Response of Canola Cultivars and Hybrids to WinterCultivation under Late Season Drought Stress

Background & Objective: Selection of suitable canola cultivars for winter cultivation and tolerant to late-season drought stress, are the basic strategies for the cultivation of the rapeseed in cold temperate regions with semi-arid climate. Materials & Methods: A factorial split-plot based on complete randomized blocks design was conducted with three replications for two years (2014-2016) in Karaj. In this regards, sowing dates were divided into two levels of fall cultivation (Oct. 7) and winter cultivation (Feb. 4); irrigation was carried out in three levels of normal irrigation (control), irrigation interruption from flowering, and after pod formation stages and five canola cultivars include Sarigol, Dalgan, Jacomo, Jeromeh and Hyola401.    Results: The interaction effect of sowing date × irrigation × cultivar was significant on the traits of number of pods per square meter, number of seeds per pod, biological yield, seed yield, relative water content (RWC) of leaves and proline at the level of 1%, and on the traits of 1000-seeds weight, canopy temperature and chlorophyll b content at the level of 5%. Here we show that Dalgan cultivar was obtained with a seed yield of 3657 kg ha-1 and RWC of 92.42%, in the winter cultivation date and normal irrigation condition. Moreover, in winter cultivation and in the late season drought stress condition (irrigation interruption after flowering stage onwards), the Hyola 401 hybrid was obtained with seed yield of 2376 kg ha-1‎ and a RWC of 83.11%.   Conclusion: In The winter cultivation and normal irrigation condition Dalgan cultivar and in the late season drought stress condition (irrigation interruption after pod formation stage), the Hyola 401 and Jeromeh hybridscan be used in the development of canola cultivation in the new status of winter cultivation (Feb. 4) and various irrigation conditions.