Multi-leader, two-dimensional (2D) fruiting walls are becoming popular with growers as an intensive production system. This article deals with the development of the tree’s structure, and setting it up for a long productive life.
Fruiting units (continued from last issue)
The fruiting units are allowed to develop from the base up of each leader.
These start as short laterals and spurs. A spur is a contracted lateral.
Spurs must maintain a terminal vegetative bud that can make leaves and extend the spur the next season.
Full canopies are made up of numerous low vigour fruiting units and spurs that allow transient dappled light to penetrate through the canopy, providing a good environment for renewing the bearing wood and optimum production of fruit of good size, colour and taste.
Bearing-wood management
An understanding of the fruiting habit is essential to maintain good quality bearing wood.
Buds at the basal end of a fruiting unit typically become flower buds. Apricots do not have mixed buds.
After flowering or fruiting, no vegetative buds are left to form leaves and shoots to create new fruiting positions, and the fruiting unit quickly becomes bare. This is called natural floral bud extinction, and to minimize this problem, you need to do these things:
• Maintain a hierarchic growth habit, where the extension growth of the leader is kept dominant initially. When the canopy is fully developed, the tops are pruned soon after harvest at the maximum permissible height (80 per cent of row width).
• During summer, encourage growth of new semi-weak laterals. These will form the next new fruiting units. You also need to stub-cut strong shoots which have an angle of no less than 45 degrees. Remove any strong upright shoots—these will never form good fruiting units.
• Fertigate twice a month and keep chewing insects away, especially from the growing leader tips. Leaders can grow more than one inch a night.
• In autumn, a rigorous renewal of bearing wood is necessary by cutting back into the fruiting wood to stimulate vegetative growth the following season. New growth will form from the rudimentary buds on the piece that is left and also nearby leader.
When the tree canopy is fully developed, usually within three years, impose a post-harvest water stress strategy.
Use regulated deficit irrigation (RDI) after harvest during summer to control vegetative growth and keep the leaders calm.
As well, with good management of sunlight, you can maintain fruiting units that last longer and ensure regular production and consistent fruit quality via controlled vigour in the bearing wood.
See this article in Tree Fruit Sept 2020
You may be interested in an orchard manual: Apricot on Open Tatura
