Abstract: 【Objective】The aim of the experiment is to study the relationships between light-capture ability and fruiting with different training systems of Nectarine var. Huyou004. 【Method】Four different training systems including central leader form(CL)， open-vase form (OF), Y form (YF) and intersection form (IF) were used in protected cultivation. At the same time，the leaf of the young nectarine trees were sprayed with different concentrations of PP333. 【Result】The results showed that: 1. Extinction coefficient of different forms of canopy was in a descending order of CL>YF>OF>IF, while the Tr and TDP in canopy were YF>OF>IF>CL. The LAIs in IF and OF were not distinct but both were larger than that in YF. The present study also showed that paclobutrazol(PP333) treatment caused the average fruit number per plant and the average fruit weight of CL higher than those in YF, except that CL form produced higher average yield per plant than YF when sprayed with (series concentration as 0-1 250 mg·L-1)PP333.【Conclusion】The young nectarine trees showed the highest light interception ability when treated with CL than the other three training systems. Paclobutrazol treatment has an positive effect on the vegetation and fruiting of four different training systems in some degree.

Key words: Prunus persica var Nectarine, Training system, light interception, fruiting, Protected culture, Paclobutrazol