Studies on the Fruit Thinning of Kiwifruit

1. Influence upon Fruit Shape by Difference of Flower Bud Position

Abstract

It is not obvious which flower buds on each bearing shoots should be kept to obtain fruits of good quality. We studied the influence of position of flower buds on fruit shape, using weak shoots which growth has stopped and moderate growing shoots, both bearing five flower buds.
Results as follows:
1. Flower buds in the center and those near the center were heavier, and larger diameter.
2. The proportion of blooming was highest on the fourth day of blooming on moderate shoots. Blooming was earlier for flower buds in the center and near the center.
3. Longitudinal diameter of all fruits 3 to 5 weeks after full bloom reached 70 to 80% of their final longitudinal diameter. Particularly, the basal fruits showed higher daily increase in diameter in the early period.
4. Basal fruits on weak shoots and fruits in the center and neighbouring fruits on moderate shoots grew larger, while apical fruits grew less. Basal fruits tended to be flatter, and apical fruits tended to be more cylindrical. Fruits in the center borne on moderate shoots tended to have higher green value compared to basal fruits. No difference was found in Brix and hardness of the fruits according to the fruiting position.
5. From these results, it can be assumed that in order to produce fruits of good quality, flower buds on either end should be removed regardless to the growth of fruit bearing shoots in the early period. Early disbudding and/or deblossoming would reduce working hours and increase working efficiency.