Dimethyl Piperidinium Chloride(DPC) Regulation of Canopy Architecture and Photosynthesis in a Cotton Hybrid in an Arid Region

To investigate the effects of different concentrations of dimethyl piperidinium chloride(DPC) on canopy architecture and photosynthesis in two hybrid cotton varieties,we conducted an experiment with two levels of growth regulator compare with two traditional varieties.With mild growth regulator and in cotton hybrids Biaoza A1 and Shiza 2,we observed a significant increase in internode length above the sixth internode which is the starting point of the canopy,a higher and slower decline in leaf area index,larger leaf angle,greater light interception,larger diffuse non-interceptance,and a higher canopy photosynthetic rate with longer duration.This meant that photosynthetic accumulation and yield increased significantly.In Xinluzao 13 and Xinluzao 36 the internode length above the sixth internode changed slightly,while the peak in leaf area was index higher,the diffuse non-interceptance was greater,leaf area index declined quickly and less light was intercepted,the group photosynthetic capability was significantly weakened,and the yield consequently decreased.The traditional growth regulator resulted in the deterioration of hybrid cottons' canopy structure,fall of the group photosynthetic capacity and yields.It showed that the mild growth regulator thus contributed to improve the efficiency of hybrid cottons' canopy structure and photosynthetic capability,and was thus beneficial for improved growth and cotton yield.