Investigation the Response of Rapeseed Cultivars to Moisture Regimes in Different Growth Stages

In order to evaluate the response of rapeseed cultivars to moisture regimes and correlation analysis in different growth stages, a field experiment was conducted in 2006-7 in seed and plant improvement institute of Karaj, Iran. Results showed that number of pods per plant, pod length, stem diameter, 1000-seed weight, oil seed content and branch numbers per plant were reduced significantly under water deficit stress. Also, grain yield was decreased more than biological yield and this resulted in decreased harvest index. Correlation coefficient analysis revealed that number of pods per plant, number of seeds per main and secondary pod, 1000-seed weight, pod length, biological yield and oil seed content had positive and significant correlation with seed yield. Stopping the irrigation from flowering stage also had undesirable effect on seed yield and its components. Among cultivars, Opera cultivar produced more seed yield (4053 kg ha-1) than the others under normal irrigation and under water deficit stress conditions, Zarfam cultivar had the maximum seed yield during stem elongation (3569 kg ha-1), flowering (2135 kg ha-1) and podding stages (2476 kg ha-1). Okapi had the least changes of oil content than other cultivars. Based on the result of this study can be concluded that Zarfam cultivar had better capability to tolerate drought stress and could produce greater seed yield under stress conditions