Oilseed crops have a specific place in Indian agriculture because oil is an important ingredient in the diet of the people. Among oilseed crops of India, Brassica species, altogether known as mustard and rapeseed, rank second in area and production after groundnut (Chopra and Prasad, 1996). In spite of good efforts made in the field of development of higher yielding varieties the average productivity in India (706 kg/ha) is far below leading Brassica producers of the world (France 2185 kg/ha; Germany 3906 kg/ha and 1110 kg/ha).
Many crop growth models have been used to evaluate the climatic yield potentials for various crops. BRASSICA model of Rao (1992) was developed in the line of SOYGROW and PNUTGROW which simulates growth, yield and yield attributes under non limiting moisture and nutrient conditions.
The present paper deals with the testing of BRASSICA model with the data set generated at Anand (Lat 22* 35' N, Long 72* 55' E and Alt 45.1 m) and Sardarkrishinagar (Lat 24* 19' N. Long 72* 19' E and Alt 154.5 m) stations for two cultivars Varuna and GM - 1. The growth and yield were simulated using weather data of these two stations for the period 1992-94. The results revealed that the model simulated the phenology correctly particularly up to flowering period at both the stations, however, it was found that the model overestimated the maturity dates particularly for late sown crops. The simulated seed yield was less than the observed at S.K. Nagar while it was higher at Anand. Under irrigated condition it under estimated. It was found that model does not take into account the effects of pest and diseases which is a major factor in yield reduction in these areas. Moreover it was also found that the simulated yields increased with delaying sowing date which was not in agreement with the observed trend.