Effect of GA₃+CPPU induction time on loquat pit development

The flower organs and fruit seed of loquat,Zhao Zhong No.6,were studied for their growth and development with the induction of 400 mgL-1 GA3 and 20 mgL-1 CPPU at different growth stages.The study was aimed to understand the mechanism involving the parthenocarpic development,as well as to determine the appropriate time for the induction.The results showed that 100.0% seedless rate was achieved when the induction took place in the flower budding stage,while 0% if the induction was done after anthesis or on the control plant.No significant differences on pit weight,number of pits in young and mature fruit or seed germination rate were found on plants induced after anthesis and the control.It appeared that GA3+CPPU induction on the flower bud enhanced the dichogamy and herkogamy resulting in significant reduction,or total absence,of pollination and fertilization.Without formation of embryo,the loquat fruit would not form pit.Therefore,the time for GA3+CPPU induction in order to produce seedless loquat fruits would be during its budding stage before pollen fertilization.