Abstract: Product of thermal effectiveness and PAR（TEP）is an important method in the crop growth
simulation models. The growth condition including the longest leaf-length，pseudobulb diameter and the
number of unfolding leaf，is an important index in Cymbidium’s vegetative growth period. The aim of this
study is to investigate the effects of both temperature and photosynthetically active radiation on the growth
condition of Cymbidium hybridum vegetative growth period. According to the characteristic of growth and
development of Cymbidium responding to temperature and light，Cymbidium Hiroshima Golden Cup
‘Sunny Moon’and Cymbidium Great Flower‘Marie Laurencin’were used as experimental materials to
study the growth and development simulation of Cymbidium in the greenhouse by the method of TEP. The
results showed that the predicted results，including the longest leaf-length，pseudobulb diameter and the
number of unfolding leaf，accorded well with the observed ones. The decision coefficient（R2）of predicted values and actual measured values of the cue ball，cormel，sun ball’s longest leaf-length，pseudobulb
diameter，the number of unfolding leaf of the two varieties were respectively higher than 0.98，0.98，0.95；
The regression estimation standard error（RMSE）were respectively lower than 2.06 cm，0.85 mm，1.21；
The relative prediction error（RSE）were lower than 4.8%，2.8%，8.8%. The simulation model is applicable
with few parameters，and can provide an effective method to predict the growth condition of Cymbidium’s
vegetative growth period and decision support for the light and temperature management of greenhouse
Cymbidium’s production.

Key words: Cymbidium hybridum, vegetative growth period, growth condition, TEP, stimulation model