Fig. 3.

Schematic of a mature kiwifruit vine trained on a T-bar support structure. In a standard management scheme, a single trunk is maintained with two horizontally trained relay axes, called leaders, in opposite directions along a support structure (A). New relay axes from these leaders are left to bend under their own weight and eventually tied down to support structures, which are called replacement or parent canes (B). The axillary shoots that grow from these parent canes (C) will produce the fruit. Generally, the parent canes are replaced with one of the vigorous axillary shoots during winter pruning, bringing the vine back to a similar form at the beginning of each season (B). In this kiwifruit vine model, the permanent structure (B) is assumed to be present at the start of the simulation, but the branching pattern of the axillary shoots on a parent cane (D) is a result of the simulation.