Crop Loss Assessment and Canola (Brassica napus L.) Impact Factor Analysis in late Planting

Factors such as unprepared seed bed and agronomical elements or local common rotation are usually the cause of conola late planting. This experiment was counducted as randomized complete block desing with four replications in two years 2005-2006 and 2006-2007. Seven planting dates, begining from Nov 6th to late Dec 18th with one week interval, were determined in Ahvaz Agricultural Research to assess canola hybrid Hyola308 crop loss and analyze yield impact factors in late planting. Results showed that the delay in canola planting caused a significant effect on the increase of the interval between planting and emergence, reduction seed emergence percent, flowering and maturity duration. Reduction in reproductive length led to a significant loss in pod per plant, seed per pod, and thousands seed weight. Each day delay to a reduction of seed and oil by 2.6 percent. Traits and yield component correlations, direct and indirect effect path analysis showed that flowering initiation had the most direct and indirect effects via other factors on seed and oil yield, so the sowing date must be regulated in such a way that flowering initiation happens with optimum condition (Feb 3th), and with 14-17C environemtal temperature.