Climatic variation, continuously increasing population and market infrastructure are driven forces to reduce agricultural productivity and new management options and appropriate genotypes are the need of the day to be considered for sustainable production. Crop simulation models can be complementary tools in field experiments to develop innovative crop management systems under continuous varying climatic conditions. In this perspective, two dynamic crop growth models viz., APSIM (Agricultural Production System Simulator) and DSSAT (Decision Support System for Agro Technology Transfer) were calibrated and validated to predict growth and yield of wheat under rainfed conditions for Pothwar region of Pakistan. Experiment was laid out in Randomized Complete Block Design with five wheat varieties namely; Tatara, NARC-2009, Sehar-2006, SKD-1 and F-Sarhad were planted by keeping individual plot size of 5 m x 3 m with row spacing of 25 cm. Both the models were parameterized using different agronomic parameters (phenological development, days after sowing, drymatter accumulation, leaf area index and grain yield) and climatic data.

Temperature in terms of thermal units could influence the crop growth and yield. Similarly different climatic and moisture regime may alter crop phenology, physiology and development and it may be induced on the crop by sowing crop under different sowing dates or environments(years).Keeping in view the findings of current study it may be concluded that crop respond variably under changing climate.Similarly, its need of time to develop a model between environmental variables like temperature and PTQ with crop yield under local environments in order to sustained crop productivity and to mitigate climate extremes events like El-Nino and La-Nina.

Paksitan is facing chronic deficiency of edible oils.70% of the requirement is met through import of edible oil by spending 32 billion rupees annually.This effort is being made to bridge the gap between local production and demand of the country.The evaluation and selection of improved varieties in accordance with local climatic and soil conditions is one of the important agronomic practices for higher yields.The genotype environment interaction is the key factor in the assessment of crop variety performance. Adoption of the cultivars with higher yield potential and wide range of adaptability to edaphic and climatic conditions is essential for increasing yeild per unit area ultimatley boosting up total production.