CERES-Maize, which was designed for simulation of hybrid maize (Zea mays L,
), cannot be applied directly to seed-producing inbred maize because of spe
cific field operations and physiological traits of inbred maize plants, We
developed CERES-IM, a modified version of CERES-Maize 3.0 that accommodates
these inbred-specific operations and traits, using a set of phenological m
easurements conducted in Nebraska (NE), and further tested this model with
a set of field data from Michigan (MI), Detasseling (i.e., removal of the t
assels from the female plants) was conducted prior to silking, Male rows we
re removed approximately 10 d following 75% silking, The thermal time from
emergence to the end of the juvenile phase (P1) and the potential number of
kernels per plant (G2) were assessed from field data, and were the only tw
o coefficients allowed to vary according to the inbred line. Rate of leaf a
ppearance of the inbreds was accurately simulated using a measured phylloch
ron interval of 54 degree-days (degrees Cd). Simulation of detasseling and
male-row removal improved grain yield simulation for inbreds, For a set of
35 inbred-site-year simulations, the model simulated grain yield with satis
factory accuracy (RMSE = 429 kg ha(-1)), Average grain yields were 4556 and
4721 kg ha(-1) for the measured and simulated values, respectively, CERES-
IM simulations suggest that the effect of male-row removal on grain yield i
s extremely sensitive to the precise date at which this operation is conduc
ted This would explain the inconsistent effect of male-row removal on femal
e grain yields reported in the literature.