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In order to study the effect of limited-irrigation stress on canola cultivars, an experiment was conducted in 2007-2008 at the Safiabad agricultural research center. The design was a split plot in a completely randomized block basis with three replications. Main plots were consisted of 4 levels of limited-irrigation, irrigation based on 60 mm cumulative evaporation (Control), withholding irrigation in flowering stage, withholding irrigation in pod initiation and irrigation withholding in grain filling period, and subplots were 5 canola cultivars (Hyola308, Hyola330, Hyola401, Hyola420 and RGS003). The mean comparison of interaction showed that the highest (3155.55 kg.ha-1) grain yield appointed to Hyola420 cultivar in optimum irrigation (control treatment), and the lowest (1491.66 kg.ha-1) belonged to RGS003 cultivar at withholding irrigation in pod initiation period. The maximum (161.42) number of pods observed on Hyola330 cultivar at optimum irrigation (irrigation after 60 mm cumulative evaporation), and the minimum (78.1) ones appointed to RGS003 cultivar at withholding irrigation in pod initiation period. Results showed that there was no significant difference among withholding irrigation, cultivars and the interaction effect of them for oil content. By considering the results of this experiment, withholding irrigation at flowering, pod initiation and grain filling periods leads to decrease grain yield by 24.72%, 14.33% and 11%, respectively. Reduction of grain yield due to the withholding irrigation during flowering, podding and grain filling stages was along with a decrease in the number of pods per plant and thousand seed weight. By considering the results of experiment, withholding irrigation in flowering stage has to be avoided.

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A field experiment was carried out to study the yield, quality and some morphological traits responses of spring canola (Brassica napus L.) to boron application and sowing date, in Ramin Agriculture and Natural Resources University of Khuzestan in 2013-2014. The experiment was carried out as a split plots design in basis of RCBD with three replications. Planting dates (18 November, 3 December, 17 December and 30 December) and boron application treatments (control, 10 kg B.ha^-1 incorporated with soil, boron spraying at 6 leaf stage and budding stages) were investigated as main and sub plots, respectively. Planting dates and boron application had significant effects on morphological traits, yield and quality of canola. The interaction effect of sowing date and boron on grain number per siliquie was significant. Late planting caused to significant decreased yield and its components. However, boron application incorporated with soil caused to compensate the negative effect of late planting. Generally, the highest grain yield (4579.7 kg.ha^-1) was obtained from sowing at 18 November and 10 kg boron.ha^-1 incorporated with soil, and lowest grain yield was obtained from planting at 30 December and without boron application. Delayed planting result in lowering morphological traits including plant height and branching. Delayed planting also caused by decreased grain oil and leaf N percentage, and increased grain N percentage. Boron application caused by significant plant boron content, but had no significant on grain oil ad N, and leaf N content. Also, boron application, in the experiment had no significant effect on alleviation of yield loss due to delayed canola sowing.