Effects of Irrigation Frequency on Grain Yield, Oil Content and Yield Components of Canola (Brassica napus L.)

In order to determine the effects of irrigation frequency on grain yield, yield components, and seed oil content of oilseed rape (Brassic napus L.), a field experiment was conducted at agricultural research station of Haji Abad, Iran. Four irrigation frequency treatments including irrigating the crop after 50 (T1), 75 (T2), 100 (T3) and 125 (T4) mm cumulative evaporation from the class A evaporation pan, were arranged in a randomized complete block design (RCBD) with three replications. Results showed that among the studied parameters, grain yield and 1000-garin weight (P<0.01), and number of pods per plant (P<0.05) were significantly affected by irrigation frequency. However, the pod length, number of grain per pod, oil concentration in the grain, and crop height were not affectd significantly. The T1 and T2 treatments had significantly higher grain yield, 1000-garin weight and number of pods per plant than the T3 and T4 treatments.There was no significant difference between T1 and T2 treatments for all of the studied parameters. However, T2 resulted in higher WUE than T1. It appears that canola irrigation after 75 mm cumulative evaporation from calss A evaporation pan which is equivalent to the irrigation frequencies of 14, 20 and24 days in November, December and January respectively, 16-20 days in February to early April and 9 days in late April to early May, would be approperiate and may be recommended for Haji Abad region.