CLONAL SELECTION OF M 9 APPLE ROOTSTOCK AND INFLUENCE OF VIRUSES ON POMOLOGICAL VALUE

After heat treatment to inactivate viruses, several M 9 rootstock thermonumbers (clones) showed differences in behaviour in the stoolbed (shape of leaves and twigs, productivity, rooting, lateral branching, etc…). Observations in various stoolbeds showed that these differences are sometimes very important.

Orchard trials with Golden Delicious, Cox’s Orange Pippin and Belle de Boskoop grafted on different M 9 clones do not allow very clear conclusions to be drawn because the performance of the M 9 clones varies from one trial to another.
If we take the mean result of all the trials, the differences between the "good clones" are not very important.
On the other hand, the productivity of virus-free material is much higher than that of non virus-free material.

Workshop on Clonal Selection in Tree Fruit

G.L. Gilles, H. Bormans, P. Van Laer

https://doi.org/10.17660/ActaHortic.1986.180.7