Effects of sowing date and plant density on yield components and vegetative traits of Canola in Mazandaran.

In order to study the effects of sowing date and plant density, yield components, some vegetative characteristics and developmental stages, oilseed rape (var. regent), this experiment was conducted in Dasht- e – Naz, Sari of Mazandaran Province. A split plot design with four replications was used. Sowing dates (7 and 22 October and 15 November) and within row spacing (3, 6, 9 and 12 cm) were considered as the main and subplots, respectively. The effects of sowing date on the number of days from planting to germination, four- leaves stage, flowering and maturity were significant and late planting delayed germination and the occurrences of four- leaves stage, but flowering and maturity stages were accelerated. Plant spacing and interaction between sowing date and plant spacing had no significant effect on development stages. Early planting increased vegetative characteristics. At the first sowing date, because of favorable environmental conditions, plant height, number of secondary branches, plant dry weight and biological yield were increased. Stem thickness, number of secondary branches and plant dry weight were increased with increase in plant spacing. Number of pod per plant and square meter and 1000 seed weight were affected by sowing date and early planting increased them, but the number of seed per pod was not affected by sowing date. Among the yield components, number of pod per plant increased with decreasing of density, but number of pod per square meter decreased. Seed yield and oil percentage were affected significantly by sowing date and plant spacing. Early planting increased these traits and the maximum yield obtained for 3 cm within row spacing. The maximum yield per plant and oil percentage was obtained with 12 cm within row spacing. The results showed that 1000 seed weight, number of pod per square meter, number of seed per pod and plant height were the most casual of yield variation and 1000 seed weight explained 76% of its variation. Seed yield showed heigh correlation with 1000 seed weight, number of pod per square meter, plant height and oil yield.