Abstract
Using 11 or 15 year-old ‘Saijo’ trees, trained to a modified leader system with 4 scaffold limbs, renewal of the trees suffering slightly from a sprouting disorder to a new healthy ‘B type’ strain was attempted by side-grafting on each main scaffold limbs. Two scions were grafted about 50cm above the trunk on each limb. In order to enlarge the shoots from scions as early as possible, girdling and bark inversion were applied to each limb with a 0.8∼1.0 cm width, just above the grafting portions.
Scion shoot growth was promoted by girdling or bark inversion treatment. In the first year of grafting, total contents of carbohydrate in the scion shoot were significantly increased by girdling or bark inversion treatment. The rate of scion shoot enlargement, compared to the old limbs at 2 years after grafting, reached 70∼80% with girdling or bark inversion treatment, which was higher in 20∼30% to control. No significant difference was observed in scion shoot growth between girdling and bark inversion treatments, however, fruit growth on the old limbs to which bark inversion was applied was superior to that on the limbs to which girdling was applied. For promotion of scion shoot growth, the flowering period (early June) seemed to be suitable for the girdling treatment.
