Effect of leaf to fruit ratio on fruit growth of kiwifruit ( Actinidia deliciosa)

Abstract

Fruit size of kiwifruit was not reduced at low leaf-fruit ratios (less than 2:1) on non-girdled laterals because translocation from other parts of the vine could meet any shortfall in the local supply of carbohydrate in the fruiting lateral. However, girdling and 14 C-tracer studies showed that the minimum leaf:fruit ratio that is required to support fruit growth in the kiwifruit lateral, without import of carbohydrate, is 2:1, or approximately 225 cm 2 of leaf area per fruit. Fruit load did not affect the specific leaf weight, photosynthetic rate or stomatal resistance of the leaves on either intact or girdled laterals. Indications of an inhibitory effect on fruit growth by large leaf areas on intact laterals, which was reversed when girdling treatments were applied, may relate to the interactions of growth substances in determining sink strength.