FRUIT TREE SIZE AND ARCHITECTURE

Fruit tree size control and tree architecture in order to improve the efficiency of the hand labor has been achieved for centuries through pruning, and the highest sophisticated expression was reached in the 18^th century by La Quintinye, gardener of Louis XIV of France.
During that time, many tree training systems were developed (palmette, horizontal and vertical cordon, fan shape) mainly for ornamental purposes.
Due to the high efficiency and the increased fruit quality of these training systems, some were introduced into the commercial fruit industry.
Palmette, with all its variations, is probably the most important application of the historical tree training systems singled out by the royal orchardists and adopted in commercial orchards, followed by cordons.
These have been adapted to control tree size and shape.
Based on the fundamental studies of R.G. Hatton at East Malling (UK) between 1920 and 1938, tree size control was obtained through the adoption of dwarfing rootstocks in combination with training systems and pruning techniques.
More interest was attached to both tree size and architecture starting from the 1970s.
Numerous studies showed great variability of these traits in different fruit species.
During the last decades, genetic control of tree size and alternative tree architectures have been important objectives of several breeding programs around the world.
Three main genetic traits for tree size control are dwarf, semi dwarf, and compact.
Unconventional tree architectures include columnar and weeping habits.