ISHS Acta Horticulturae 525: International Conference on Integrated Fruit Production
BREEDING FOR SCAB RESISTANCE IN APPLE: EVALUATION OF RESISTANCE IN THE GREENHOUSE AND IN THE FIELD |
| Authors: | E. Pauwels, J. Keulemans |
| Keywords: | Malus x domestica, Venturia inaequalis, scab management, susceptibility, Merlijn |
| Abstract:
Developing scab (Venturia inaequalis) resistant apple varieties is one of the most important aims in our breeding program. The aim of this study was to compare the resistance of different progenies in the greenhouse (artificial infection) and in the field (natural infection). The latter progenies were previously selected in the greenhouse. Furthermore we evaluated the field resistance of a less susceptible cultivar, sprayed with different schemes of fungicides. Seven progenies were inoculated in the glasshouse. One of the parents of each progenies was scab resistant. The resistance of the progeny was depending on the resistant parent and probably also on the susceptible one. In 1990 seedlings of 40 different progenies were artificially inoculated in the glasshouse with scab conidia. In 1992, the same was done for 40 other progenies. At least one of the parents carried one or more scab resistance genes (Vf, Va or Vf x Vpoly). The most susceptible seedlings were discarded, which was 50%. The others were grafted on rootstock and after a year in a tree nursery, planted in the orchard. None of these trees were sprayed against scab. In 1997, a year with a high scab pressure, these genotypes were re-evaluated. Several genotypes from different progenies were infected and sometimes symptoms were very severe. Symptoms were different for different progenies. Scab resistance of Merlijn, a cultivar developed at the Fruitteeltcentrum, was evaluated in 1997 using 4 different schemes of fungicides, Merlijn is low susceptible and a reduced spraying scheme satisfies to control scab. | |
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