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.
2018
Authors
Anita SønstebyAbstract
No abstract has been registered
Authors
Anita SønstebyAbstract
No abstract has been registered
Authors
Anita SønstebyAbstract
No abstract has been registered
Authors
Anita SønstebyAbstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
European plums (Prunus domestica L.) blossom abundantly most years and often set too many flowers. If these excessive numbers of fruitlets remain on the trees until harvest, the crop would consist of small, unmarketable fruits of low fruit quality. Thinning agents like ammoniumthiosulphate (ATS), sulphur and soya oil desiccate flowers, especially stigma, which is the most sensitive tissue part of the flower. This way, the main effect of blossom thinning treatments is the disruption of pollination and fertilization. Thinning trials were conducted at a commercial orchard near the shore of the Hardangerfjord near Nibio Ullensvang, western Norway (60.2°N) on mature ‘Jubileum’ trees, all grafted on ‘St. Julien A’ rootstock. The trees were treated with 0.4, 0.8, 2 and 4% sulphur; a mixture of 0.4% sulphur + 2% soya oil and 1.5% ATS (liquid and powder formulations), at full bloom. All treatments were compared with hand-thinned and unthinned trees which were used as a control. Experimental trees were sprayed to the point of run-off with a hand sprayer during May 2008 and 2009 at full bloom. Flower thinners were efficient at relatively low temperatures which is a benefit in a cooler climate. In 2008 all thinning treatments reduced fruit set compared to unthinned controls for all cultivars. Sulphur and soya oil, both alone and in combination, were significantly less effective than ATS. In 2009, fruit set was higher and the effects of all thinning agents were lower. Fruit set decreased with increasing sulphur concentrations, but fruit thinning was not sufficient, even at the highest concentration. Both the liquid and powder formulations of ATS gave the same thinning effects. For all thinning treatments, both significant yield reductions and fruit weight increment were noticed during the experimental period. Fruit over color and soluble solids were generally higher and increased significantly with lower crop load, while fruit firmness (Durofel) and total acidity were less affected. In conclusion, different concentrations of sulphur had a moderate thinning effect and are not recommended for use as plum thinners under these conditions. Instead, 1.5% ATS application, (liquid and powder) applied at full bloom, resulted in adequate thinning of ’Jubileum’ plums under cool mesic northern climatic conditions.
Authors
Mekjell MelandAbstract
No abstract has been registered
Abstract
Due to their Mendelian inheritance, microsatellites or SSRs (simple sequence repeats) can readily be used for parentage analyses of pear seedlings, thus revealing the female and male parents of the plant. However, in cases where obtained pear seeds display low viability, conducting a parentage analyses on the pear seeds themselves could be used in order to identify the male parent (successful pollinator). In this study, batches of seeds were extracted from fruits of the triploid ‘Ingeborg’ pear (‘Conference’ × ‘Bonne Louise’), the main commercial pear cultivar in Norway. Mature pears were collected from eight commercial pear orchards located in Ullensvang, at 60° North and seeds were collected. Genomic DNA was subsequently isolated from the obtained seed batches and genotyped using 12 microsatellite markers. The same markers were also used for the genetic characterization of ‘Ingeborg’ and five pear genotypes used as pollinators in the sampled orchards (‘Clara Frijs’, ‘Herzogine Elsa’, ‘Anna’, ‘Colorée de Juillet’ and ‘Belle lucrative’). The obtained SSR profiles were used in paternity analyses, as well as for gene assignment analyses. Both approaches identified pear ‘Clara Frijs’ to be the most successful pollinator in most of the sampled orchards. Subsequent S allele genotyping of ‘Ingeborg’ and five pear genotypes used as pollinators in the sampled orchards revealed that the preferential pollination by individual genotypes was not caused by gametophytic incompatibility or semi-compatibility.