Study of agronomical, physiological and qualitative characteristics of Canola (Brassica napus) under water stress

In order to study of agronomic، physiologic and qualitative characteristics of Canola (Brassica napus L.) under stress irrigation، an experiment was carried out as randomized complete block designs with three replications at the research field of Shahr-e- Qods Branch، Islamic Azad University، in 2010-2011 year. In this experiment، the irrigation treatment in three levels were including optimize irrigation in total growth period based on 80 millimeter evaporation from class A evaporation pan (control)، stress irrigation from flowering until physiologic maturity، and stress irrigation from silique formation until physiologic maturity، respectively. The results indicated that effect of irrigation treatment on plant height، stem diameter، branch per plant، relative water content (RWC)، water saturation deficiency (WSD)، Chl a and carotenoid، silique length، silique per plant، 1000 seed weight، seed yield، seed oil content، oil yield، harvest index and productivity effort were significant. Stress irrigation from flowering and silique formation decreased the RWC by 43. 1 and 29. 5، Chl a by 32. 7 and 26. 5، and carotenoid by 49. 6 and 31. 8، respectively، in compared to control treatment. In this study، normal irrigation (control) showed the highest seed yield. Seed yield was reduced from 2577 kg. ha-1 at control to 1483 and 1907 kg. ha-1 in stress irrigation from flowering and silique formation، respectively. Positive correlations were observed between seed yield and yield components، except seed number per silique and greteast correlation occurred between seed yield and 1000 seed weight and silique per plant، respectively. Overall، these results showed that stress irrigation from flowering until physiologic maturity had the adversely effects on physiologic and morphologic characteristics and seed yield and dependent traits in compared to stress irrigation from silique formation until physiologic maturity