Effects of GA3 application on the inflorescence and yield of ‘Yu Her Pau’ litchi

• We investigate the effect of GA3 on the inflorescence of ‘Yu Her Pau’ litchi.
• We evaluate the capability of GA3 for inflorescence-pruned.
• We experiment the timing of the application of GA3.
• GA3 could decrease the length of inflorescence in ‘Yu Her Pau’ litchi.
• 100 mg L−1 GA3 only increased the ration of leafy inflorescence but did not inhibit inflorescence level.

The goal of this research is to understand the effects of gibberellic acid (GA3) on the size, type of inflorescences and yield of ‘Yu Her Pau’ litchi (Litchi chinensis Sonn.). Additionally, we would like to determine if GA3 application could potentially replace manual inflorescence pruning. During the induction of inflorescence in the 2007–2008 and 2008–2009 study periods, 100 mg L−1 GA3 was applied to the foliar part of the whole ‘Yu Her Pau’ litchi plant every two weeks, for a total of six treatment timings. This was done to compare the handling time with the blooming performance, as well as to compare the yields with the fruit quality of two control groups (one with no treatment and the other with only manual inflorescence pruning). The results indicated that the application of GA3 could increase the ratio of leafy inflorescence (leafy inflorescences/total number of inflorescences) from 10% to 55% (2007–2008) and from 16.67% to 87.5% (2008–2009). Additionally, the length of the inflorescences decreased from 34.78 cm to 26.88 cm (2007–2008), and from 32.13 cm to 21.95 cm. The average number of fruit set per branch was increased from 0.49 (2007–2008) and 0.5 (2008–2009) to 2.10 and 5.18, respectively. And increment did not affect the fruit quality. The fruit set that received the GA3 application was equal to (2007–2008) or better than (2008–2009) manual pruning. These results indicate that the GA3 treatment could effectively replace the manual inflorescence pruning in ‘Yu Her Pau’ litchi.