[Effects of stem numbers per ground area on the quality of standard cut Chrysanthemum morifolium in greenhouse: simulation model]

In order to understand the effects of stem numbers per ground area on the quality of standard cut Chrysanthemum morifolium, an experiment with different cultivars, different stem numbers per plant, different planting densities, and different planting dates was conducted in a greenhouse in Shanghai in 2005 and 2006. The effects of stem numbers per ground area on the canopy leaf area index and external quality of standard cut C. morifolium were quantified using the experimental data. Based on the physiological product of thermal effectiveness and PAR (PETP) the canopy absorbed, a model for predicting the effects of stem numbers per ground area on the quality of standard cut C. morifolium was developed, and validated with independent experimental data. The results showed that with the increase of stem numbers per ground area, the leaf area index increased, whereas plant height, stem diameter, leaf number, and flower diameter decreased. The model gave satisfactory predictions of the quality of standard cut C. morifolium cultivated with different stem numbers and planting density. The coefficient of determination (R2) and relative prediction error (RSE) based on the 1:1 line for fresh mass per stem, plant height, stem diameter, leaf number, flower diameter, and the number of qualified stem harvested per ground area were 0.95, 0.96, 0.94, 0.91, 0.81 and 0.97, and 16.1%, 10.1%, 12.8%, 13.4%, 15.9%, 16.1% , respectively. The model developed in this study could be used for the optimization of light and temperature management for standard cut C. morifolium cultivated with different stem numbers and planting densities in greenhouse.