to determine the most suitable sowing date for rapeseed cultivars this study was carried out in busheshr agriculture research center, borazjan in 1997-1998 cropping season using a strip plot design with four replications. rapeseed cultivars were: global, regent, tower, pf7045/91, pf5045/88 and maluka which were sown on four different dates with fifteen days interval (oct.20, nov.5, no. 20 and d...