Effects of Cut off the Irrigation in Different Growth Stages on Yield and Yield Components of Rapeseed Cultivars

Iran is a country of water scarcity due to general low precipitation, high evaporation and the temporal and spatial distribution of rainfall. In order to determine the effects of disruption of irrigation in different growth stages of autumn’s rapeseed cultivars, an experiment was conducted in 2009-2010 at Isfahan agriculture research station. A split plot layout within a randomized complete block design 3 replications was used. Main plots were seven levels of cut off irrigation namely, D1= current irrigation or irrigation after 80 millimeter vaporize from class A basin to physiological maturity, D2= cut off irrigation from stem elongation phase and then on, D3= cut off the irrigation from flowering and then on, D4= cut off the irrigation from pod formation phase and then on, D5= cut off the irrigation in stem and flowering phase, D6= cut off the irrigation in stem and pod phase, D7= cut off the irrigation in flower and pod formation, and sub plots were two rapeseed cultivars, namely, Zarfam and Okapi. With increasing the number of irrigation, rapeseed yield will increase, but if the water lacks occurred, it is better not to cut off irrigation in flower and stem phase, in order to get acceptable seed and oil yield. Zarfam had the highest oil and seed yield in withheld irrigation conditions and also have the best adaptation in water deficit conditions.