Abstract
The proposed study was undertaken to develop a simple mechanistic growth model, WHEATGROW, to simulate
the growth, development and grain yield of wheat as affected by sowing date under semi arid conditions of
Pakistan. Measurement of crop growth and environmental variables were made to establish the causes
underlying the variation in crop yield associated with three sowing dates (10 Nov., 25 Nov., and 10 Dec.).
Simulated grain yield output was 60 % in 10 November, 54 % in 25 November, 38 % in 10 December and total
dry matter accumulation was 73 % higher in 10 November, 36 % in 25 November, 12 % in 10 December.
Comparisons of simulated and measured quantities indicated satisfactory performance of the model, in reference
to LAI, TDM, and grain yield in potential
