Maize canopy development in response to increasing plant population density

Improving crop production via adjustment of plant population density (PPD) largely depends on canopy development and light interception. Accordingly, it is essential to investigate the details of how canopy development responds to PPD. A field experiment was undertaken in China in 2009 to examine maize organ development across plant densities i.e. 2, 6, 12 and 20 plants m^–2. Lengths of laminae and sheaths were both increased in lower phytomers due to greater extension duration and decreased in upper phytomers due to reduced extension rate in response to more interplant competition as PPD increased. However, sheath extension appeared less affected by competition stress than lamina extension. Internode length was increased due to higher extension rate at high PPD. This study indicated that leaves and internodes utilized different strategies to cope with interplant competition induced by increased plant density. In addition, the findings can be used in modelling canopy production under different plant densities.