COMPARATIVE TRIALS ON PEACH SEEDLINGS AS ROOTSTOCK FOR INTENSIVE NECTARINE ORCHARDS
Some of these rootstocks were selected by the Pomology Institute of Pisa University from among those which had induced differences in tree vigour in previous trials.
After five years of observations, the vigour of trees, evaluated as trunk sectional area, was found to be influenced by the rootstocks.
Trees grafted on to A III showed the highest values (similar to those of the commercial seedlings from Bulgaria) while a diminishing order of vigour was observed on A V, Rutgers Red Leaf and finally Siberian C. The trunk sectional area on the last was about 48 % less than that on A III.
The trees were most uniform when grafted on PS C 12 (10 % coefficient of variation), and less so on the other rootstocks. They showed the lowest uniformity on Rutgers Red Leaf and Harrow Blood (34 % coefficient of variation).
The total number of fruits per tree did not differ significantly from one rootstock to another but during 1976 and 1977 trees grafted on A III, PS C 12, PS C 10 and Harrow Blood produced more than the others.
Siberian C gave the highest value of tree efficiency (fruit number/cm2 of trunk sectional area) followed by Harrow Blood and Rutgers Red Leaf.