Evaluation of growth analysis and traits correlation in eight Rapeseed cultivars under optimum and late planting date

In order to evaluate the effect of sowing date on growth analysis, physiological and morphological traits eight rapeseed cultivars, a field experiment was carried out cropping in Bojnourd. The experiment was conducted as split plot design with three replications. Main plot including sowing date (Sep.21, Oct.17) and sub plot were cultivars(Zarfam, Licord, Ebonit, SLM046, Opera, Elvis, Okapi and Orient) Investigated traits included: TDM, RGR, CGR, plant height, crown diameter, sub branches number, pod length, pod per plant, grain per pod, 1000 grain weight and grain yield. Also traits correlation and growth equations were determined based on growing degree day. Result growth analysis showed that sowing date had not significant effect on TDM, RGR and CGR. However, all cultivars were died in the last sowing date, significant Difference occurred among cultivars for growth analysis traits, but sowing date × cultivar had no effect on TDM and CGR. The maximum of growth indices were detected on Oct.17 and Zarfam and Ebonit cultivars had the maximum of growth in this time. Also sowing date had effect on all characters expect 1000 grain weight and grain yield. A positive correlation were observed between grain yield with pod per plant (r= .68**) and sub branches number (r= .43**), respectively. In conclusion, there is no significant difference between the first and second sowing date, so it is seemed that early sowing date is useful for Bojnourd due to protecting from cool injuring. Also between cultivars, Ebonit and Zarfam, in order, have a priority, respectively.