Effect of Sowing Date on Seed Yield, Yield Components and Some Agronomic Traits of Canola Cultivars in Behbahan Region in Iran

Determination of suitable planting date for canola is important for synchronising of vegetative and reproductive stages of plant with favorable climatic conditions to increase quantity and quality of seed yield. This experiment was conducted for two growing seasons (2006–2008) at Behbahan agricultural research station. A split-plot arrangment in randomized complete block design with four replications was used. Sowing date was assigned to main plots 23 October (mean daily air temperature in the first and second year were 28.5 ºC and 25 ºC, respectively), 01 November (mean daily air temperature in the first and second year were 26.5 ºC and 22.5 ºC, respectively), 11 November (mean daily air temperature in the first and second year were 18.5 ºC and 22 ºC, respectively),
21 November (mean daily air temperature in the first and second year were 13 ºC and
23 ºC, respectively), 01 December (mean daily air temperature in the first and second year were 11.5 ºC and 14.5 ºC respectively), 11 December (mean daily air temperature in the first and second year were 10.5 ºC and 14 ºC, respectively). Hyola 401 hybrid and RGS003 were evaluated in sub-plots. Combined analysis of variance showed that sowing date effect was significant on agronomic traits, seed yield and yield components. The highest seed yield (2573 kg ha-1) was produced in 23 October. Canola cultivars significantly differed for agronomic traits, seed yield, yield components and oil content. Hyola 401 hybrid and RGS003 cultivar seed yield were 2780 and 2344 kg ha-1, respectively. Sowing date × cultivar intraction effect was not significant on pod plant-1, seed yield and oil content. Hyola 401 hybrid in 01 December sowing date had the heightest oil content (44.2%). Hyola 401 hybrid seed yield was higher than RGS003 cultivar in all sowing dates. Hyola 401 hybrid had the heightest seed yield (3886 kg ha-1) in 23 October sowing date. Therefore, the recommended sowing dates for Hyola 401 hybrid is from 23 October to 11 November and for RGS003 cultivar from 23 October to 01 November in Behbahan region.