DETERMINATION OF PRUNUS NECROTIC RINGSPOT VIRUS IN DIFFERENT GENOTYPES OF SOUR CHERRY

In two field trials, the virus-host system "Prunus necrotic ringspot virus - sour cherry" was tested for the first time for the occurrence of quantitative resistance. Earlier, orientative determination of virus concentration on the basis of ELISA extinction values had revealed certain differences between the genotypes. These differences were confirmed by the quantitative ELISA using the standard curve method. Sour cherry cv. Koroser and clone K 30/1 had significantly lower virus concentrations than the susceptible standard Schattenmorelle. This suggests quantitative resistance. Studies on the vegetative growth and on the distribution of Prunus necrotic ringspot virus in single branches also contribute to the assessment of the resistance level of genotypes.