Abstract: This paper reported that the sweet pepper(Capsicud frutescens L. var. grussum Baily)cultivated in film covered hothouse kept 4600 leader branches per 1000 m², and diffenent training methods were compared. The result of experiment showed that the yield of plannt 2 with leader branches was at least 13.6% higher than that of plant with 4 leader branches. The method of remainning 2 leader branches made population structure equitable and gave appropriate L. A. I. (about 4), meantime increased the amount of root system per unit area by 35%. There were significantly positive correlation between the harvest in the plot and the increment of root. The paper suggested that studying of population structure of crops should not be limited on aerial growth, the accumulative amount of root system and their distribution also shouldn’t be ignored.

Key words: Sweet Pepper, Number of leader branchs