ISHS Acta Horticulturae 734: VIII International Symposium on Plum and Prune Genetics, Breeding and Pomology
RECENT PROGRESS IN NORWEGIAN PLUM BREEDING |
| Authors: | S.H. Hjeltnes, L. Nornes |
| Keywords: | plum breeding, selection, Sharka, mating design, germination, fruit set, thermoterapy |
| Abstract:
The plum breeding programme at Njøs lost a lot of progress when Sharka was discovered in our collection of plum cultivars and nearly all plum trees at the station were grubbed during the years 1998 to 2001. Part of the most valuable material was rescued by using thermotherapy, and subsequent tip-grafting on virus-free rootstocks. In 2001, a new series of hybridizations started, at a North Carolina design II, with 7 mother cultivars and 4 pollen cultivars. The crossings have been made in a plastic tunnel on trees trained in super spindle. Crossings in plastic tunnels are made 3-4 weeks before flowering in open air, where the crossings are made in mobile “tents” covered with agryl. We have experienced low fruit set with ‘Ruth Gerstetter’, which was expected as the pollen had poor germinability. On the other hand, ‘Excalibur’ and ‘Reine Claude Souffriau’ resulted in high fruit set. Germination of seeds from young trees of ‘Jubileum’, ‘Opal’, ‘Reeves’ and ‘Victoria’ has been high, in contrast to seeds from old trees of ‘Reine Claude d’Oullins’ and ‘River’s Early Prolific’. So far, one selection is tested by growers, 14 selections are tested in our own experimental orchards, and 2000 seedlings are in the process of seedling evaluation. | |
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