Estimating Useful Diversity in the Norwegian Core Collection of Apples

To be able to exploit the diversity in clone archives, estimates of diversity of useful traits are required. We analysed 106 apple cultivars for dry matter, alcohol insoluble substance (AIS), total soluble solids, galacturonic acid, malic acid, total phenols, and selected major phenols in the fruit flesh and fruit skin. A set of 25 cultivars was tested for three years whereas the other cultivars were tested for one year only. For phenols the differences between cultivars were generally much larger than the differences between years. In another part of the project, 52 cultivars were tested for susceptibility to apple scab and powdery mildew. No scab was observed on 'Priam' and 'Rondestveit'. Powdery mildew was observed on all cultivars, although at a very low level on several cultivars. Interestingly, the content of quercetinrhamnoside in the fruit skin was very high in many scab resistant (Vf) cultivars.