genetic parameters so that simulated values compare well with
observed ones. The genetic coefficients used in the CERES models
characterize the growth and development of crop varieties differing
in maturity. Calculating the genetic coefficients of cultivars is
the first step in the conventional use of the CERES models. Similar
initial values for coefficients are firstly supplied to run the model
according to cultivar characteristics, then a method of the trial and-
error type hypothesis in the study is used to reduce the difference
between simulation and observation for flowering duration,
maturity duration, grain yield, grain weight per 1000 and harvest
index, and get the most matching values for these cultivars.
In this study, the experiment dataset of one year with one rice
cultivar is used to calculate genetic coefficient in each station, and
evaluate crop model and application. These cultivars were grown
for at least two years in the same station. The experiment of one
year with one typical rice cultivar in each station was used to calibrate
and calculate genetic coefficients, and others are used for
validating the CERES rice model. Information of rice fields observed
in experiments for calibration and validation of CERES rice model is
represented in Table 2.