Most widely used training system for commercial fruits like apple, pear, guava is

This system is in between open centre and central leader system wherein central axis is allowed to grow unhindered upto 4-5 years and then the central stem is headed back and laterals are permitted.
It is common in apple, pear, cherry, plum, guava.
After several (3 to 5) main lateral branches are developed, the leader loses its dominance and is allowed to develop similar to the lateral branches. 
Pruning the mature tree involves mostly thinning cuts to allow light to penetrate to lower fruiting wood, although the height of fruit trees should be kept to a height at which fruit can be picked.