Open access publications in the SLU publication database

Abstract

Consumer interest in organically grown fruit appears to have increased considerably in recent years but the organic apple growing in Sweden cannot match the demand. One objective of this thesis was to study conversion of an orchard with 'Aroma' and 'Karin Schneider' from IFP to organic production. The accumulated yield for both cultivars was slightly lower in the organic sections compared to the IFP-grown sections, due mainly to a lower number of fruits while fruit size remained the same. In organic sections, 10% of the fruit was damaged by scab but less than 1% in the IFP sections. Aphids and NTG (noctuids, tortricids and geometrids) inflicted the highest amount of insect damage and this damage was higher in the organic sections. No major treatment effects were found in fruit covering colour, ground colour, firmness, sugar content or malic acid content. Two observation trials with apple scab-resistant cultivars and one with cultivars suitable for organic production of fruit for industrial use were also carried out. In Trial I, the most productive cultivars were 'Bio Golden' and 'Topaz', and in Trial II 'Vanda' and 'Scarlet O'Hara'. The fall-ripening 'Rubinola' and the late-ripening 'Scarlet O'Hara', which keeps well in storage, seem to be suitable for organic growing in our climate. 'Rajka' is interesting since it appears to be resistant against the rosy apple aphid. In Trial III with industrial cultivars, 'Blenheim Orange', 'Bramley', 'Holsteiner Cox', 'Ingbo', 'Queen' and 'Vanda' appear to be promising due to high levels of tree and fruit resistance to pests and diseases, and production of fruits suitable for processing. A consumer evaluation of scab-resistant apple cultivars was also performed. The consumers evaluated five cultivars each. Each cultivar was scored for appearance, texture, juiciness, taste and overall impression. All quality attributes were positively correlated when calculations were performed across all consumer scores, with overall impression and taste having the strongest association. 'Rubinola' and the Baslgård selection 'K:1160' emerged as the best liked cultivars overall. Minimum number of consumers needed to obtain reliable results was determined by computer simulations indicating that the variation became stabilized already with 50 consumers.