Effect of cincturing on growth and flowering of lychee over several seasons in subtropical Queensland

Abstract

The effects of autumn cincturing on vegetative flushing and incidence of flowering of 2 lychee (Litchi chinensis) cultivars (Bengal and Tai So) were investigated over 1-3 years at 8 sites in subtropical southern Queensland. Cultivars at these sites varied in the level of natural vegetative dormancy in winter (3-100% of terminal branches) and flowering in spring (0- 100% of terminal branches). There was a strong correlation between percentage flowering (y) and the level of dormancy (x) in the 1-2 months prior to floral initiation (y= 8.8 + 0.83~; r=0.89, P<.001). Cincturing increased flowering by 40-800% in trees that would have flowered poorly in spring (< 70¦/o), but had no significant effect (P> 0.05) on flowering in trees that would have bloomed profusely (70-100%), provided trees were adequately fertilised and actively flushing after harvest. This was shown by the relationship, y= 899 - 23.0x+ 0.14x2; r= -0.96, P<0.001), where y is the percentage change in flowering after cincturing and x is the percentage flowering in control trees. Cincturing reduced or delayed flowering if nutrition was not maintained. It is concluded that trees to be cinctured should be adequately fertilised and complete a significant vegetative flush after harvest.