INDEXING FOR APPLE PROLIFERATION IN ROOTSTOCKS
When rooted layers of mother plants and the layer - indicator combination were sectioned into scions from base to tip, and each scion was grafted with the indicator Golden Delicious, in order to determine in which parts of the plant the disease could be detected, the results were inconsistent. In the case of the layers, sometimes only the root part developed symptoms, and otherwise the disease could be detected even in areas above the mid-section of the sectioned shoot. However, even four years after the infection of the mother plants, the disease could not be detected in all layers.
In some plants it was possible to detect proliferation in almost all sections from base to tip by indexing the rootstock - indicator combination.