four European plum (Prunus domestica L.) cultivars (‘Mallard’, ‘Edda’, ‘Jubileum’, and ‘Reeves’) during two years (2018–2019) under the environmental conditions in western Norway. The pollination of plum cultivars was carried out one, three, five, seven, and nine days after anthesis (DAA) with a pollen mix of two compatible cultivars (‘Victoria’ and ‘Opal’). Initial, middle-season, and final fruit set was recorded after one month and two months after pollination and just before the harvest, respectively. On average from both years cultivar ‘Jubileum’ had the highest fruit set when pollinated one, three, five, seven, and nine DAA (33.23%, 30.83%, 8.47%, 3.08%, and 1.15%, respectively), which was more than two folds higher fruit set than in the other studied cultivars. Cultivar ‘Jubileum’ showed significantly reduced fruit set between pollination on five and nine DAA, while cultivars ‘Mallard’, ‘Edda’, and ‘Reeves’ had markedly reduced fruit set if pollinated three to five DAA, implying that the EPP in ‘Jubileum’ was five days while in the rest it was three days. Variation of weather conditions during the flowering period in both years did not have a major effect on the receptivity of stigmas in the studied plum cultivars, which means that the existing differences in the length of EPP is maternal-genotype dependent.

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Abstract

Compatibility and synchrony between specialized tissues of the pistil, female gametophytes and male gametophytes, are necessary for successful pollination, fertilization, and fruit set in angiosperms. The aim of the present work was to study the development and viability of embryo sacs, as well as fertilization success, in relation to the fruit set of the cultivars ‘Mallard’, ‘Edda’, ‘Jubileum’, and ‘Reeves’, under specific Norwegian climatic conditions. Emasculated, unpollinated, and open-pollinated flowers were collected at the beginning of flowering, and on the 3rd, 6th, 9th, and 12th days after flowering, from all four plum cultivars over two years (2018/2019). Ovaries were dehydrated, embedded in paraffin wax, sectioned, stained, and observed under a light microscope. Results showed the existence of synchronization between successive phases in the development of the embryo sac and individual phases of flowering. All plum cultivars had higher percentages of viable embryo sacs, fertilized embryo sacs, and fruit set in 2018 than in 2019. These differences may be related to the very low temperatures during the post-full-flowering period in 2019, and to the low adaptation of some studied cultivars to unfavorable conditions. In our study, the cultivar ‘Jubileum’ showed the highest percentage of viable embryo sacs, fertilized embryo sacs, and fruit set compared to other cultivars, i.e., the best low-temperature adaptation.