Effect of Sowing Date on Seed Yield and Its Components of Canola Cultivars in Varamin Region in Iran

To evaluate the effect of sowing date on seed yield and some agronomic traits of canola cultivars, an experiment was carried out as split plot arrangement in randomized complete block design with four replications in Varamin field station in two growing seasons (2007-2009). Four sowing dates (Sep. 11, Sep. 26, Oct. 11 and Oct. 26) and five canola cultivars (Hayola401, RGS003, Sarigol, Okapi and Zarfam) were assigned to the main and sub plots, respectively. The mean ambient temperatures were 27.4°C and 23.8°C at the first and second sowing dates (10th and 25th of September) and 22.5°C and 17.1°C at third and fourth sowing dates (the 10th and 25th October), respectively. Results showed that the highest seed yield was obtained from cultivar RGS003. The highest seed yield (3031 Kg ha-1) was obtained from second sowing date (Sep. 26) with 23.8°C, and the lowest seed yield (2173 Kg ha-1) from the fourth sowing date (Oct. 26) with 17.1°C. RGS003 and Okapi had the highest (1167 Kg ha-1) and the lowest (997 Kg ha-1) mean of oil yield, respectively. Mean oil content at different sowing dates showed that the highest oil content (42.6%) obtained from second sowing date (Sep. 26) with 23.8°C and the lowest mean of oil content (37.3%) was also achieved from the fourth sowing date with 17.1°C (Oct.26).