The role of sowing date, seeding rate and row spacing on yield component variations and increase of seed and oil yield of canola in east of Golestan

In order to evaluate the effect of agronomic management (sowing date, seeding rate and row spacing) on yield components, oil percent and seed and oil yield of canola (RGS003 cultivar), an experiment was conducted at the Agricultural Research Station of Gonbad during 2003–2005. The experiment was a split plot factorial arranged in an RCBD with four replications. Three sowing dates (Nov. 6th, Nov. 21st and Dec. 6th) were as main plots and three seeding rates (4, 7 and 10 kg/ha) and two row spacing (12 and 24 cm) were subplots in a factorial arrangement. The first sowing date had the highest seed yield, because of suitabletemperature conditions at the beginning of growing season, earlier seedling establishment and higher number of pods per plant. The mean seed yield of first, second and third sowing dates were3512, 2827 and 2742 kg/ha, respectively. The significant difference of year×seeding rate interaction was due to different trend of seed yield variation with seeding rate increase in the two years of the experiment. In the first year of the experiment the seed yield decreased with an increase in increase in seeding rate because of higherlodging, whereas this trend was not observed in the second year of the experiment. The seed yield decreased with an increase inrow spacing. The mean seed yield atrow spacing of 12 and 24 cm was 3158 and 2896 kg/ha, respectively. Finally with regard to two year results of the experiment, the second decade of Aban (Nov. 1st-10th) sowing date, 6-8 kg/ha seeding rate and 12-18 cm row spacing are recommended for canola planting in Gonbad and Kalaleh area and also, RGS003 as a cultivar with good seed yield and agronomiccharacteristics can be planted in the area.