Investigation the effects of water stress on yield and yield components of canola winter varieties.

In order to investigate the effect of water stress on yield and yield components of canola winter varieties, a split plot design was conducted as base of randomized complete block design with four replications at the research farm of Seed and Plant Improvement Institute, Karaj, Iran, in 2006. Irrigation regimes were assigned to main plots at two levels (I1= irrigation after 80 mm evaporation from class an evaporation pan or normal irrigation and I2= irrigation interrupting at pod development stage and after that) and twelve canola cultivars (SW.056, Ebonite, Alice, RG-9908, Adder, ARC-2, ARG-91004, Opera, Geronimo, Elvice, Okapi and Zarfam) as sub plots were considered. The results demonstrated that interrupting of irrigation at pod development stage and after that significantly decreased pod number per plant, number of seed per pod, 1000-grain weight, number of branches per plant and gain yield. The water stress conditions, highest grain yield (4200 kg/ha) was obtained from Geronimo cultivar but the not water stress conditions (normal irrigation), RG-9908 cultivar produced highest grain yield (5000 kg/ha). Also after Geronimo cultivar were, Zarfam (3625 kg/ha), ARG-91004 (3525 kg/ha), Ebonite and Elvice (3500 kg/ha) cultivars respectively best cultivars for water deficit stress conditions and produced maximum grain yield. Traits simple correlation showed that grain yield with pod number per plant and number of seed per pod was positive and significant correlation.