ISHS Acta Horticulturae 484: Eucarpia Symposium on Fruit Breeding and Genetics
CONSIDERATIONS ON SCAB SUSCEPTIBILITY IN APPLE BREEDING |
| Authors: | J. Keulemans, K. Claes, A. Brusselle, R. Eyssen, E. Pauwels |
| Keywords: | Malus pumila, Vƒ gene, Venturia inaequalis |
| Abstract:
Improved scab resistance is a major objective in apple breeding. In most programmes resistant plants are selected after artificial infection of young apple seedlings. It is hard to obtain reproducible selection results of the same population, infected at different times. Therefore we studied several factors that could affect sporulation on seedlings after artificial infection. In all experiments inoculation conditions were identical. Sporulation was influenced by pre-inoculation factors such as age of seedlings. The concentration of spores (100,000 to 450,000 spores/ml) and the duration of the inoculation period (1 to 3 days) seemed to have only a minor influence on the percentage of seedlings with sporulation symptoms. Twice-infected populations sporulated earlier and heavier than those infected once. Seedlings from an open-pollinated cultivar showed early sporulation when infected with spores collected from that cultivar compared to infection with spores collected from other cultivars. Major differences of sporulation intensity and its development in time were observed according to post-inoculation circumstances: sub-populations of the cross ‘Golden Delicious’ x ‘Priscilla’ showed sporulation percentages of seedlings from 55 to 95 %. This indicates that expression of resistance is partially dependent on environmental factors and not only controlled by genetic factors. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
